3322 lines
91 KiB
C
3322 lines
91 KiB
C
/*-------------------------------------------------------------------------
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*
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* deparse.c
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* Query deparser for postgres_fdw
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*
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* This file includes functions that examine query WHERE clauses to see
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* whether they're safe to send to the remote server for execution, as
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* well as functions to construct the query text to be sent. The latter
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* functionality is annoyingly duplicative of ruleutils.c, but there are
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* enough special considerations that it seems best to keep this separate.
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* One saving grace is that we only need deparse logic for node types that
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* we consider safe to send.
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*
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* We assume that the remote session's search_path is exactly "pg_catalog",
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* and thus we need schema-qualify all and only names outside pg_catalog.
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*
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* We do not consider that it is ever safe to send COLLATE expressions to
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* the remote server: it might not have the same collation names we do.
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* (Later we might consider it safe to send COLLATE "C", but even that would
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* fail on old remote servers.) An expression is considered safe to send
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* only if all operator/function input collations used in it are traceable to
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* Var(s) of the foreign table. That implies that if the remote server gets
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* a different answer than we do, the foreign table's columns are not marked
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* with collations that match the remote table's columns, which we can
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* consider to be user error.
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*
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* Portions Copyright (c) 2012-2019, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/postgres_fdw/deparse.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "postgres_fdw.h"
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#include "access/heapam.h"
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#include "access/htup_details.h"
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#include "access/sysattr.h"
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#include "catalog/pg_aggregate.h"
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#include "catalog/pg_collation.h"
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#include "catalog/pg_namespace.h"
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#include "catalog/pg_operator.h"
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#include "catalog/pg_proc.h"
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#include "catalog/pg_type.h"
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#include "commands/defrem.h"
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#include "nodes/makefuncs.h"
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#include "nodes/nodeFuncs.h"
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#include "nodes/plannodes.h"
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#include "optimizer/clauses.h"
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#include "optimizer/prep.h"
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#include "optimizer/tlist.h"
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#include "optimizer/var.h"
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#include "parser/parsetree.h"
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#include "utils/builtins.h"
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#include "utils/lsyscache.h"
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#include "utils/rel.h"
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#include "utils/syscache.h"
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#include "utils/typcache.h"
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/*
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* Global context for foreign_expr_walker's search of an expression tree.
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*/
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typedef struct foreign_glob_cxt
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{
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PlannerInfo *root; /* global planner state */
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RelOptInfo *foreignrel; /* the foreign relation we are planning for */
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Relids relids; /* relids of base relations in the underlying
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* scan */
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} foreign_glob_cxt;
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/*
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* Local (per-tree-level) context for foreign_expr_walker's search.
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* This is concerned with identifying collations used in the expression.
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*/
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typedef enum
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{
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FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
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* it has default collation that is not
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* traceable to a foreign Var */
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FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
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FDW_COLLATE_UNSAFE /* collation is non-default and derives from
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* something other than a foreign Var */
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} FDWCollateState;
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typedef struct foreign_loc_cxt
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{
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Oid collation; /* OID of current collation, if any */
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FDWCollateState state; /* state of current collation choice */
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} foreign_loc_cxt;
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/*
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* Context for deparseExpr
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*/
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typedef struct deparse_expr_cxt
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{
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PlannerInfo *root; /* global planner state */
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RelOptInfo *foreignrel; /* the foreign relation we are planning for */
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RelOptInfo *scanrel; /* the underlying scan relation. Same as
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* foreignrel, when that represents a join or
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* a base relation. */
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StringInfo buf; /* output buffer to append to */
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List **params_list; /* exprs that will become remote Params */
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} deparse_expr_cxt;
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#define REL_ALIAS_PREFIX "r"
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/* Handy macro to add relation name qualification */
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#define ADD_REL_QUALIFIER(buf, varno) \
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appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
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#define SUBQUERY_REL_ALIAS_PREFIX "s"
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#define SUBQUERY_COL_ALIAS_PREFIX "c"
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/*
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* Functions to determine whether an expression can be evaluated safely on
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* remote server.
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*/
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static bool foreign_expr_walker(Node *node,
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foreign_glob_cxt *glob_cxt,
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foreign_loc_cxt *outer_cxt);
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static char *deparse_type_name(Oid type_oid, int32 typemod);
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/*
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* Functions to construct string representation of a node tree.
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*/
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static void deparseTargetList(StringInfo buf,
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RangeTblEntry *rte,
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Index rtindex,
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Relation rel,
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bool is_returning,
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Bitmapset *attrs_used,
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bool qualify_col,
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List **retrieved_attrs);
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static void deparseExplicitTargetList(List *tlist,
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bool is_returning,
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List **retrieved_attrs,
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deparse_expr_cxt *context);
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static void deparseSubqueryTargetList(deparse_expr_cxt *context);
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static void deparseReturningList(StringInfo buf, RangeTblEntry *rte,
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Index rtindex, Relation rel,
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bool trig_after_row,
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List *withCheckOptionList,
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List *returningList,
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List **retrieved_attrs);
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static void deparseColumnRef(StringInfo buf, int varno, int varattno,
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RangeTblEntry *rte, bool qualify_col);
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static void deparseRelation(StringInfo buf, Relation rel);
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static void deparseExpr(Expr *expr, deparse_expr_cxt *context);
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static void deparseVar(Var *node, deparse_expr_cxt *context);
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static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype);
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static void deparseParam(Param *node, deparse_expr_cxt *context);
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static void deparseArrayRef(ArrayRef *node, deparse_expr_cxt *context);
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static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
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static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
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static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
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static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
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static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
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deparse_expr_cxt *context);
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static void deparseRelabelType(RelabelType *node, deparse_expr_cxt *context);
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static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context);
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static void deparseNullTest(NullTest *node, deparse_expr_cxt *context);
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static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context);
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static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
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deparse_expr_cxt *context);
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static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
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deparse_expr_cxt *context);
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static void deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
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deparse_expr_cxt *context);
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static void deparseLockingClause(deparse_expr_cxt *context);
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static void appendOrderByClause(List *pathkeys, deparse_expr_cxt *context);
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static void appendConditions(List *exprs, deparse_expr_cxt *context);
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static void deparseFromExprForRel(StringInfo buf, PlannerInfo *root,
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RelOptInfo *foreignrel, bool use_alias,
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Index ignore_rel, List **ignore_conds,
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List **params_list);
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static void deparseFromExpr(List *quals, deparse_expr_cxt *context);
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static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root,
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RelOptInfo *foreignrel, bool make_subquery,
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Index ignore_rel, List **ignore_conds, List **params_list);
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static void deparseAggref(Aggref *node, deparse_expr_cxt *context);
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static void appendGroupByClause(List *tlist, deparse_expr_cxt *context);
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static void appendAggOrderBy(List *orderList, List *targetList,
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deparse_expr_cxt *context);
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static void appendFunctionName(Oid funcid, deparse_expr_cxt *context);
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static Node *deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
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deparse_expr_cxt *context);
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/*
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* Helper functions
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*/
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static bool is_subquery_var(Var *node, RelOptInfo *foreignrel,
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int *relno, int *colno);
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static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
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int *relno, int *colno);
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/*
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* Examine each qual clause in input_conds, and classify them into two groups,
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* which are returned as two lists:
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* - remote_conds contains expressions that can be evaluated remotely
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* - local_conds contains expressions that can't be evaluated remotely
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*/
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void
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classifyConditions(PlannerInfo *root,
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RelOptInfo *baserel,
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List *input_conds,
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List **remote_conds,
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List **local_conds)
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{
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ListCell *lc;
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*remote_conds = NIL;
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*local_conds = NIL;
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foreach(lc, input_conds)
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{
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RestrictInfo *ri = lfirst_node(RestrictInfo, lc);
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if (is_foreign_expr(root, baserel, ri->clause))
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*remote_conds = lappend(*remote_conds, ri);
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else
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*local_conds = lappend(*local_conds, ri);
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}
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}
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/*
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* Returns true if given expr is safe to evaluate on the foreign server.
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*/
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bool
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is_foreign_expr(PlannerInfo *root,
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RelOptInfo *baserel,
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Expr *expr)
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{
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foreign_glob_cxt glob_cxt;
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foreign_loc_cxt loc_cxt;
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PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
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/*
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* Check that the expression consists of nodes that are safe to execute
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* remotely.
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*/
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glob_cxt.root = root;
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glob_cxt.foreignrel = baserel;
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/*
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* For an upper relation, use relids from its underneath scan relation,
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* because the upperrel's own relids currently aren't set to anything
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* meaningful by the core code. For other relation, use their own relids.
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*/
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if (IS_UPPER_REL(baserel))
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glob_cxt.relids = fpinfo->outerrel->relids;
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else
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glob_cxt.relids = baserel->relids;
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loc_cxt.collation = InvalidOid;
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loc_cxt.state = FDW_COLLATE_NONE;
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if (!foreign_expr_walker((Node *) expr, &glob_cxt, &loc_cxt))
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return false;
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/*
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* If the expression has a valid collation that does not arise from a
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* foreign var, the expression can not be sent over.
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*/
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if (loc_cxt.state == FDW_COLLATE_UNSAFE)
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return false;
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/*
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* An expression which includes any mutable functions can't be sent over
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* because its result is not stable. For example, sending now() remote
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* side could cause confusion from clock offsets. Future versions might
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* be able to make this choice with more granularity. (We check this last
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* because it requires a lot of expensive catalog lookups.)
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*/
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if (contain_mutable_functions((Node *) expr))
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return false;
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/* OK to evaluate on the remote server */
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return true;
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}
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/*
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* Check if expression is safe to execute remotely, and return true if so.
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*
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* In addition, *outer_cxt is updated with collation information.
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*
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* We must check that the expression contains only node types we can deparse,
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* that all types/functions/operators are safe to send (they are "shippable"),
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* and that all collations used in the expression derive from Vars of the
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* foreign table. Because of the latter, the logic is pretty close to
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* assign_collations_walker() in parse_collate.c, though we can assume here
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* that the given expression is valid. Note function mutability is not
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* currently considered here.
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*/
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static bool
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foreign_expr_walker(Node *node,
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foreign_glob_cxt *glob_cxt,
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foreign_loc_cxt *outer_cxt)
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{
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bool check_type = true;
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PgFdwRelationInfo *fpinfo;
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foreign_loc_cxt inner_cxt;
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Oid collation;
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FDWCollateState state;
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/* Need do nothing for empty subexpressions */
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if (node == NULL)
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return true;
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/* May need server info from baserel's fdw_private struct */
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fpinfo = (PgFdwRelationInfo *) (glob_cxt->foreignrel->fdw_private);
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/* Set up inner_cxt for possible recursion to child nodes */
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inner_cxt.collation = InvalidOid;
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inner_cxt.state = FDW_COLLATE_NONE;
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switch (nodeTag(node))
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{
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case T_Var:
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{
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Var *var = (Var *) node;
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/*
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* If the Var is from the foreign table, we consider its
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* collation (if any) safe to use. If it is from another
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* table, we treat its collation the same way as we would a
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* Param's collation, ie it's not safe for it to have a
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* non-default collation.
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*/
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if (bms_is_member(var->varno, glob_cxt->relids) &&
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var->varlevelsup == 0)
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{
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/* Var belongs to foreign table */
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/*
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* System columns other than ctid should not be sent to
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* the remote, since we don't make any effort to ensure
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* that local and remote values match (tableoid, in
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* particular, almost certainly doesn't match).
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*/
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if (var->varattno < 0 &&
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var->varattno != SelfItemPointerAttributeNumber)
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return false;
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/* Else check the collation */
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collation = var->varcollid;
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state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
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}
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else
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{
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/* Var belongs to some other table */
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collation = var->varcollid;
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if (collation == InvalidOid ||
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collation == DEFAULT_COLLATION_OID)
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{
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/*
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* It's noncollatable, or it's safe to combine with a
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* collatable foreign Var, so set state to NONE.
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*/
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state = FDW_COLLATE_NONE;
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}
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else
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{
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/*
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* Do not fail right away, since the Var might appear
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* in a collation-insensitive context.
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*/
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state = FDW_COLLATE_UNSAFE;
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}
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}
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}
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break;
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case T_Const:
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{
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Const *c = (Const *) node;
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|
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/*
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* If the constant has nondefault collation, either it's of a
|
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* non-builtin type, or it reflects folding of a CollateExpr.
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* It's unsafe to send to the remote unless it's used in a
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* non-collation-sensitive context.
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*/
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collation = c->constcollid;
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if (collation == InvalidOid ||
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collation == DEFAULT_COLLATION_OID)
|
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state = FDW_COLLATE_NONE;
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else
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state = FDW_COLLATE_UNSAFE;
|
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}
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break;
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case T_Param:
|
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{
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Param *p = (Param *) node;
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|
|
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/*
|
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* Collation rule is same as for Consts and non-foreign Vars.
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*/
|
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collation = p->paramcollid;
|
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if (collation == InvalidOid ||
|
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collation == DEFAULT_COLLATION_OID)
|
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state = FDW_COLLATE_NONE;
|
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else
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state = FDW_COLLATE_UNSAFE;
|
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}
|
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break;
|
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case T_ArrayRef:
|
|
{
|
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ArrayRef *ar = (ArrayRef *) node;
|
|
|
|
/* Assignment should not be in restrictions. */
|
|
if (ar->refassgnexpr != NULL)
|
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return false;
|
|
|
|
/*
|
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* Recurse to remaining subexpressions. Since the array
|
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* subscripts must yield (noncollatable) integers, they won't
|
|
* affect the inner_cxt state.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) ar->refupperindexpr,
|
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glob_cxt, &inner_cxt))
|
|
return false;
|
|
if (!foreign_expr_walker((Node *) ar->reflowerindexpr,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
if (!foreign_expr_walker((Node *) ar->refexpr,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* Array subscripting should yield same collation as input,
|
|
* but for safety use same logic as for function nodes.
|
|
*/
|
|
collation = ar->refcollid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
case T_FuncExpr:
|
|
{
|
|
FuncExpr *fe = (FuncExpr *) node;
|
|
|
|
/*
|
|
* If function used by the expression is not shippable, it
|
|
* can't be sent to remote because it might have incompatible
|
|
* semantics on remote side.
|
|
*/
|
|
if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
|
|
return false;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) fe->args,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* If function's input collation is not derived from a foreign
|
|
* Var, it can't be sent to remote.
|
|
*/
|
|
if (fe->inputcollid == InvalidOid)
|
|
/* OK, inputs are all noncollatable */ ;
|
|
else if (inner_cxt.state != FDW_COLLATE_SAFE ||
|
|
fe->inputcollid != inner_cxt.collation)
|
|
return false;
|
|
|
|
/*
|
|
* Detect whether node is introducing a collation not derived
|
|
* from a foreign Var. (If so, we just mark it unsafe for now
|
|
* rather than immediately returning false, since the parent
|
|
* node might not care.)
|
|
*/
|
|
collation = fe->funccollid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
case T_OpExpr:
|
|
case T_DistinctExpr: /* struct-equivalent to OpExpr */
|
|
{
|
|
OpExpr *oe = (OpExpr *) node;
|
|
|
|
/*
|
|
* Similarly, only shippable operators can be sent to remote.
|
|
* (If the operator is shippable, we assume its underlying
|
|
* function is too.)
|
|
*/
|
|
if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
|
|
return false;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) oe->args,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* If operator's input collation is not derived from a foreign
|
|
* Var, it can't be sent to remote.
|
|
*/
|
|
if (oe->inputcollid == InvalidOid)
|
|
/* OK, inputs are all noncollatable */ ;
|
|
else if (inner_cxt.state != FDW_COLLATE_SAFE ||
|
|
oe->inputcollid != inner_cxt.collation)
|
|
return false;
|
|
|
|
/* Result-collation handling is same as for functions */
|
|
collation = oe->opcollid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
case T_ScalarArrayOpExpr:
|
|
{
|
|
ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
|
|
|
|
/*
|
|
* Again, only shippable operators can be sent to remote.
|
|
*/
|
|
if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
|
|
return false;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) oe->args,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* If operator's input collation is not derived from a foreign
|
|
* Var, it can't be sent to remote.
|
|
*/
|
|
if (oe->inputcollid == InvalidOid)
|
|
/* OK, inputs are all noncollatable */ ;
|
|
else if (inner_cxt.state != FDW_COLLATE_SAFE ||
|
|
oe->inputcollid != inner_cxt.collation)
|
|
return false;
|
|
|
|
/* Output is always boolean and so noncollatable. */
|
|
collation = InvalidOid;
|
|
state = FDW_COLLATE_NONE;
|
|
}
|
|
break;
|
|
case T_RelabelType:
|
|
{
|
|
RelabelType *r = (RelabelType *) node;
|
|
|
|
/*
|
|
* Recurse to input subexpression.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) r->arg,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* RelabelType must not introduce a collation not derived from
|
|
* an input foreign Var (same logic as for a real function).
|
|
*/
|
|
collation = r->resultcollid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
case T_BoolExpr:
|
|
{
|
|
BoolExpr *b = (BoolExpr *) node;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) b->args,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/* Output is always boolean and so noncollatable. */
|
|
collation = InvalidOid;
|
|
state = FDW_COLLATE_NONE;
|
|
}
|
|
break;
|
|
case T_NullTest:
|
|
{
|
|
NullTest *nt = (NullTest *) node;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) nt->arg,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/* Output is always boolean and so noncollatable. */
|
|
collation = InvalidOid;
|
|
state = FDW_COLLATE_NONE;
|
|
}
|
|
break;
|
|
case T_ArrayExpr:
|
|
{
|
|
ArrayExpr *a = (ArrayExpr *) node;
|
|
|
|
/*
|
|
* Recurse to input subexpressions.
|
|
*/
|
|
if (!foreign_expr_walker((Node *) a->elements,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* ArrayExpr must not introduce a collation not derived from
|
|
* an input foreign Var (same logic as for a function).
|
|
*/
|
|
collation = a->array_collid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
case T_List:
|
|
{
|
|
List *l = (List *) node;
|
|
ListCell *lc;
|
|
|
|
/*
|
|
* Recurse to component subexpressions.
|
|
*/
|
|
foreach(lc, l)
|
|
{
|
|
if (!foreign_expr_walker((Node *) lfirst(lc),
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* When processing a list, collation state just bubbles up
|
|
* from the list elements.
|
|
*/
|
|
collation = inner_cxt.collation;
|
|
state = inner_cxt.state;
|
|
|
|
/* Don't apply exprType() to the list. */
|
|
check_type = false;
|
|
}
|
|
break;
|
|
case T_Aggref:
|
|
{
|
|
Aggref *agg = (Aggref *) node;
|
|
ListCell *lc;
|
|
|
|
/* Not safe to pushdown when not in grouping context */
|
|
if (!IS_UPPER_REL(glob_cxt->foreignrel))
|
|
return false;
|
|
|
|
/* Only non-split aggregates are pushable. */
|
|
if (agg->aggsplit != AGGSPLIT_SIMPLE)
|
|
return false;
|
|
|
|
/* As usual, it must be shippable. */
|
|
if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
|
|
return false;
|
|
|
|
/*
|
|
* Recurse to input args. aggdirectargs, aggorder and
|
|
* aggdistinct are all present in args, so no need to check
|
|
* their shippability explicitly.
|
|
*/
|
|
foreach(lc, agg->args)
|
|
{
|
|
Node *n = (Node *) lfirst(lc);
|
|
|
|
/* If TargetEntry, extract the expression from it */
|
|
if (IsA(n, TargetEntry))
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) n;
|
|
|
|
n = (Node *) tle->expr;
|
|
}
|
|
|
|
if (!foreign_expr_walker(n, glob_cxt, &inner_cxt))
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* For aggorder elements, check whether the sort operator, if
|
|
* specified, is shippable or not.
|
|
*/
|
|
if (agg->aggorder)
|
|
{
|
|
ListCell *lc;
|
|
|
|
foreach(lc, agg->aggorder)
|
|
{
|
|
SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
|
|
Oid sortcoltype;
|
|
TypeCacheEntry *typentry;
|
|
TargetEntry *tle;
|
|
|
|
tle = get_sortgroupref_tle(srt->tleSortGroupRef,
|
|
agg->args);
|
|
sortcoltype = exprType((Node *) tle->expr);
|
|
typentry = lookup_type_cache(sortcoltype,
|
|
TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
|
|
/* Check shippability of non-default sort operator. */
|
|
if (srt->sortop != typentry->lt_opr &&
|
|
srt->sortop != typentry->gt_opr &&
|
|
!is_shippable(srt->sortop, OperatorRelationId,
|
|
fpinfo))
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/* Check aggregate filter */
|
|
if (!foreign_expr_walker((Node *) agg->aggfilter,
|
|
glob_cxt, &inner_cxt))
|
|
return false;
|
|
|
|
/*
|
|
* If aggregate's input collation is not derived from a
|
|
* foreign Var, it can't be sent to remote.
|
|
*/
|
|
if (agg->inputcollid == InvalidOid)
|
|
/* OK, inputs are all noncollatable */ ;
|
|
else if (inner_cxt.state != FDW_COLLATE_SAFE ||
|
|
agg->inputcollid != inner_cxt.collation)
|
|
return false;
|
|
|
|
/*
|
|
* Detect whether node is introducing a collation not derived
|
|
* from a foreign Var. (If so, we just mark it unsafe for now
|
|
* rather than immediately returning false, since the parent
|
|
* node might not care.)
|
|
*/
|
|
collation = agg->aggcollid;
|
|
if (collation == InvalidOid)
|
|
state = FDW_COLLATE_NONE;
|
|
else if (inner_cxt.state == FDW_COLLATE_SAFE &&
|
|
collation == inner_cxt.collation)
|
|
state = FDW_COLLATE_SAFE;
|
|
else if (collation == DEFAULT_COLLATION_OID)
|
|
state = FDW_COLLATE_NONE;
|
|
else
|
|
state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
break;
|
|
default:
|
|
|
|
/*
|
|
* If it's anything else, assume it's unsafe. This list can be
|
|
* expanded later, but don't forget to add deparse support below.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* If result type of given expression is not shippable, it can't be sent
|
|
* to remote because it might have incompatible semantics on remote side.
|
|
*/
|
|
if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
|
|
return false;
|
|
|
|
/*
|
|
* Now, merge my collation information into my parent's state.
|
|
*/
|
|
if (state > outer_cxt->state)
|
|
{
|
|
/* Override previous parent state */
|
|
outer_cxt->collation = collation;
|
|
outer_cxt->state = state;
|
|
}
|
|
else if (state == outer_cxt->state)
|
|
{
|
|
/* Merge, or detect error if there's a collation conflict */
|
|
switch (state)
|
|
{
|
|
case FDW_COLLATE_NONE:
|
|
/* Nothing + nothing is still nothing */
|
|
break;
|
|
case FDW_COLLATE_SAFE:
|
|
if (collation != outer_cxt->collation)
|
|
{
|
|
/*
|
|
* Non-default collation always beats default.
|
|
*/
|
|
if (outer_cxt->collation == DEFAULT_COLLATION_OID)
|
|
{
|
|
/* Override previous parent state */
|
|
outer_cxt->collation = collation;
|
|
}
|
|
else if (collation != DEFAULT_COLLATION_OID)
|
|
{
|
|
/*
|
|
* Conflict; show state as indeterminate. We don't
|
|
* want to "return false" right away, since parent
|
|
* node might not care about collation.
|
|
*/
|
|
outer_cxt->state = FDW_COLLATE_UNSAFE;
|
|
}
|
|
}
|
|
break;
|
|
case FDW_COLLATE_UNSAFE:
|
|
/* We're still conflicted ... */
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* It looks OK */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Convert type OID + typmod info into a type name we can ship to the remote
|
|
* server. Someplace else had better have verified that this type name is
|
|
* expected to be known on the remote end.
|
|
*
|
|
* This is almost just format_type_with_typemod(), except that if left to its
|
|
* own devices, that function will make schema-qualification decisions based
|
|
* on the local search_path, which is wrong. We must schema-qualify all
|
|
* type names that are not in pg_catalog. We assume here that built-in types
|
|
* are all in pg_catalog and need not be qualified; otherwise, qualify.
|
|
*/
|
|
static char *
|
|
deparse_type_name(Oid type_oid, int32 typemod)
|
|
{
|
|
bits16 flags = FORMAT_TYPE_TYPEMOD_GIVEN;
|
|
|
|
if (!is_builtin(type_oid))
|
|
flags |= FORMAT_TYPE_FORCE_QUALIFY;
|
|
|
|
return format_type_extended(type_oid, typemod, flags);
|
|
}
|
|
|
|
/*
|
|
* Build the targetlist for given relation to be deparsed as SELECT clause.
|
|
*
|
|
* The output targetlist contains the columns that need to be fetched from the
|
|
* foreign server for the given relation. If foreignrel is an upper relation,
|
|
* then the output targetlist can also contain expressions to be evaluated on
|
|
* foreign server.
|
|
*/
|
|
List *
|
|
build_tlist_to_deparse(RelOptInfo *foreignrel)
|
|
{
|
|
List *tlist = NIL;
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
ListCell *lc;
|
|
|
|
/*
|
|
* For an upper relation, we have already built the target list while
|
|
* checking shippability, so just return that.
|
|
*/
|
|
if (IS_UPPER_REL(foreignrel))
|
|
return fpinfo->grouped_tlist;
|
|
|
|
/*
|
|
* We require columns specified in foreignrel->reltarget->exprs and those
|
|
* required for evaluating the local conditions.
|
|
*/
|
|
tlist = add_to_flat_tlist(tlist,
|
|
pull_var_clause((Node *) foreignrel->reltarget->exprs,
|
|
PVC_RECURSE_PLACEHOLDERS));
|
|
foreach(lc, fpinfo->local_conds)
|
|
{
|
|
RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
|
|
|
|
tlist = add_to_flat_tlist(tlist,
|
|
pull_var_clause((Node *) rinfo->clause,
|
|
PVC_RECURSE_PLACEHOLDERS));
|
|
}
|
|
|
|
return tlist;
|
|
}
|
|
|
|
/*
|
|
* Deparse SELECT statement for given relation into buf.
|
|
*
|
|
* tlist contains the list of desired columns to be fetched from foreign server.
|
|
* For a base relation fpinfo->attrs_used is used to construct SELECT clause,
|
|
* hence the tlist is ignored for a base relation.
|
|
*
|
|
* remote_conds is the list of conditions to be deparsed into the WHERE clause
|
|
* (or, in the case of upper relations, into the HAVING clause).
|
|
*
|
|
* If params_list is not NULL, it receives a list of Params and other-relation
|
|
* Vars used in the clauses; these values must be transmitted to the remote
|
|
* server as parameter values.
|
|
*
|
|
* If params_list is NULL, we're generating the query for EXPLAIN purposes,
|
|
* so Params and other-relation Vars should be replaced by dummy values.
|
|
*
|
|
* pathkeys is the list of pathkeys to order the result by.
|
|
*
|
|
* is_subquery is the flag to indicate whether to deparse the specified
|
|
* relation as a subquery.
|
|
*
|
|
* List of columns selected is returned in retrieved_attrs.
|
|
*/
|
|
void
|
|
deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
|
|
List *tlist, List *remote_conds, List *pathkeys,
|
|
bool is_subquery, List **retrieved_attrs,
|
|
List **params_list)
|
|
{
|
|
deparse_expr_cxt context;
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
|
|
List *quals;
|
|
|
|
/*
|
|
* We handle relations for foreign tables, joins between those and upper
|
|
* relations.
|
|
*/
|
|
Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel) || IS_UPPER_REL(rel));
|
|
|
|
/* Fill portions of context common to upper, join and base relation */
|
|
context.buf = buf;
|
|
context.root = root;
|
|
context.foreignrel = rel;
|
|
context.scanrel = IS_UPPER_REL(rel) ? fpinfo->outerrel : rel;
|
|
context.params_list = params_list;
|
|
|
|
/* Construct SELECT clause */
|
|
deparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
|
|
|
|
/*
|
|
* For upper relations, the WHERE clause is built from the remote
|
|
* conditions of the underlying scan relation; otherwise, we can use the
|
|
* supplied list of remote conditions directly.
|
|
*/
|
|
if (IS_UPPER_REL(rel))
|
|
{
|
|
PgFdwRelationInfo *ofpinfo;
|
|
|
|
ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
|
|
quals = ofpinfo->remote_conds;
|
|
}
|
|
else
|
|
quals = remote_conds;
|
|
|
|
/* Construct FROM and WHERE clauses */
|
|
deparseFromExpr(quals, &context);
|
|
|
|
if (IS_UPPER_REL(rel))
|
|
{
|
|
/* Append GROUP BY clause */
|
|
appendGroupByClause(tlist, &context);
|
|
|
|
/* Append HAVING clause */
|
|
if (remote_conds)
|
|
{
|
|
appendStringInfoString(buf, " HAVING ");
|
|
appendConditions(remote_conds, &context);
|
|
}
|
|
}
|
|
|
|
/* Add ORDER BY clause if we found any useful pathkeys */
|
|
if (pathkeys)
|
|
appendOrderByClause(pathkeys, &context);
|
|
|
|
/* Add any necessary FOR UPDATE/SHARE. */
|
|
deparseLockingClause(&context);
|
|
}
|
|
|
|
/*
|
|
* Construct a simple SELECT statement that retrieves desired columns
|
|
* of the specified foreign table, and append it to "buf". The output
|
|
* contains just "SELECT ... ".
|
|
*
|
|
* We also create an integer List of the columns being retrieved, which is
|
|
* returned to *retrieved_attrs, unless we deparse the specified relation
|
|
* as a subquery.
|
|
*
|
|
* tlist is the list of desired columns. is_subquery is the flag to
|
|
* indicate whether to deparse the specified relation as a subquery.
|
|
* Read prologue of deparseSelectStmtForRel() for details.
|
|
*/
|
|
static void
|
|
deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
|
|
deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
RelOptInfo *foreignrel = context->foreignrel;
|
|
PlannerInfo *root = context->root;
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
|
|
/*
|
|
* Construct SELECT list
|
|
*/
|
|
appendStringInfoString(buf, "SELECT ");
|
|
|
|
if (is_subquery)
|
|
{
|
|
/*
|
|
* For a relation that is deparsed as a subquery, emit expressions
|
|
* specified in the relation's reltarget. Note that since this is for
|
|
* the subquery, no need to care about *retrieved_attrs.
|
|
*/
|
|
deparseSubqueryTargetList(context);
|
|
}
|
|
else if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
|
|
{
|
|
/*
|
|
* For a join or upper relation the input tlist gives the list of
|
|
* columns required to be fetched from the foreign server.
|
|
*/
|
|
deparseExplicitTargetList(tlist, false, retrieved_attrs, context);
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* For a base relation fpinfo->attrs_used gives the list of columns
|
|
* required to be fetched from the foreign server.
|
|
*/
|
|
RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
|
|
|
|
/*
|
|
* Core code already has some lock on each rel being planned, so we
|
|
* can use NoLock here.
|
|
*/
|
|
Relation rel = heap_open(rte->relid, NoLock);
|
|
|
|
deparseTargetList(buf, rte, foreignrel->relid, rel, false,
|
|
fpinfo->attrs_used, false, retrieved_attrs);
|
|
heap_close(rel, NoLock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Construct a FROM clause and, if needed, a WHERE clause, and append those to
|
|
* "buf".
|
|
*
|
|
* quals is the list of clauses to be included in the WHERE clause.
|
|
* (These may or may not include RestrictInfo decoration.)
|
|
*/
|
|
static void
|
|
deparseFromExpr(List *quals, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
RelOptInfo *scanrel = context->scanrel;
|
|
|
|
/* For upper relations, scanrel must be either a joinrel or a baserel */
|
|
Assert(!IS_UPPER_REL(context->foreignrel) ||
|
|
IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
|
|
|
|
/* Construct FROM clause */
|
|
appendStringInfoString(buf, " FROM ");
|
|
deparseFromExprForRel(buf, context->root, scanrel,
|
|
(bms_membership(scanrel->relids) == BMS_MULTIPLE),
|
|
(Index) 0, NULL, context->params_list);
|
|
|
|
/* Construct WHERE clause */
|
|
if (quals != NIL)
|
|
{
|
|
appendStringInfoString(buf, " WHERE ");
|
|
appendConditions(quals, context);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Emit a target list that retrieves the columns specified in attrs_used.
|
|
* This is used for both SELECT and RETURNING targetlists; the is_returning
|
|
* parameter is true only for a RETURNING targetlist.
|
|
*
|
|
* The tlist text is appended to buf, and we also create an integer List
|
|
* of the columns being retrieved, which is returned to *retrieved_attrs.
|
|
*
|
|
* If qualify_col is true, add relation alias before the column name.
|
|
*/
|
|
static void
|
|
deparseTargetList(StringInfo buf,
|
|
RangeTblEntry *rte,
|
|
Index rtindex,
|
|
Relation rel,
|
|
bool is_returning,
|
|
Bitmapset *attrs_used,
|
|
bool qualify_col,
|
|
List **retrieved_attrs)
|
|
{
|
|
TupleDesc tupdesc = RelationGetDescr(rel);
|
|
bool have_wholerow;
|
|
bool first;
|
|
int i;
|
|
|
|
*retrieved_attrs = NIL;
|
|
|
|
/* If there's a whole-row reference, we'll need all the columns. */
|
|
have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
|
|
attrs_used);
|
|
|
|
first = true;
|
|
for (i = 1; i <= tupdesc->natts; i++)
|
|
{
|
|
Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
|
|
|
|
/* Ignore dropped attributes. */
|
|
if (attr->attisdropped)
|
|
continue;
|
|
|
|
if (have_wholerow ||
|
|
bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
|
|
attrs_used))
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
else if (is_returning)
|
|
appendStringInfoString(buf, " RETURNING ");
|
|
first = false;
|
|
|
|
deparseColumnRef(buf, rtindex, i, rte, qualify_col);
|
|
|
|
*retrieved_attrs = lappend_int(*retrieved_attrs, i);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Add ctid if needed. We currently don't support retrieving any other
|
|
* system columns.
|
|
*/
|
|
if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
|
|
attrs_used))
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
else if (is_returning)
|
|
appendStringInfoString(buf, " RETURNING ");
|
|
first = false;
|
|
|
|
if (qualify_col)
|
|
ADD_REL_QUALIFIER(buf, rtindex);
|
|
appendStringInfoString(buf, "ctid");
|
|
|
|
*retrieved_attrs = lappend_int(*retrieved_attrs,
|
|
SelfItemPointerAttributeNumber);
|
|
}
|
|
|
|
/* Don't generate bad syntax if no undropped columns */
|
|
if (first && !is_returning)
|
|
appendStringInfoString(buf, "NULL");
|
|
}
|
|
|
|
/*
|
|
* Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
|
|
* given relation (context->scanrel).
|
|
*/
|
|
static void
|
|
deparseLockingClause(deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
PlannerInfo *root = context->root;
|
|
RelOptInfo *rel = context->scanrel;
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
|
|
int relid = -1;
|
|
|
|
while ((relid = bms_next_member(rel->relids, relid)) >= 0)
|
|
{
|
|
/*
|
|
* Ignore relation if it appears in a lower subquery. Locking clause
|
|
* for such a relation is included in the subquery if necessary.
|
|
*/
|
|
if (bms_is_member(relid, fpinfo->lower_subquery_rels))
|
|
continue;
|
|
|
|
/*
|
|
* Add FOR UPDATE/SHARE if appropriate. We apply locking during the
|
|
* initial row fetch, rather than later on as is done for local
|
|
* tables. The extra roundtrips involved in trying to duplicate the
|
|
* local semantics exactly don't seem worthwhile (see also comments
|
|
* for RowMarkType).
|
|
*
|
|
* Note: because we actually run the query as a cursor, this assumes
|
|
* that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
|
|
* before 8.3.
|
|
*/
|
|
if (relid == root->parse->resultRelation &&
|
|
(root->parse->commandType == CMD_UPDATE ||
|
|
root->parse->commandType == CMD_DELETE))
|
|
{
|
|
/* Relation is UPDATE/DELETE target, so use FOR UPDATE */
|
|
appendStringInfoString(buf, " FOR UPDATE");
|
|
|
|
/* Add the relation alias if we are here for a join relation */
|
|
if (IS_JOIN_REL(rel))
|
|
appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
|
|
}
|
|
else
|
|
{
|
|
PlanRowMark *rc = get_plan_rowmark(root->rowMarks, relid);
|
|
|
|
if (rc)
|
|
{
|
|
/*
|
|
* Relation is specified as a FOR UPDATE/SHARE target, so
|
|
* handle that. (But we could also see LCS_NONE, meaning this
|
|
* isn't a target relation after all.)
|
|
*
|
|
* For now, just ignore any [NO] KEY specification, since (a)
|
|
* it's not clear what that means for a remote table that we
|
|
* don't have complete information about, and (b) it wouldn't
|
|
* work anyway on older remote servers. Likewise, we don't
|
|
* worry about NOWAIT.
|
|
*/
|
|
switch (rc->strength)
|
|
{
|
|
case LCS_NONE:
|
|
/* No locking needed */
|
|
break;
|
|
case LCS_FORKEYSHARE:
|
|
case LCS_FORSHARE:
|
|
appendStringInfoString(buf, " FOR SHARE");
|
|
break;
|
|
case LCS_FORNOKEYUPDATE:
|
|
case LCS_FORUPDATE:
|
|
appendStringInfoString(buf, " FOR UPDATE");
|
|
break;
|
|
}
|
|
|
|
/* Add the relation alias if we are here for a join relation */
|
|
if (bms_membership(rel->relids) == BMS_MULTIPLE &&
|
|
rc->strength != LCS_NONE)
|
|
appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse conditions from the provided list and append them to buf.
|
|
*
|
|
* The conditions in the list are assumed to be ANDed. This function is used to
|
|
* deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
|
|
*
|
|
* Depending on the caller, the list elements might be either RestrictInfos
|
|
* or bare clauses.
|
|
*/
|
|
static void
|
|
appendConditions(List *exprs, deparse_expr_cxt *context)
|
|
{
|
|
int nestlevel;
|
|
ListCell *lc;
|
|
bool is_first = true;
|
|
StringInfo buf = context->buf;
|
|
|
|
/* Make sure any constants in the exprs are printed portably */
|
|
nestlevel = set_transmission_modes();
|
|
|
|
foreach(lc, exprs)
|
|
{
|
|
Expr *expr = (Expr *) lfirst(lc);
|
|
|
|
/* Extract clause from RestrictInfo, if required */
|
|
if (IsA(expr, RestrictInfo))
|
|
expr = ((RestrictInfo *) expr)->clause;
|
|
|
|
/* Connect expressions with "AND" and parenthesize each condition. */
|
|
if (!is_first)
|
|
appendStringInfoString(buf, " AND ");
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(expr, context);
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
is_first = false;
|
|
}
|
|
|
|
reset_transmission_modes(nestlevel);
|
|
}
|
|
|
|
/* Output join name for given join type */
|
|
const char *
|
|
get_jointype_name(JoinType jointype)
|
|
{
|
|
switch (jointype)
|
|
{
|
|
case JOIN_INNER:
|
|
return "INNER";
|
|
|
|
case JOIN_LEFT:
|
|
return "LEFT";
|
|
|
|
case JOIN_RIGHT:
|
|
return "RIGHT";
|
|
|
|
case JOIN_FULL:
|
|
return "FULL";
|
|
|
|
default:
|
|
/* Shouldn't come here, but protect from buggy code. */
|
|
elog(ERROR, "unsupported join type %d", jointype);
|
|
}
|
|
|
|
/* Keep compiler happy */
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Deparse given targetlist and append it to context->buf.
|
|
*
|
|
* tlist is list of TargetEntry's which in turn contain Var nodes.
|
|
*
|
|
* retrieved_attrs is the list of continuously increasing integers starting
|
|
* from 1. It has same number of entries as tlist.
|
|
*
|
|
* This is used for both SELECT and RETURNING targetlists; the is_returning
|
|
* parameter is true only for a RETURNING targetlist.
|
|
*/
|
|
static void
|
|
deparseExplicitTargetList(List *tlist,
|
|
bool is_returning,
|
|
List **retrieved_attrs,
|
|
deparse_expr_cxt *context)
|
|
{
|
|
ListCell *lc;
|
|
StringInfo buf = context->buf;
|
|
int i = 0;
|
|
|
|
*retrieved_attrs = NIL;
|
|
|
|
foreach(lc, tlist)
|
|
{
|
|
TargetEntry *tle = lfirst_node(TargetEntry, lc);
|
|
|
|
if (i > 0)
|
|
appendStringInfoString(buf, ", ");
|
|
else if (is_returning)
|
|
appendStringInfoString(buf, " RETURNING ");
|
|
|
|
deparseExpr((Expr *) tle->expr, context);
|
|
|
|
*retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
|
|
i++;
|
|
}
|
|
|
|
if (i == 0 && !is_returning)
|
|
appendStringInfoString(buf, "NULL");
|
|
}
|
|
|
|
/*
|
|
* Emit expressions specified in the given relation's reltarget.
|
|
*
|
|
* This is used for deparsing the given relation as a subquery.
|
|
*/
|
|
static void
|
|
deparseSubqueryTargetList(deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
RelOptInfo *foreignrel = context->foreignrel;
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
/* Should only be called in these cases. */
|
|
Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
|
|
|
|
first = true;
|
|
foreach(lc, foreignrel->reltarget->exprs)
|
|
{
|
|
Node *node = (Node *) lfirst(lc);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseExpr((Expr *) node, context);
|
|
}
|
|
|
|
/* Don't generate bad syntax if no expressions */
|
|
if (first)
|
|
appendStringInfoString(buf, "NULL");
|
|
}
|
|
|
|
/*
|
|
* Construct FROM clause for given relation
|
|
*
|
|
* The function constructs ... JOIN ... ON ... for join relation. For a base
|
|
* relation it just returns schema-qualified tablename, with the appropriate
|
|
* alias if so requested.
|
|
*
|
|
* 'ignore_rel' is either zero or the RT index of a target relation. In the
|
|
* latter case the function constructs FROM clause of UPDATE or USING clause
|
|
* of DELETE; it deparses the join relation as if the relation never contained
|
|
* the target relation, and creates a List of conditions to be deparsed into
|
|
* the top-level WHERE clause, which is returned to *ignore_conds.
|
|
*/
|
|
static void
|
|
deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
|
|
bool use_alias, Index ignore_rel, List **ignore_conds,
|
|
List **params_list)
|
|
{
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
|
|
if (IS_JOIN_REL(foreignrel))
|
|
{
|
|
StringInfoData join_sql_o;
|
|
StringInfoData join_sql_i;
|
|
RelOptInfo *outerrel = fpinfo->outerrel;
|
|
RelOptInfo *innerrel = fpinfo->innerrel;
|
|
bool outerrel_is_target = false;
|
|
bool innerrel_is_target = false;
|
|
|
|
if (ignore_rel > 0 && bms_is_member(ignore_rel, foreignrel->relids))
|
|
{
|
|
/*
|
|
* If this is an inner join, add joinclauses to *ignore_conds and
|
|
* set it to empty so that those can be deparsed into the WHERE
|
|
* clause. Note that since the target relation can never be
|
|
* within the nullable side of an outer join, those could safely
|
|
* be pulled up into the WHERE clause (see foreign_join_ok()).
|
|
* Note also that since the target relation is only inner-joined
|
|
* to any other relation in the query, all conditions in the join
|
|
* tree mentioning the target relation could be deparsed into the
|
|
* WHERE clause by doing this recursively.
|
|
*/
|
|
if (fpinfo->jointype == JOIN_INNER)
|
|
{
|
|
*ignore_conds = list_concat(*ignore_conds,
|
|
list_copy(fpinfo->joinclauses));
|
|
fpinfo->joinclauses = NIL;
|
|
}
|
|
|
|
/*
|
|
* Check if either of the input relations is the target relation.
|
|
*/
|
|
if (outerrel->relid == ignore_rel)
|
|
outerrel_is_target = true;
|
|
else if (innerrel->relid == ignore_rel)
|
|
innerrel_is_target = true;
|
|
}
|
|
|
|
/* Deparse outer relation if not the target relation. */
|
|
if (!outerrel_is_target)
|
|
{
|
|
initStringInfo(&join_sql_o);
|
|
deparseRangeTblRef(&join_sql_o, root, outerrel,
|
|
fpinfo->make_outerrel_subquery,
|
|
ignore_rel, ignore_conds, params_list);
|
|
|
|
/*
|
|
* If inner relation is the target relation, skip deparsing it.
|
|
* Note that since the join of the target relation with any other
|
|
* relation in the query is an inner join and can never be within
|
|
* the nullable side of an outer join, the join could be
|
|
* interchanged with higher-level joins (cf. identity 1 on outer
|
|
* join reordering shown in src/backend/optimizer/README), which
|
|
* means it's safe to skip the target-relation deparsing here.
|
|
*/
|
|
if (innerrel_is_target)
|
|
{
|
|
Assert(fpinfo->jointype == JOIN_INNER);
|
|
Assert(fpinfo->joinclauses == NIL);
|
|
appendStringInfo(buf, "%s", join_sql_o.data);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Deparse inner relation if not the target relation. */
|
|
if (!innerrel_is_target)
|
|
{
|
|
initStringInfo(&join_sql_i);
|
|
deparseRangeTblRef(&join_sql_i, root, innerrel,
|
|
fpinfo->make_innerrel_subquery,
|
|
ignore_rel, ignore_conds, params_list);
|
|
|
|
/*
|
|
* If outer relation is the target relation, skip deparsing it.
|
|
* See the above note about safety.
|
|
*/
|
|
if (outerrel_is_target)
|
|
{
|
|
Assert(fpinfo->jointype == JOIN_INNER);
|
|
Assert(fpinfo->joinclauses == NIL);
|
|
appendStringInfo(buf, "%s", join_sql_i.data);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Neither of the relations is the target relation. */
|
|
Assert(!outerrel_is_target && !innerrel_is_target);
|
|
|
|
/*
|
|
* For a join relation FROM clause entry is deparsed as
|
|
*
|
|
* ((outer relation) <join type> (inner relation) ON (joinclauses))
|
|
*/
|
|
appendStringInfo(buf, "(%s %s JOIN %s ON ", join_sql_o.data,
|
|
get_jointype_name(fpinfo->jointype), join_sql_i.data);
|
|
|
|
/* Append join clause; (TRUE) if no join clause */
|
|
if (fpinfo->joinclauses)
|
|
{
|
|
deparse_expr_cxt context;
|
|
|
|
context.buf = buf;
|
|
context.foreignrel = foreignrel;
|
|
context.scanrel = foreignrel;
|
|
context.root = root;
|
|
context.params_list = params_list;
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
appendConditions(fpinfo->joinclauses, &context);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
else
|
|
appendStringInfoString(buf, "(TRUE)");
|
|
|
|
/* End the FROM clause entry. */
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
else
|
|
{
|
|
RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
|
|
|
|
/*
|
|
* Core code already has some lock on each rel being planned, so we
|
|
* can use NoLock here.
|
|
*/
|
|
Relation rel = heap_open(rte->relid, NoLock);
|
|
|
|
deparseRelation(buf, rel);
|
|
|
|
/*
|
|
* Add a unique alias to avoid any conflict in relation names due to
|
|
* pulled up subqueries in the query being built for a pushed down
|
|
* join.
|
|
*/
|
|
if (use_alias)
|
|
appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, foreignrel->relid);
|
|
|
|
heap_close(rel, NoLock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Append FROM clause entry for the given relation into buf.
|
|
*/
|
|
static void
|
|
deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
|
|
bool make_subquery, Index ignore_rel, List **ignore_conds,
|
|
List **params_list)
|
|
{
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
|
|
/* Should only be called in these cases. */
|
|
Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
|
|
|
|
Assert(fpinfo->local_conds == NIL);
|
|
|
|
/* If make_subquery is true, deparse the relation as a subquery. */
|
|
if (make_subquery)
|
|
{
|
|
List *retrieved_attrs;
|
|
int ncols;
|
|
|
|
/*
|
|
* The given relation shouldn't contain the target relation, because
|
|
* this should only happen for input relations for a full join, and
|
|
* such relations can never contain an UPDATE/DELETE target.
|
|
*/
|
|
Assert(ignore_rel == 0 ||
|
|
!bms_is_member(ignore_rel, foreignrel->relids));
|
|
|
|
/* Deparse the subquery representing the relation. */
|
|
appendStringInfoChar(buf, '(');
|
|
deparseSelectStmtForRel(buf, root, foreignrel, NIL,
|
|
fpinfo->remote_conds, NIL, true,
|
|
&retrieved_attrs, params_list);
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
/* Append the relation alias. */
|
|
appendStringInfo(buf, " %s%d", SUBQUERY_REL_ALIAS_PREFIX,
|
|
fpinfo->relation_index);
|
|
|
|
/*
|
|
* Append the column aliases if needed. Note that the subquery emits
|
|
* expressions specified in the relation's reltarget (see
|
|
* deparseSubqueryTargetList).
|
|
*/
|
|
ncols = list_length(foreignrel->reltarget->exprs);
|
|
if (ncols > 0)
|
|
{
|
|
int i;
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
for (i = 1; i <= ncols; i++)
|
|
{
|
|
if (i > 1)
|
|
appendStringInfoString(buf, ", ");
|
|
|
|
appendStringInfo(buf, "%s%d", SUBQUERY_COL_ALIAS_PREFIX, i);
|
|
}
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
}
|
|
else
|
|
deparseFromExprForRel(buf, root, foreignrel, true, ignore_rel,
|
|
ignore_conds, params_list);
|
|
}
|
|
|
|
/*
|
|
* deparse remote INSERT statement
|
|
*
|
|
* The statement text is appended to buf, and we also create an integer List
|
|
* of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
|
|
* which is returned to *retrieved_attrs.
|
|
*/
|
|
void
|
|
deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
|
|
Index rtindex, Relation rel,
|
|
List *targetAttrs, bool doNothing,
|
|
List *withCheckOptionList, List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
AttrNumber pindex;
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
appendStringInfoString(buf, "INSERT INTO ");
|
|
deparseRelation(buf, rel);
|
|
|
|
if (targetAttrs)
|
|
{
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
first = true;
|
|
foreach(lc, targetAttrs)
|
|
{
|
|
int attnum = lfirst_int(lc);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseColumnRef(buf, rtindex, attnum, rte, false);
|
|
}
|
|
|
|
appendStringInfoString(buf, ") VALUES (");
|
|
|
|
pindex = 1;
|
|
first = true;
|
|
foreach(lc, targetAttrs)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
appendStringInfo(buf, "$%d", pindex);
|
|
pindex++;
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
else
|
|
appendStringInfoString(buf, " DEFAULT VALUES");
|
|
|
|
if (doNothing)
|
|
appendStringInfoString(buf, " ON CONFLICT DO NOTHING");
|
|
|
|
deparseReturningList(buf, rte, rtindex, rel,
|
|
rel->trigdesc && rel->trigdesc->trig_insert_after_row,
|
|
withCheckOptionList, returningList, retrieved_attrs);
|
|
}
|
|
|
|
/*
|
|
* deparse remote UPDATE statement
|
|
*
|
|
* The statement text is appended to buf, and we also create an integer List
|
|
* of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
|
|
* which is returned to *retrieved_attrs.
|
|
*/
|
|
void
|
|
deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
|
|
Index rtindex, Relation rel,
|
|
List *targetAttrs,
|
|
List *withCheckOptionList, List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
AttrNumber pindex;
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
appendStringInfoString(buf, "UPDATE ");
|
|
deparseRelation(buf, rel);
|
|
appendStringInfoString(buf, " SET ");
|
|
|
|
pindex = 2; /* ctid is always the first param */
|
|
first = true;
|
|
foreach(lc, targetAttrs)
|
|
{
|
|
int attnum = lfirst_int(lc);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseColumnRef(buf, rtindex, attnum, rte, false);
|
|
appendStringInfo(buf, " = $%d", pindex);
|
|
pindex++;
|
|
}
|
|
appendStringInfoString(buf, " WHERE ctid = $1");
|
|
|
|
deparseReturningList(buf, rte, rtindex, rel,
|
|
rel->trigdesc && rel->trigdesc->trig_update_after_row,
|
|
withCheckOptionList, returningList, retrieved_attrs);
|
|
}
|
|
|
|
/*
|
|
* deparse remote UPDATE statement
|
|
*
|
|
* 'buf' is the output buffer to append the statement to
|
|
* 'rtindex' is the RT index of the associated target relation
|
|
* 'rel' is the relation descriptor for the target relation
|
|
* 'foreignrel' is the RelOptInfo for the target relation or the join relation
|
|
* containing all base relations in the query
|
|
* 'targetlist' is the tlist of the underlying foreign-scan plan node
|
|
* 'targetAttrs' is the target columns of the UPDATE
|
|
* 'remote_conds' is the qual clauses that must be evaluated remotely
|
|
* '*params_list' is an output list of exprs that will become remote Params
|
|
* 'returningList' is the RETURNING targetlist
|
|
* '*retrieved_attrs' is an output list of integers of columns being retrieved
|
|
* by RETURNING (if any)
|
|
*/
|
|
void
|
|
deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
|
|
Index rtindex, Relation rel,
|
|
RelOptInfo *foreignrel,
|
|
List *targetlist,
|
|
List *targetAttrs,
|
|
List *remote_conds,
|
|
List **params_list,
|
|
List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
deparse_expr_cxt context;
|
|
int nestlevel;
|
|
bool first;
|
|
ListCell *lc;
|
|
RangeTblEntry *rte = planner_rt_fetch(rtindex, root);
|
|
|
|
/* Set up context struct for recursion */
|
|
context.root = root;
|
|
context.foreignrel = foreignrel;
|
|
context.scanrel = foreignrel;
|
|
context.buf = buf;
|
|
context.params_list = params_list;
|
|
|
|
appendStringInfoString(buf, "UPDATE ");
|
|
deparseRelation(buf, rel);
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
|
|
appendStringInfoString(buf, " SET ");
|
|
|
|
/* Make sure any constants in the exprs are printed portably */
|
|
nestlevel = set_transmission_modes();
|
|
|
|
first = true;
|
|
foreach(lc, targetAttrs)
|
|
{
|
|
int attnum = lfirst_int(lc);
|
|
TargetEntry *tle = get_tle_by_resno(targetlist, attnum);
|
|
|
|
if (!tle)
|
|
elog(ERROR, "attribute number %d not found in UPDATE targetlist",
|
|
attnum);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseColumnRef(buf, rtindex, attnum, rte, false);
|
|
appendStringInfoString(buf, " = ");
|
|
deparseExpr((Expr *) tle->expr, &context);
|
|
}
|
|
|
|
reset_transmission_modes(nestlevel);
|
|
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
{
|
|
List *ignore_conds = NIL;
|
|
|
|
appendStringInfo(buf, " FROM ");
|
|
deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
|
|
&ignore_conds, params_list);
|
|
remote_conds = list_concat(remote_conds, ignore_conds);
|
|
}
|
|
|
|
if (remote_conds)
|
|
{
|
|
appendStringInfoString(buf, " WHERE ");
|
|
appendConditions(remote_conds, &context);
|
|
}
|
|
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
deparseExplicitTargetList(returningList, true, retrieved_attrs,
|
|
&context);
|
|
else
|
|
deparseReturningList(buf, rte, rtindex, rel, false,
|
|
NIL, returningList, retrieved_attrs);
|
|
}
|
|
|
|
/*
|
|
* deparse remote DELETE statement
|
|
*
|
|
* The statement text is appended to buf, and we also create an integer List
|
|
* of the columns being retrieved by RETURNING (if any), which is returned
|
|
* to *retrieved_attrs.
|
|
*/
|
|
void
|
|
deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
|
|
Index rtindex, Relation rel,
|
|
List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
appendStringInfoString(buf, "DELETE FROM ");
|
|
deparseRelation(buf, rel);
|
|
appendStringInfoString(buf, " WHERE ctid = $1");
|
|
|
|
deparseReturningList(buf, rte, rtindex, rel,
|
|
rel->trigdesc && rel->trigdesc->trig_delete_after_row,
|
|
NIL, returningList, retrieved_attrs);
|
|
}
|
|
|
|
/*
|
|
* deparse remote DELETE statement
|
|
*
|
|
* 'buf' is the output buffer to append the statement to
|
|
* 'rtindex' is the RT index of the associated target relation
|
|
* 'rel' is the relation descriptor for the target relation
|
|
* 'foreignrel' is the RelOptInfo for the target relation or the join relation
|
|
* containing all base relations in the query
|
|
* 'remote_conds' is the qual clauses that must be evaluated remotely
|
|
* '*params_list' is an output list of exprs that will become remote Params
|
|
* 'returningList' is the RETURNING targetlist
|
|
* '*retrieved_attrs' is an output list of integers of columns being retrieved
|
|
* by RETURNING (if any)
|
|
*/
|
|
void
|
|
deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
|
|
Index rtindex, Relation rel,
|
|
RelOptInfo *foreignrel,
|
|
List *remote_conds,
|
|
List **params_list,
|
|
List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
deparse_expr_cxt context;
|
|
|
|
/* Set up context struct for recursion */
|
|
context.root = root;
|
|
context.foreignrel = foreignrel;
|
|
context.scanrel = foreignrel;
|
|
context.buf = buf;
|
|
context.params_list = params_list;
|
|
|
|
appendStringInfoString(buf, "DELETE FROM ");
|
|
deparseRelation(buf, rel);
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
|
|
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
{
|
|
List *ignore_conds = NIL;
|
|
|
|
appendStringInfo(buf, " USING ");
|
|
deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
|
|
&ignore_conds, params_list);
|
|
remote_conds = list_concat(remote_conds, ignore_conds);
|
|
}
|
|
|
|
if (remote_conds)
|
|
{
|
|
appendStringInfoString(buf, " WHERE ");
|
|
appendConditions(remote_conds, &context);
|
|
}
|
|
|
|
if (foreignrel->reloptkind == RELOPT_JOINREL)
|
|
deparseExplicitTargetList(returningList, true, retrieved_attrs,
|
|
&context);
|
|
else
|
|
deparseReturningList(buf, planner_rt_fetch(rtindex, root),
|
|
rtindex, rel, false,
|
|
NIL, returningList, retrieved_attrs);
|
|
}
|
|
|
|
/*
|
|
* Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
|
|
*/
|
|
static void
|
|
deparseReturningList(StringInfo buf, RangeTblEntry *rte,
|
|
Index rtindex, Relation rel,
|
|
bool trig_after_row,
|
|
List *withCheckOptionList,
|
|
List *returningList,
|
|
List **retrieved_attrs)
|
|
{
|
|
Bitmapset *attrs_used = NULL;
|
|
|
|
if (trig_after_row)
|
|
{
|
|
/* whole-row reference acquires all non-system columns */
|
|
attrs_used =
|
|
bms_make_singleton(0 - FirstLowInvalidHeapAttributeNumber);
|
|
}
|
|
|
|
if (withCheckOptionList != NIL)
|
|
{
|
|
/*
|
|
* We need the attrs, non-system and system, mentioned in the local
|
|
* query's WITH CHECK OPTION list.
|
|
*
|
|
* Note: we do this to ensure that WCO constraints will be evaluated
|
|
* on the data actually inserted/updated on the remote side, which
|
|
* might differ from the data supplied by the core code, for example
|
|
* as a result of remote triggers.
|
|
*/
|
|
pull_varattnos((Node *) withCheckOptionList, rtindex,
|
|
&attrs_used);
|
|
}
|
|
|
|
if (returningList != NIL)
|
|
{
|
|
/*
|
|
* We need the attrs, non-system and system, mentioned in the local
|
|
* query's RETURNING list.
|
|
*/
|
|
pull_varattnos((Node *) returningList, rtindex,
|
|
&attrs_used);
|
|
}
|
|
|
|
if (attrs_used != NULL)
|
|
deparseTargetList(buf, rte, rtindex, rel, true, attrs_used, false,
|
|
retrieved_attrs);
|
|
else
|
|
*retrieved_attrs = NIL;
|
|
}
|
|
|
|
/*
|
|
* Construct SELECT statement to acquire size in blocks of given relation.
|
|
*
|
|
* Note: we use local definition of block size, not remote definition.
|
|
* This is perhaps debatable.
|
|
*
|
|
* Note: pg_relation_size() exists in 8.1 and later.
|
|
*/
|
|
void
|
|
deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
|
|
{
|
|
StringInfoData relname;
|
|
|
|
/* We'll need the remote relation name as a literal. */
|
|
initStringInfo(&relname);
|
|
deparseRelation(&relname, rel);
|
|
|
|
appendStringInfoString(buf, "SELECT pg_catalog.pg_relation_size(");
|
|
deparseStringLiteral(buf, relname.data);
|
|
appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
|
|
}
|
|
|
|
/*
|
|
* Construct SELECT statement to acquire sample rows of given relation.
|
|
*
|
|
* SELECT command is appended to buf, and list of columns retrieved
|
|
* is returned to *retrieved_attrs.
|
|
*/
|
|
void
|
|
deparseAnalyzeSql(StringInfo buf, Relation rel, List **retrieved_attrs)
|
|
{
|
|
Oid relid = RelationGetRelid(rel);
|
|
TupleDesc tupdesc = RelationGetDescr(rel);
|
|
int i;
|
|
char *colname;
|
|
List *options;
|
|
ListCell *lc;
|
|
bool first = true;
|
|
|
|
*retrieved_attrs = NIL;
|
|
|
|
appendStringInfoString(buf, "SELECT ");
|
|
for (i = 0; i < tupdesc->natts; i++)
|
|
{
|
|
/* Ignore dropped columns. */
|
|
if (TupleDescAttr(tupdesc, i)->attisdropped)
|
|
continue;
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
/* Use attribute name or column_name option. */
|
|
colname = NameStr(TupleDescAttr(tupdesc, i)->attname);
|
|
options = GetForeignColumnOptions(relid, i + 1);
|
|
|
|
foreach(lc, options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "column_name") == 0)
|
|
{
|
|
colname = defGetString(def);
|
|
break;
|
|
}
|
|
}
|
|
|
|
appendStringInfoString(buf, quote_identifier(colname));
|
|
|
|
*retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
|
|
}
|
|
|
|
/* Don't generate bad syntax for zero-column relation. */
|
|
if (first)
|
|
appendStringInfoString(buf, "NULL");
|
|
|
|
/*
|
|
* Construct FROM clause
|
|
*/
|
|
appendStringInfoString(buf, " FROM ");
|
|
deparseRelation(buf, rel);
|
|
}
|
|
|
|
/*
|
|
* Construct name to use for given column, and emit it into buf.
|
|
* If it has a column_name FDW option, use that instead of attribute name.
|
|
*
|
|
* If qualify_col is true, qualify column name with the alias of relation.
|
|
*/
|
|
static void
|
|
deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte,
|
|
bool qualify_col)
|
|
{
|
|
/* We support fetching the remote side's CTID and OID. */
|
|
if (varattno == SelfItemPointerAttributeNumber)
|
|
{
|
|
if (qualify_col)
|
|
ADD_REL_QUALIFIER(buf, varno);
|
|
appendStringInfoString(buf, "ctid");
|
|
}
|
|
else if (varattno < 0)
|
|
{
|
|
/*
|
|
* All other system attributes are fetched as 0, except for table OID,
|
|
* which is fetched as the local table OID. However, we must be
|
|
* careful; the table could be beneath an outer join, in which case it
|
|
* must go to NULL whenever the rest of the row does.
|
|
*/
|
|
Oid fetchval = 0;
|
|
|
|
if (varattno == TableOidAttributeNumber)
|
|
fetchval = rte->relid;
|
|
|
|
if (qualify_col)
|
|
{
|
|
appendStringInfoString(buf, "CASE WHEN (");
|
|
ADD_REL_QUALIFIER(buf, varno);
|
|
appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
|
|
}
|
|
else
|
|
appendStringInfo(buf, "%u", fetchval);
|
|
}
|
|
else if (varattno == 0)
|
|
{
|
|
/* Whole row reference */
|
|
Relation rel;
|
|
Bitmapset *attrs_used;
|
|
|
|
/* Required only to be passed down to deparseTargetList(). */
|
|
List *retrieved_attrs;
|
|
|
|
/*
|
|
* The lock on the relation will be held by upper callers, so it's
|
|
* fine to open it with no lock here.
|
|
*/
|
|
rel = heap_open(rte->relid, NoLock);
|
|
|
|
/*
|
|
* The local name of the foreign table can not be recognized by the
|
|
* foreign server and the table it references on foreign server might
|
|
* have different column ordering or different columns than those
|
|
* declared locally. Hence we have to deparse whole-row reference as
|
|
* ROW(columns referenced locally). Construct this by deparsing a
|
|
* "whole row" attribute.
|
|
*/
|
|
attrs_used = bms_add_member(NULL,
|
|
0 - FirstLowInvalidHeapAttributeNumber);
|
|
|
|
/*
|
|
* In case the whole-row reference is under an outer join then it has
|
|
* to go NULL whenever the rest of the row goes NULL. Deparsing a join
|
|
* query would always involve multiple relations, thus qualify_col
|
|
* would be true.
|
|
*/
|
|
if (qualify_col)
|
|
{
|
|
appendStringInfoString(buf, "CASE WHEN (");
|
|
ADD_REL_QUALIFIER(buf, varno);
|
|
appendStringInfoString(buf, "*)::text IS NOT NULL THEN ");
|
|
}
|
|
|
|
appendStringInfoString(buf, "ROW(");
|
|
deparseTargetList(buf, rte, varno, rel, false, attrs_used, qualify_col,
|
|
&retrieved_attrs);
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
/* Complete the CASE WHEN statement started above. */
|
|
if (qualify_col)
|
|
appendStringInfoString(buf, " END");
|
|
|
|
heap_close(rel, NoLock);
|
|
bms_free(attrs_used);
|
|
}
|
|
else
|
|
{
|
|
char *colname = NULL;
|
|
List *options;
|
|
ListCell *lc;
|
|
|
|
/* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
|
|
Assert(!IS_SPECIAL_VARNO(varno));
|
|
|
|
/*
|
|
* If it's a column of a foreign table, and it has the column_name FDW
|
|
* option, use that value.
|
|
*/
|
|
options = GetForeignColumnOptions(rte->relid, varattno);
|
|
foreach(lc, options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "column_name") == 0)
|
|
{
|
|
colname = defGetString(def);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If it's a column of a regular table or it doesn't have column_name
|
|
* FDW option, use attribute name.
|
|
*/
|
|
if (colname == NULL)
|
|
colname = get_attname(rte->relid, varattno, false);
|
|
|
|
if (qualify_col)
|
|
ADD_REL_QUALIFIER(buf, varno);
|
|
|
|
appendStringInfoString(buf, quote_identifier(colname));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Append remote name of specified foreign table to buf.
|
|
* Use value of table_name FDW option (if any) instead of relation's name.
|
|
* Similarly, schema_name FDW option overrides schema name.
|
|
*/
|
|
static void
|
|
deparseRelation(StringInfo buf, Relation rel)
|
|
{
|
|
ForeignTable *table;
|
|
const char *nspname = NULL;
|
|
const char *relname = NULL;
|
|
ListCell *lc;
|
|
|
|
/* obtain additional catalog information. */
|
|
table = GetForeignTable(RelationGetRelid(rel));
|
|
|
|
/*
|
|
* Use value of FDW options if any, instead of the name of object itself.
|
|
*/
|
|
foreach(lc, table->options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "schema_name") == 0)
|
|
nspname = defGetString(def);
|
|
else if (strcmp(def->defname, "table_name") == 0)
|
|
relname = defGetString(def);
|
|
}
|
|
|
|
/*
|
|
* Note: we could skip printing the schema name if it's pg_catalog, but
|
|
* that doesn't seem worth the trouble.
|
|
*/
|
|
if (nspname == NULL)
|
|
nspname = get_namespace_name(RelationGetNamespace(rel));
|
|
if (relname == NULL)
|
|
relname = RelationGetRelationName(rel);
|
|
|
|
appendStringInfo(buf, "%s.%s",
|
|
quote_identifier(nspname), quote_identifier(relname));
|
|
}
|
|
|
|
/*
|
|
* Append a SQL string literal representing "val" to buf.
|
|
*/
|
|
void
|
|
deparseStringLiteral(StringInfo buf, const char *val)
|
|
{
|
|
const char *valptr;
|
|
|
|
/*
|
|
* Rather than making assumptions about the remote server's value of
|
|
* standard_conforming_strings, always use E'foo' syntax if there are any
|
|
* backslashes. This will fail on remote servers before 8.1, but those
|
|
* are long out of support.
|
|
*/
|
|
if (strchr(val, '\\') != NULL)
|
|
appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
|
|
appendStringInfoChar(buf, '\'');
|
|
for (valptr = val; *valptr; valptr++)
|
|
{
|
|
char ch = *valptr;
|
|
|
|
if (SQL_STR_DOUBLE(ch, true))
|
|
appendStringInfoChar(buf, ch);
|
|
appendStringInfoChar(buf, ch);
|
|
}
|
|
appendStringInfoChar(buf, '\'');
|
|
}
|
|
|
|
/*
|
|
* Deparse given expression into context->buf.
|
|
*
|
|
* This function must support all the same node types that foreign_expr_walker
|
|
* accepts.
|
|
*
|
|
* Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
|
|
* scheme: anything more complex than a Var, Const, function call or cast
|
|
* should be self-parenthesized.
|
|
*/
|
|
static void
|
|
deparseExpr(Expr *node, deparse_expr_cxt *context)
|
|
{
|
|
if (node == NULL)
|
|
return;
|
|
|
|
switch (nodeTag(node))
|
|
{
|
|
case T_Var:
|
|
deparseVar((Var *) node, context);
|
|
break;
|
|
case T_Const:
|
|
deparseConst((Const *) node, context, 0);
|
|
break;
|
|
case T_Param:
|
|
deparseParam((Param *) node, context);
|
|
break;
|
|
case T_ArrayRef:
|
|
deparseArrayRef((ArrayRef *) node, context);
|
|
break;
|
|
case T_FuncExpr:
|
|
deparseFuncExpr((FuncExpr *) node, context);
|
|
break;
|
|
case T_OpExpr:
|
|
deparseOpExpr((OpExpr *) node, context);
|
|
break;
|
|
case T_DistinctExpr:
|
|
deparseDistinctExpr((DistinctExpr *) node, context);
|
|
break;
|
|
case T_ScalarArrayOpExpr:
|
|
deparseScalarArrayOpExpr((ScalarArrayOpExpr *) node, context);
|
|
break;
|
|
case T_RelabelType:
|
|
deparseRelabelType((RelabelType *) node, context);
|
|
break;
|
|
case T_BoolExpr:
|
|
deparseBoolExpr((BoolExpr *) node, context);
|
|
break;
|
|
case T_NullTest:
|
|
deparseNullTest((NullTest *) node, context);
|
|
break;
|
|
case T_ArrayExpr:
|
|
deparseArrayExpr((ArrayExpr *) node, context);
|
|
break;
|
|
case T_Aggref:
|
|
deparseAggref((Aggref *) node, context);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unsupported expression type for deparse: %d",
|
|
(int) nodeTag(node));
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse given Var node into context->buf.
|
|
*
|
|
* If the Var belongs to the foreign relation, just print its remote name.
|
|
* Otherwise, it's effectively a Param (and will in fact be a Param at
|
|
* run time). Handle it the same way we handle plain Params --- see
|
|
* deparseParam for comments.
|
|
*/
|
|
static void
|
|
deparseVar(Var *node, deparse_expr_cxt *context)
|
|
{
|
|
Relids relids = context->scanrel->relids;
|
|
int relno;
|
|
int colno;
|
|
|
|
/* Qualify columns when multiple relations are involved. */
|
|
bool qualify_col = (bms_membership(relids) == BMS_MULTIPLE);
|
|
|
|
/*
|
|
* If the Var belongs to the foreign relation that is deparsed as a
|
|
* subquery, use the relation and column alias to the Var provided by the
|
|
* subquery, instead of the remote name.
|
|
*/
|
|
if (is_subquery_var(node, context->scanrel, &relno, &colno))
|
|
{
|
|
appendStringInfo(context->buf, "%s%d.%s%d",
|
|
SUBQUERY_REL_ALIAS_PREFIX, relno,
|
|
SUBQUERY_COL_ALIAS_PREFIX, colno);
|
|
return;
|
|
}
|
|
|
|
if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
|
|
deparseColumnRef(context->buf, node->varno, node->varattno,
|
|
planner_rt_fetch(node->varno, context->root),
|
|
qualify_col);
|
|
else
|
|
{
|
|
/* Treat like a Param */
|
|
if (context->params_list)
|
|
{
|
|
int pindex = 0;
|
|
ListCell *lc;
|
|
|
|
/* find its index in params_list */
|
|
foreach(lc, *context->params_list)
|
|
{
|
|
pindex++;
|
|
if (equal(node, (Node *) lfirst(lc)))
|
|
break;
|
|
}
|
|
if (lc == NULL)
|
|
{
|
|
/* not in list, so add it */
|
|
pindex++;
|
|
*context->params_list = lappend(*context->params_list, node);
|
|
}
|
|
|
|
printRemoteParam(pindex, node->vartype, node->vartypmod, context);
|
|
}
|
|
else
|
|
{
|
|
printRemotePlaceholder(node->vartype, node->vartypmod, context);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse given constant value into context->buf.
|
|
*
|
|
* This function has to be kept in sync with ruleutils.c's get_const_expr.
|
|
* As for that function, showtype can be -1 to never show "::typename" decoration,
|
|
* or +1 to always show it, or 0 to show it only if the constant wouldn't be assumed
|
|
* to be the right type by default.
|
|
*/
|
|
static void
|
|
deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
Oid typoutput;
|
|
bool typIsVarlena;
|
|
char *extval;
|
|
bool isfloat = false;
|
|
bool needlabel;
|
|
|
|
if (node->constisnull)
|
|
{
|
|
appendStringInfoString(buf, "NULL");
|
|
if (showtype >= 0)
|
|
appendStringInfo(buf, "::%s",
|
|
deparse_type_name(node->consttype,
|
|
node->consttypmod));
|
|
return;
|
|
}
|
|
|
|
getTypeOutputInfo(node->consttype,
|
|
&typoutput, &typIsVarlena);
|
|
extval = OidOutputFunctionCall(typoutput, node->constvalue);
|
|
|
|
switch (node->consttype)
|
|
{
|
|
case INT2OID:
|
|
case INT4OID:
|
|
case INT8OID:
|
|
case OIDOID:
|
|
case FLOAT4OID:
|
|
case FLOAT8OID:
|
|
case NUMERICOID:
|
|
{
|
|
/*
|
|
* No need to quote unless it's a special value such as 'NaN'.
|
|
* See comments in get_const_expr().
|
|
*/
|
|
if (strspn(extval, "0123456789+-eE.") == strlen(extval))
|
|
{
|
|
if (extval[0] == '+' || extval[0] == '-')
|
|
appendStringInfo(buf, "(%s)", extval);
|
|
else
|
|
appendStringInfoString(buf, extval);
|
|
if (strcspn(extval, "eE.") != strlen(extval))
|
|
isfloat = true; /* it looks like a float */
|
|
}
|
|
else
|
|
appendStringInfo(buf, "'%s'", extval);
|
|
}
|
|
break;
|
|
case BITOID:
|
|
case VARBITOID:
|
|
appendStringInfo(buf, "B'%s'", extval);
|
|
break;
|
|
case BOOLOID:
|
|
if (strcmp(extval, "t") == 0)
|
|
appendStringInfoString(buf, "true");
|
|
else
|
|
appendStringInfoString(buf, "false");
|
|
break;
|
|
default:
|
|
deparseStringLiteral(buf, extval);
|
|
break;
|
|
}
|
|
|
|
pfree(extval);
|
|
|
|
if (showtype < 0)
|
|
return;
|
|
|
|
/*
|
|
* For showtype == 0, append ::typename unless the constant will be
|
|
* implicitly typed as the right type when it is read in.
|
|
*
|
|
* XXX this code has to be kept in sync with the behavior of the parser,
|
|
* especially make_const.
|
|
*/
|
|
switch (node->consttype)
|
|
{
|
|
case BOOLOID:
|
|
case INT4OID:
|
|
case UNKNOWNOID:
|
|
needlabel = false;
|
|
break;
|
|
case NUMERICOID:
|
|
needlabel = !isfloat || (node->consttypmod >= 0);
|
|
break;
|
|
default:
|
|
needlabel = true;
|
|
break;
|
|
}
|
|
if (needlabel || showtype > 0)
|
|
appendStringInfo(buf, "::%s",
|
|
deparse_type_name(node->consttype,
|
|
node->consttypmod));
|
|
}
|
|
|
|
/*
|
|
* Deparse given Param node.
|
|
*
|
|
* If we're generating the query "for real", add the Param to
|
|
* context->params_list if it's not already present, and then use its index
|
|
* in that list as the remote parameter number. During EXPLAIN, there's
|
|
* no need to identify a parameter number.
|
|
*/
|
|
static void
|
|
deparseParam(Param *node, deparse_expr_cxt *context)
|
|
{
|
|
if (context->params_list)
|
|
{
|
|
int pindex = 0;
|
|
ListCell *lc;
|
|
|
|
/* find its index in params_list */
|
|
foreach(lc, *context->params_list)
|
|
{
|
|
pindex++;
|
|
if (equal(node, (Node *) lfirst(lc)))
|
|
break;
|
|
}
|
|
if (lc == NULL)
|
|
{
|
|
/* not in list, so add it */
|
|
pindex++;
|
|
*context->params_list = lappend(*context->params_list, node);
|
|
}
|
|
|
|
printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
|
|
}
|
|
else
|
|
{
|
|
printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse an array subscript expression.
|
|
*/
|
|
static void
|
|
deparseArrayRef(ArrayRef *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
ListCell *lowlist_item;
|
|
ListCell *uplist_item;
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/*
|
|
* Deparse referenced array expression first. If that expression includes
|
|
* a cast, we have to parenthesize to prevent the array subscript from
|
|
* being taken as typename decoration. We can avoid that in the typical
|
|
* case of subscripting a Var, but otherwise do it.
|
|
*/
|
|
if (IsA(node->refexpr, Var))
|
|
deparseExpr(node->refexpr, context);
|
|
else
|
|
{
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(node->refexpr, context);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/* Deparse subscript expressions. */
|
|
lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
|
|
foreach(uplist_item, node->refupperindexpr)
|
|
{
|
|
appendStringInfoChar(buf, '[');
|
|
if (lowlist_item)
|
|
{
|
|
deparseExpr(lfirst(lowlist_item), context);
|
|
appendStringInfoChar(buf, ':');
|
|
lowlist_item = lnext(lowlist_item);
|
|
}
|
|
deparseExpr(lfirst(uplist_item), context);
|
|
appendStringInfoChar(buf, ']');
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse a function call.
|
|
*/
|
|
static void
|
|
deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
bool use_variadic;
|
|
bool first;
|
|
ListCell *arg;
|
|
|
|
/*
|
|
* If the function call came from an implicit coercion, then just show the
|
|
* first argument.
|
|
*/
|
|
if (node->funcformat == COERCE_IMPLICIT_CAST)
|
|
{
|
|
deparseExpr((Expr *) linitial(node->args), context);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If the function call came from a cast, then show the first argument
|
|
* plus an explicit cast operation.
|
|
*/
|
|
if (node->funcformat == COERCE_EXPLICIT_CAST)
|
|
{
|
|
Oid rettype = node->funcresulttype;
|
|
int32 coercedTypmod;
|
|
|
|
/* Get the typmod if this is a length-coercion function */
|
|
(void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
|
|
|
|
deparseExpr((Expr *) linitial(node->args), context);
|
|
appendStringInfo(buf, "::%s",
|
|
deparse_type_name(rettype, coercedTypmod));
|
|
return;
|
|
}
|
|
|
|
/* Check if need to print VARIADIC (cf. ruleutils.c) */
|
|
use_variadic = node->funcvariadic;
|
|
|
|
/*
|
|
* Normal function: display as proname(args).
|
|
*/
|
|
appendFunctionName(node->funcid, context);
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* ... and all the arguments */
|
|
first = true;
|
|
foreach(arg, node->args)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
if (use_variadic && lnext(arg) == NULL)
|
|
appendStringInfoString(buf, "VARIADIC ");
|
|
deparseExpr((Expr *) lfirst(arg), context);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse given operator expression. To avoid problems around
|
|
* priority of operations, we always parenthesize the arguments.
|
|
*/
|
|
static void
|
|
deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
HeapTuple tuple;
|
|
Form_pg_operator form;
|
|
char oprkind;
|
|
ListCell *arg;
|
|
|
|
/* Retrieve information about the operator from system catalog. */
|
|
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
|
|
if (!HeapTupleIsValid(tuple))
|
|
elog(ERROR, "cache lookup failed for operator %u", node->opno);
|
|
form = (Form_pg_operator) GETSTRUCT(tuple);
|
|
oprkind = form->oprkind;
|
|
|
|
/* Sanity check. */
|
|
Assert((oprkind == 'r' && list_length(node->args) == 1) ||
|
|
(oprkind == 'l' && list_length(node->args) == 1) ||
|
|
(oprkind == 'b' && list_length(node->args) == 2));
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* Deparse left operand. */
|
|
if (oprkind == 'r' || oprkind == 'b')
|
|
{
|
|
arg = list_head(node->args);
|
|
deparseExpr(lfirst(arg), context);
|
|
appendStringInfoChar(buf, ' ');
|
|
}
|
|
|
|
/* Deparse operator name. */
|
|
deparseOperatorName(buf, form);
|
|
|
|
/* Deparse right operand. */
|
|
if (oprkind == 'l' || oprkind == 'b')
|
|
{
|
|
arg = list_tail(node->args);
|
|
appendStringInfoChar(buf, ' ');
|
|
deparseExpr(lfirst(arg), context);
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
ReleaseSysCache(tuple);
|
|
}
|
|
|
|
/*
|
|
* Print the name of an operator.
|
|
*/
|
|
static void
|
|
deparseOperatorName(StringInfo buf, Form_pg_operator opform)
|
|
{
|
|
char *opname;
|
|
|
|
/* opname is not a SQL identifier, so we should not quote it. */
|
|
opname = NameStr(opform->oprname);
|
|
|
|
/* Print schema name only if it's not pg_catalog */
|
|
if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
|
|
{
|
|
const char *opnspname;
|
|
|
|
opnspname = get_namespace_name(opform->oprnamespace);
|
|
/* Print fully qualified operator name. */
|
|
appendStringInfo(buf, "OPERATOR(%s.%s)",
|
|
quote_identifier(opnspname), opname);
|
|
}
|
|
else
|
|
{
|
|
/* Just print operator name. */
|
|
appendStringInfoString(buf, opname);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse IS DISTINCT FROM.
|
|
*/
|
|
static void
|
|
deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
|
|
Assert(list_length(node->args) == 2);
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(linitial(node->args), context);
|
|
appendStringInfoString(buf, " IS DISTINCT FROM ");
|
|
deparseExpr(lsecond(node->args), context);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse given ScalarArrayOpExpr expression. To avoid problems
|
|
* around priority of operations, we always parenthesize the arguments.
|
|
*/
|
|
static void
|
|
deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
HeapTuple tuple;
|
|
Form_pg_operator form;
|
|
Expr *arg1;
|
|
Expr *arg2;
|
|
|
|
/* Retrieve information about the operator from system catalog. */
|
|
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
|
|
if (!HeapTupleIsValid(tuple))
|
|
elog(ERROR, "cache lookup failed for operator %u", node->opno);
|
|
form = (Form_pg_operator) GETSTRUCT(tuple);
|
|
|
|
/* Sanity check. */
|
|
Assert(list_length(node->args) == 2);
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* Deparse left operand. */
|
|
arg1 = linitial(node->args);
|
|
deparseExpr(arg1, context);
|
|
appendStringInfoChar(buf, ' ');
|
|
|
|
/* Deparse operator name plus decoration. */
|
|
deparseOperatorName(buf, form);
|
|
appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
|
|
|
|
/* Deparse right operand. */
|
|
arg2 = lsecond(node->args);
|
|
deparseExpr(arg2, context);
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
ReleaseSysCache(tuple);
|
|
}
|
|
|
|
/*
|
|
* Deparse a RelabelType (binary-compatible cast) node.
|
|
*/
|
|
static void
|
|
deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
|
|
{
|
|
deparseExpr(node->arg, context);
|
|
if (node->relabelformat != COERCE_IMPLICIT_CAST)
|
|
appendStringInfo(context->buf, "::%s",
|
|
deparse_type_name(node->resulttype,
|
|
node->resulttypmod));
|
|
}
|
|
|
|
/*
|
|
* Deparse a BoolExpr node.
|
|
*/
|
|
static void
|
|
deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
const char *op = NULL; /* keep compiler quiet */
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
switch (node->boolop)
|
|
{
|
|
case AND_EXPR:
|
|
op = "AND";
|
|
break;
|
|
case OR_EXPR:
|
|
op = "OR";
|
|
break;
|
|
case NOT_EXPR:
|
|
appendStringInfoString(buf, "(NOT ");
|
|
deparseExpr(linitial(node->args), context);
|
|
appendStringInfoChar(buf, ')');
|
|
return;
|
|
}
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
first = true;
|
|
foreach(lc, node->args)
|
|
{
|
|
if (!first)
|
|
appendStringInfo(buf, " %s ", op);
|
|
deparseExpr((Expr *) lfirst(lc), context);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse IS [NOT] NULL expression.
|
|
*/
|
|
static void
|
|
deparseNullTest(NullTest *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(node->arg, context);
|
|
|
|
/*
|
|
* For scalar inputs, we prefer to print as IS [NOT] NULL, which is
|
|
* shorter and traditional. If it's a rowtype input but we're applying a
|
|
* scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
|
|
* correct.
|
|
*/
|
|
if (node->argisrow || !type_is_rowtype(exprType((Node *) node->arg)))
|
|
{
|
|
if (node->nulltesttype == IS_NULL)
|
|
appendStringInfoString(buf, " IS NULL)");
|
|
else
|
|
appendStringInfoString(buf, " IS NOT NULL)");
|
|
}
|
|
else
|
|
{
|
|
if (node->nulltesttype == IS_NULL)
|
|
appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
|
|
else
|
|
appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse ARRAY[...] construct.
|
|
*/
|
|
static void
|
|
deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
bool first = true;
|
|
ListCell *lc;
|
|
|
|
appendStringInfoString(buf, "ARRAY[");
|
|
foreach(lc, node->elements)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
deparseExpr(lfirst(lc), context);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ']');
|
|
|
|
/* If the array is empty, we need an explicit cast to the array type. */
|
|
if (node->elements == NIL)
|
|
appendStringInfo(buf, "::%s",
|
|
deparse_type_name(node->array_typeid, -1));
|
|
}
|
|
|
|
/*
|
|
* Deparse an Aggref node.
|
|
*/
|
|
static void
|
|
deparseAggref(Aggref *node, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
bool use_variadic;
|
|
|
|
/* Only basic, non-split aggregation accepted. */
|
|
Assert(node->aggsplit == AGGSPLIT_SIMPLE);
|
|
|
|
/* Check if need to print VARIADIC (cf. ruleutils.c) */
|
|
use_variadic = node->aggvariadic;
|
|
|
|
/* Find aggregate name from aggfnoid which is a pg_proc entry */
|
|
appendFunctionName(node->aggfnoid, context);
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* Add DISTINCT */
|
|
appendStringInfoString(buf, (node->aggdistinct != NIL) ? "DISTINCT " : "");
|
|
|
|
if (AGGKIND_IS_ORDERED_SET(node->aggkind))
|
|
{
|
|
/* Add WITHIN GROUP (ORDER BY ..) */
|
|
ListCell *arg;
|
|
bool first = true;
|
|
|
|
Assert(!node->aggvariadic);
|
|
Assert(node->aggorder != NIL);
|
|
|
|
foreach(arg, node->aggdirectargs)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseExpr((Expr *) lfirst(arg), context);
|
|
}
|
|
|
|
appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
|
|
appendAggOrderBy(node->aggorder, node->args, context);
|
|
}
|
|
else
|
|
{
|
|
/* aggstar can be set only in zero-argument aggregates */
|
|
if (node->aggstar)
|
|
appendStringInfoChar(buf, '*');
|
|
else
|
|
{
|
|
ListCell *arg;
|
|
bool first = true;
|
|
|
|
/* Add all the arguments */
|
|
foreach(arg, node->args)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(arg);
|
|
Node *n = (Node *) tle->expr;
|
|
|
|
if (tle->resjunk)
|
|
continue;
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
/* Add VARIADIC */
|
|
if (use_variadic && lnext(arg) == NULL)
|
|
appendStringInfoString(buf, "VARIADIC ");
|
|
|
|
deparseExpr((Expr *) n, context);
|
|
}
|
|
}
|
|
|
|
/* Add ORDER BY */
|
|
if (node->aggorder != NIL)
|
|
{
|
|
appendStringInfoString(buf, " ORDER BY ");
|
|
appendAggOrderBy(node->aggorder, node->args, context);
|
|
}
|
|
}
|
|
|
|
/* Add FILTER (WHERE ..) */
|
|
if (node->aggfilter != NULL)
|
|
{
|
|
appendStringInfoString(buf, ") FILTER (WHERE ");
|
|
deparseExpr((Expr *) node->aggfilter, context);
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Append ORDER BY within aggregate function.
|
|
*/
|
|
static void
|
|
appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
ListCell *lc;
|
|
bool first = true;
|
|
|
|
foreach(lc, orderList)
|
|
{
|
|
SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
|
|
Node *sortexpr;
|
|
Oid sortcoltype;
|
|
TypeCacheEntry *typentry;
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList,
|
|
false, context);
|
|
sortcoltype = exprType(sortexpr);
|
|
/* See whether operator is default < or > for datatype */
|
|
typentry = lookup_type_cache(sortcoltype,
|
|
TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
|
|
if (srt->sortop == typentry->lt_opr)
|
|
appendStringInfoString(buf, " ASC");
|
|
else if (srt->sortop == typentry->gt_opr)
|
|
appendStringInfoString(buf, " DESC");
|
|
else
|
|
{
|
|
HeapTuple opertup;
|
|
Form_pg_operator operform;
|
|
|
|
appendStringInfoString(buf, " USING ");
|
|
|
|
/* Append operator name. */
|
|
opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(srt->sortop));
|
|
if (!HeapTupleIsValid(opertup))
|
|
elog(ERROR, "cache lookup failed for operator %u", srt->sortop);
|
|
operform = (Form_pg_operator) GETSTRUCT(opertup);
|
|
deparseOperatorName(buf, operform);
|
|
ReleaseSysCache(opertup);
|
|
}
|
|
|
|
if (srt->nulls_first)
|
|
appendStringInfoString(buf, " NULLS FIRST");
|
|
else
|
|
appendStringInfoString(buf, " NULLS LAST");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Print the representation of a parameter to be sent to the remote side.
|
|
*
|
|
* Note: we always label the Param's type explicitly rather than relying on
|
|
* transmitting a numeric type OID in PQexecParams(). This allows us to
|
|
* avoid assuming that types have the same OIDs on the remote side as they
|
|
* do locally --- they need only have the same names.
|
|
*/
|
|
static void
|
|
printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
|
|
deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
char *ptypename = deparse_type_name(paramtype, paramtypmod);
|
|
|
|
appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
|
|
}
|
|
|
|
/*
|
|
* Print the representation of a placeholder for a parameter that will be
|
|
* sent to the remote side at execution time.
|
|
*
|
|
* This is used when we're just trying to EXPLAIN the remote query.
|
|
* We don't have the actual value of the runtime parameter yet, and we don't
|
|
* want the remote planner to generate a plan that depends on such a value
|
|
* anyway. Thus, we can't do something simple like "$1::paramtype".
|
|
* Instead, we emit "((SELECT null::paramtype)::paramtype)".
|
|
* In all extant versions of Postgres, the planner will see that as an unknown
|
|
* constant value, which is what we want. This might need adjustment if we
|
|
* ever make the planner flatten scalar subqueries. Note: the reason for the
|
|
* apparently useless outer cast is to ensure that the representation as a
|
|
* whole will be parsed as an a_expr and not a select_with_parens; the latter
|
|
* would do the wrong thing in the context "x = ANY(...)".
|
|
*/
|
|
static void
|
|
printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
|
|
deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
char *ptypename = deparse_type_name(paramtype, paramtypmod);
|
|
|
|
appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
|
|
}
|
|
|
|
/*
|
|
* Deparse GROUP BY clause.
|
|
*/
|
|
static void
|
|
appendGroupByClause(List *tlist, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
Query *query = context->root->parse;
|
|
ListCell *lc;
|
|
bool first = true;
|
|
|
|
/* Nothing to be done, if there's no GROUP BY clause in the query. */
|
|
if (!query->groupClause)
|
|
return;
|
|
|
|
appendStringInfoString(buf, " GROUP BY ");
|
|
|
|
/*
|
|
* Queries with grouping sets are not pushed down, so we don't expect
|
|
* grouping sets here.
|
|
*/
|
|
Assert(!query->groupingSets);
|
|
|
|
foreach(lc, query->groupClause)
|
|
{
|
|
SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseSortGroupClause(grp->tleSortGroupRef, tlist, true, context);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse ORDER BY clause according to the given pathkeys for given base
|
|
* relation. From given pathkeys expressions belonging entirely to the given
|
|
* base relation are obtained and deparsed.
|
|
*/
|
|
static void
|
|
appendOrderByClause(List *pathkeys, deparse_expr_cxt *context)
|
|
{
|
|
ListCell *lcell;
|
|
int nestlevel;
|
|
char *delim = " ";
|
|
RelOptInfo *baserel = context->scanrel;
|
|
StringInfo buf = context->buf;
|
|
|
|
/* Make sure any constants in the exprs are printed portably */
|
|
nestlevel = set_transmission_modes();
|
|
|
|
appendStringInfoString(buf, " ORDER BY");
|
|
foreach(lcell, pathkeys)
|
|
{
|
|
PathKey *pathkey = lfirst(lcell);
|
|
Expr *em_expr;
|
|
|
|
em_expr = find_em_expr_for_rel(pathkey->pk_eclass, baserel);
|
|
Assert(em_expr != NULL);
|
|
|
|
appendStringInfoString(buf, delim);
|
|
deparseExpr(em_expr, context);
|
|
if (pathkey->pk_strategy == BTLessStrategyNumber)
|
|
appendStringInfoString(buf, " ASC");
|
|
else
|
|
appendStringInfoString(buf, " DESC");
|
|
|
|
if (pathkey->pk_nulls_first)
|
|
appendStringInfoString(buf, " NULLS FIRST");
|
|
else
|
|
appendStringInfoString(buf, " NULLS LAST");
|
|
|
|
delim = ", ";
|
|
}
|
|
reset_transmission_modes(nestlevel);
|
|
}
|
|
|
|
/*
|
|
* appendFunctionName
|
|
* Deparses function name from given function oid.
|
|
*/
|
|
static void
|
|
appendFunctionName(Oid funcid, deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
HeapTuple proctup;
|
|
Form_pg_proc procform;
|
|
const char *proname;
|
|
|
|
proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
|
|
if (!HeapTupleIsValid(proctup))
|
|
elog(ERROR, "cache lookup failed for function %u", funcid);
|
|
procform = (Form_pg_proc) GETSTRUCT(proctup);
|
|
|
|
/* Print schema name only if it's not pg_catalog */
|
|
if (procform->pronamespace != PG_CATALOG_NAMESPACE)
|
|
{
|
|
const char *schemaname;
|
|
|
|
schemaname = get_namespace_name(procform->pronamespace);
|
|
appendStringInfo(buf, "%s.", quote_identifier(schemaname));
|
|
}
|
|
|
|
/* Always print the function name */
|
|
proname = NameStr(procform->proname);
|
|
appendStringInfoString(buf, quote_identifier(proname));
|
|
|
|
ReleaseSysCache(proctup);
|
|
}
|
|
|
|
/*
|
|
* Appends a sort or group clause.
|
|
*
|
|
* Like get_rule_sortgroupclause(), returns the expression tree, so caller
|
|
* need not find it again.
|
|
*/
|
|
static Node *
|
|
deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
|
|
deparse_expr_cxt *context)
|
|
{
|
|
StringInfo buf = context->buf;
|
|
TargetEntry *tle;
|
|
Expr *expr;
|
|
|
|
tle = get_sortgroupref_tle(ref, tlist);
|
|
expr = tle->expr;
|
|
|
|
if (force_colno)
|
|
{
|
|
/* Use column-number form when requested by caller. */
|
|
Assert(!tle->resjunk);
|
|
appendStringInfo(buf, "%d", tle->resno);
|
|
}
|
|
else if (expr && IsA(expr, Const))
|
|
{
|
|
/*
|
|
* Force a typecast here so that we don't emit something like "GROUP
|
|
* BY 2", which will be misconstrued as a column position rather than
|
|
* a constant.
|
|
*/
|
|
deparseConst((Const *) expr, context, 1);
|
|
}
|
|
else if (!expr || IsA(expr, Var))
|
|
deparseExpr(expr, context);
|
|
else
|
|
{
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(expr, context);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
return (Node *) expr;
|
|
}
|
|
|
|
|
|
/*
|
|
* Returns true if given Var is deparsed as a subquery output column, in
|
|
* which case, *relno and *colno are set to the IDs for the relation and
|
|
* column alias to the Var provided by the subquery.
|
|
*/
|
|
static bool
|
|
is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
|
|
{
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
RelOptInfo *outerrel = fpinfo->outerrel;
|
|
RelOptInfo *innerrel = fpinfo->innerrel;
|
|
|
|
/* Should only be called in these cases. */
|
|
Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
|
|
|
|
/*
|
|
* If the given relation isn't a join relation, it doesn't have any lower
|
|
* subqueries, so the Var isn't a subquery output column.
|
|
*/
|
|
if (!IS_JOIN_REL(foreignrel))
|
|
return false;
|
|
|
|
/*
|
|
* If the Var doesn't belong to any lower subqueries, it isn't a subquery
|
|
* output column.
|
|
*/
|
|
if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
|
|
return false;
|
|
|
|
if (bms_is_member(node->varno, outerrel->relids))
|
|
{
|
|
/*
|
|
* If outer relation is deparsed as a subquery, the Var is an output
|
|
* column of the subquery; get the IDs for the relation/column alias.
|
|
*/
|
|
if (fpinfo->make_outerrel_subquery)
|
|
{
|
|
get_relation_column_alias_ids(node, outerrel, relno, colno);
|
|
return true;
|
|
}
|
|
|
|
/* Otherwise, recurse into the outer relation. */
|
|
return is_subquery_var(node, outerrel, relno, colno);
|
|
}
|
|
else
|
|
{
|
|
Assert(bms_is_member(node->varno, innerrel->relids));
|
|
|
|
/*
|
|
* If inner relation is deparsed as a subquery, the Var is an output
|
|
* column of the subquery; get the IDs for the relation/column alias.
|
|
*/
|
|
if (fpinfo->make_innerrel_subquery)
|
|
{
|
|
get_relation_column_alias_ids(node, innerrel, relno, colno);
|
|
return true;
|
|
}
|
|
|
|
/* Otherwise, recurse into the inner relation. */
|
|
return is_subquery_var(node, innerrel, relno, colno);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the IDs for the relation and column alias to given Var belonging to
|
|
* given relation, which are returned into *relno and *colno.
|
|
*/
|
|
static void
|
|
get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
|
|
int *relno, int *colno)
|
|
{
|
|
PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
|
|
int i;
|
|
ListCell *lc;
|
|
|
|
/* Get the relation alias ID */
|
|
*relno = fpinfo->relation_index;
|
|
|
|
/* Get the column alias ID */
|
|
i = 1;
|
|
foreach(lc, foreignrel->reltarget->exprs)
|
|
{
|
|
if (equal(lfirst(lc), (Node *) node))
|
|
{
|
|
*colno = i;
|
|
return;
|
|
}
|
|
i++;
|
|
}
|
|
|
|
/* Shouldn't get here */
|
|
elog(ERROR, "unexpected expression in subquery output");
|
|
}
|