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postgresql/src/backend/commands/explain.c

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/*-------------------------------------------------------------------------
*
* explain.c
* Explain query execution plans
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.164 2007/05/25 17:54:24 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xact.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_type.h"
#include "commands/explain.h"
#include "commands/prepare.h"
#include "commands/trigger.h"
#include "executor/instrument.h"
#include "nodes/print.h"
#include "optimizer/clauses.h"
#include "optimizer/planner.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/tuplesort.h"
/* Hook for plugins to get control in ExplainOneQuery() */
ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
/* Hook for plugins to get control in explain_get_index_name() */
explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
typedef struct ExplainState
{
/* options */
bool printNodes; /* do nodeToString() too */
bool printAnalyze; /* print actual times */
/* other states */
PlannedStmt *pstmt; /* top of plan */
List *rtable; /* range table */
} ExplainState;
static void ExplainOneQuery(Query *query, ExplainStmt *stmt,
const char *queryString,
ParamListInfo params, TupOutputState *tstate);
static double elapsed_time(instr_time *starttime);
static void explain_outNode(StringInfo str,
Plan *plan, PlanState *planstate,
Plan *outer_plan,
int indent, ExplainState *es);
static void show_scan_qual(List *qual, const char *qlabel,
int scanrelid, Plan *outer_plan, Plan *inner_plan,
StringInfo str, int indent, ExplainState *es);
static void show_upper_qual(List *qual, const char *qlabel, Plan *plan,
StringInfo str, int indent, ExplainState *es);
static void show_sort_keys(Plan *sortplan, int nkeys, AttrNumber *keycols,
const char *qlabel,
StringInfo str, int indent, ExplainState *es);
static void show_sort_info(SortState *sortstate,
StringInfo str, int indent, ExplainState *es);
static const char *explain_get_index_name(Oid indexId);
/*
* ExplainQuery -
* execute an EXPLAIN command
*/
void
ExplainQuery(ExplainStmt *stmt, const char *queryString,
ParamListInfo params, DestReceiver *dest)
{
Oid *param_types;
int num_params;
TupOutputState *tstate;
List *rewritten;
ListCell *l;
/* Convert parameter type data to the form parser wants */
getParamListTypes(params, &param_types, &num_params);
/*
* Run parse analysis and rewrite. Note this also acquires sufficient
* locks on the source table(s).
*
* Because the parser and planner tend to scribble on their input, we
* make a preliminary copy of the source querytree. This prevents
* problems in the case that the EXPLAIN is in a portal or plpgsql
* function and is executed repeatedly. (See also the same hack in
* DECLARE CURSOR and PREPARE.) XXX FIXME someday.
*/
rewritten = pg_analyze_and_rewrite((Node *) copyObject(stmt->query),
queryString, param_types, num_params);
/* prepare for projection of tuples */
tstate = begin_tup_output_tupdesc(dest, ExplainResultDesc(stmt));
if (rewritten == NIL)
{
/* In the case of an INSTEAD NOTHING, tell at least that */
do_text_output_oneline(tstate, "Query rewrites to nothing");
}
else
{
/* Explain every plan */
foreach(l, rewritten)
{
ExplainOneQuery((Query *) lfirst(l), stmt,
queryString, params, tstate);
/* put a blank line between plans */
if (lnext(l) != NULL)
do_text_output_oneline(tstate, "");
}
}
end_tup_output(tstate);
}
/*
* ExplainResultDesc -
* construct the result tupledesc for an EXPLAIN
*/
TupleDesc
ExplainResultDesc(ExplainStmt *stmt)
{
TupleDesc tupdesc;
/* need a tuple descriptor representing a single TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "QUERY PLAN",
TEXTOID, -1, 0);
return tupdesc;
}
/*
* ExplainOneQuery -
* print out the execution plan for one Query
*/
static void
ExplainOneQuery(Query *query, ExplainStmt *stmt, const char *queryString,
ParamListInfo params, TupOutputState *tstate)
{
/* planner will not cope with utility statements */
if (query->commandType == CMD_UTILITY)
{
ExplainOneUtility(query->utilityStmt, stmt,
queryString, params, tstate);
return;
}
/* if an advisor plugin is present, let it manage things */
if (ExplainOneQuery_hook)
(*ExplainOneQuery_hook) (query, stmt, queryString, params, tstate);
else
{
PlannedStmt *plan;
/* plan the query */
plan = planner(query, 0, params);
/* run it (if needed) and produce output */
ExplainOnePlan(plan, params, stmt, tstate);
}
}
/*
* ExplainOneUtility -
* print out the execution plan for one utility statement
* (In general, utility statements don't have plans, but there are some
* we treat as special cases)
*
* This is exported because it's called back from prepare.c in the
* EXPLAIN EXECUTE case
*/
void
ExplainOneUtility(Node *utilityStmt, ExplainStmt *stmt,
const char *queryString, ParamListInfo params,
TupOutputState *tstate)
{
if (utilityStmt == NULL)
return;
if (IsA(utilityStmt, ExecuteStmt))
ExplainExecuteQuery((ExecuteStmt *) utilityStmt, stmt,
queryString, params, tstate);
else if (IsA(utilityStmt, NotifyStmt))
do_text_output_oneline(tstate, "NOTIFY");
else
do_text_output_oneline(tstate,
"Utility statements have no plan structure");
}
/*
* ExplainOnePlan -
* given a planned query, execute it if needed, and then print
* EXPLAIN output
*
* Since we ignore any DeclareCursorStmt that might be attached to the query,
* if you say EXPLAIN ANALYZE DECLARE CURSOR then we'll actually run the
* query. This is different from pre-8.3 behavior but seems more useful than
* not running the query. No cursor will be created, however.
*
* This is exported because it's called back from prepare.c in the
* EXPLAIN EXECUTE case, and because an index advisor plugin would need
* to call it.
*/
void
ExplainOnePlan(PlannedStmt *plannedstmt, ParamListInfo params,
ExplainStmt *stmt, TupOutputState *tstate)
{
QueryDesc *queryDesc;
instr_time starttime;
double totaltime = 0;
ExplainState *es;
StringInfoData buf;
int eflags;
/*
* Update snapshot command ID to ensure this query sees results of any
* previously executed queries. (It's a bit cheesy to modify
* ActiveSnapshot without making a copy, but for the limited ways in which
* EXPLAIN can be invoked, I think it's OK, because the active snapshot
* shouldn't be shared with anything else anyway.)
*/
ActiveSnapshot->curcid = GetCurrentCommandId();
/* Create a QueryDesc requesting no output */
queryDesc = CreateQueryDesc(plannedstmt,
ActiveSnapshot, InvalidSnapshot,
None_Receiver, params,
stmt->analyze);
INSTR_TIME_SET_CURRENT(starttime);
/* If analyzing, we need to cope with queued triggers */
if (stmt->analyze)
AfterTriggerBeginQuery();
/* Select execution options */
if (stmt->analyze)
eflags = 0; /* default run-to-completion flags */
else
eflags = EXEC_FLAG_EXPLAIN_ONLY;
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, eflags);
/* Execute the plan for statistics if asked for */
if (stmt->analyze)
{
/* run the plan */
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
/* We can't clean up 'till we're done printing the stats... */
totaltime += elapsed_time(&starttime);
}
es = (ExplainState *) palloc0(sizeof(ExplainState));
es->printNodes = stmt->verbose;
es->printAnalyze = stmt->analyze;
es->pstmt = queryDesc->plannedstmt;
es->rtable = queryDesc->plannedstmt->rtable;
if (es->printNodes)
{
char *s;
char *f;
s = nodeToString(queryDesc->plannedstmt->planTree);
if (s)
{
if (Explain_pretty_print)
f = pretty_format_node_dump(s);
else
f = format_node_dump(s);
pfree(s);
do_text_output_multiline(tstate, f);
pfree(f);
do_text_output_oneline(tstate, ""); /* separator line */
}
}
initStringInfo(&buf);
explain_outNode(&buf,
queryDesc->plannedstmt->planTree, queryDesc->planstate,
NULL, 0, es);
/*
* If we ran the command, run any AFTER triggers it queued. (Note this
* will not include DEFERRED triggers; since those don't run until end of
* transaction, we can't measure them.) Include into total runtime.
*/
if (stmt->analyze)
{
INSTR_TIME_SET_CURRENT(starttime);
AfterTriggerEndQuery(queryDesc->estate);
totaltime += elapsed_time(&starttime);
}
/* Print info about runtime of triggers */
if (es->printAnalyze)
{
ResultRelInfo *rInfo;
int numrels = queryDesc->estate->es_num_result_relations;
int nr;
rInfo = queryDesc->estate->es_result_relations;
for (nr = 0; nr < numrels; rInfo++, nr++)
{
int nt;
if (!rInfo->ri_TrigDesc || !rInfo->ri_TrigInstrument)
continue;
for (nt = 0; nt < rInfo->ri_TrigDesc->numtriggers; nt++)
{
Trigger *trig = rInfo->ri_TrigDesc->triggers + nt;
Instrumentation *instr = rInfo->ri_TrigInstrument + nt;
char *conname;
/* Must clean up instrumentation state */
InstrEndLoop(instr);
/*
* We ignore triggers that were never invoked; they likely
* aren't relevant to the current query type.
*/
if (instr->ntuples == 0)
continue;
if (OidIsValid(trig->tgconstraint) &&
(conname = get_constraint_name(trig->tgconstraint)) != NULL)
{
appendStringInfo(&buf, "Trigger for constraint %s",
conname);
pfree(conname);
}
else
appendStringInfo(&buf, "Trigger %s", trig->tgname);
if (numrels > 1)
appendStringInfo(&buf, " on %s",
RelationGetRelationName(rInfo->ri_RelationDesc));
appendStringInfo(&buf, ": time=%.3f calls=%.0f\n",
1000.0 * instr->total,
instr->ntuples);
}
}
}
/*
* Close down the query and free resources. Include time for this in the
* total runtime (although it should be pretty minimal).
*/
INSTR_TIME_SET_CURRENT(starttime);
ExecutorEnd(queryDesc);
FreeQueryDesc(queryDesc);
/* We need a CCI just in case query expanded to multiple plans */
if (stmt->analyze)
CommandCounterIncrement();
totaltime += elapsed_time(&starttime);
if (stmt->analyze)
appendStringInfo(&buf, "Total runtime: %.3f ms\n",
1000.0 * totaltime);
do_text_output_multiline(tstate, buf.data);
pfree(buf.data);
pfree(es);
}
/* Compute elapsed time in seconds since given timestamp */
static double
elapsed_time(instr_time *starttime)
{
instr_time endtime;
INSTR_TIME_SET_CURRENT(endtime);
#ifndef WIN32
endtime.tv_sec -= starttime->tv_sec;
endtime.tv_usec -= starttime->tv_usec;
while (endtime.tv_usec < 0)
{
endtime.tv_usec += 1000000;
endtime.tv_sec--;
}
#else /* WIN32 */
endtime.QuadPart -= starttime->QuadPart;
#endif
return INSTR_TIME_GET_DOUBLE(endtime);
}
/*
* explain_outNode -
* converts a Plan node into ascii string and appends it to 'str'
*
* planstate points to the executor state node corresponding to the plan node.
* We need this to get at the instrumentation data (if any) as well as the
* list of subplans.
*
* outer_plan, if not null, references another plan node that is the outer
* side of a join with the current node. This is only interesting for
* deciphering runtime keys of an inner indexscan.
*/
static void
explain_outNode(StringInfo str,
Plan *plan, PlanState *planstate,
Plan *outer_plan,
int indent, ExplainState *es)
{
char *pname;
int i;
if (plan == NULL)
{
appendStringInfoChar(str, '\n');
return;
}
switch (nodeTag(plan))
{
case T_Result:
pname = "Result";
break;
case T_Append:
pname = "Append";
break;
case T_BitmapAnd:
pname = "BitmapAnd";
break;
case T_BitmapOr:
pname = "BitmapOr";
break;
case T_NestLoop:
switch (((NestLoop *) plan)->join.jointype)
{
case JOIN_INNER:
pname = "Nested Loop";
break;
case JOIN_LEFT:
pname = "Nested Loop Left Join";
break;
case JOIN_FULL:
pname = "Nested Loop Full Join";
break;
case JOIN_RIGHT:
pname = "Nested Loop Right Join";
break;
case JOIN_IN:
pname = "Nested Loop IN Join";
break;
default:
pname = "Nested Loop ??? Join";
break;
}
break;
case T_MergeJoin:
switch (((MergeJoin *) plan)->join.jointype)
{
case JOIN_INNER:
pname = "Merge Join";
break;
case JOIN_LEFT:
pname = "Merge Left Join";
break;
case JOIN_FULL:
pname = "Merge Full Join";
break;
case JOIN_RIGHT:
pname = "Merge Right Join";
break;
case JOIN_IN:
pname = "Merge IN Join";
break;
default:
pname = "Merge ??? Join";
break;
}
break;
case T_HashJoin:
switch (((HashJoin *) plan)->join.jointype)
{
case JOIN_INNER:
pname = "Hash Join";
break;
case JOIN_LEFT:
pname = "Hash Left Join";
break;
case JOIN_FULL:
pname = "Hash Full Join";
break;
case JOIN_RIGHT:
pname = "Hash Right Join";
break;
case JOIN_IN:
pname = "Hash IN Join";
break;
default:
pname = "Hash ??? Join";
break;
}
break;
case T_SeqScan:
pname = "Seq Scan";
break;
case T_IndexScan:
pname = "Index Scan";
break;
case T_BitmapIndexScan:
pname = "Bitmap Index Scan";
break;
case T_BitmapHeapScan:
pname = "Bitmap Heap Scan";
break;
case T_TidScan:
pname = "Tid Scan";
break;
case T_SubqueryScan:
pname = "Subquery Scan";
break;
case T_FunctionScan:
pname = "Function Scan";
break;
case T_ValuesScan:
pname = "Values Scan";
break;
case T_Material:
pname = "Materialize";
break;
case T_Sort:
pname = "Sort";
break;
case T_Group:
pname = "Group";
break;
case T_Agg:
switch (((Agg *) plan)->aggstrategy)
{
case AGG_PLAIN:
pname = "Aggregate";
break;
case AGG_SORTED:
pname = "GroupAggregate";
break;
case AGG_HASHED:
pname = "HashAggregate";
break;
default:
pname = "Aggregate ???";
break;
}
break;
case T_Unique:
pname = "Unique";
break;
case T_SetOp:
switch (((SetOp *) plan)->cmd)
{
case SETOPCMD_INTERSECT:
pname = "SetOp Intersect";
break;
case SETOPCMD_INTERSECT_ALL:
pname = "SetOp Intersect All";
break;
case SETOPCMD_EXCEPT:
pname = "SetOp Except";
break;
case SETOPCMD_EXCEPT_ALL:
pname = "SetOp Except All";
break;
default:
pname = "SetOp ???";
break;
}
break;
case T_Limit:
pname = "Limit";
break;
case T_Hash:
pname = "Hash";
break;
default:
pname = "???";
break;
}
appendStringInfoString(str, pname);
switch (nodeTag(plan))
{
case T_IndexScan:
if (ScanDirectionIsBackward(((IndexScan *) plan)->indexorderdir))
appendStringInfoString(str, " Backward");
appendStringInfo(str, " using %s",
explain_get_index_name(((IndexScan *) plan)->indexid));
/* FALL THRU */
case T_SeqScan:
case T_BitmapHeapScan:
case T_TidScan:
if (((Scan *) plan)->scanrelid > 0)
{
RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
es->rtable);
char *relname;
/* Assume it's on a real relation */
Assert(rte->rtekind == RTE_RELATION);
/* We only show the rel name, not schema name */
relname = get_rel_name(rte->relid);
appendStringInfo(str, " on %s",
quote_identifier(relname));
if (strcmp(rte->eref->aliasname, relname) != 0)
appendStringInfo(str, " %s",
quote_identifier(rte->eref->aliasname));
}
break;
case T_BitmapIndexScan:
appendStringInfo(str, " on %s",
explain_get_index_name(((BitmapIndexScan *) plan)->indexid));
break;
case T_SubqueryScan:
if (((Scan *) plan)->scanrelid > 0)
{
RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
es->rtable);
appendStringInfo(str, " %s",
quote_identifier(rte->eref->aliasname));
}
break;
case T_FunctionScan:
if (((Scan *) plan)->scanrelid > 0)
{
RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
es->rtable);
Node *funcexpr;
char *proname;
/* Assert it's on a RangeFunction */
Assert(rte->rtekind == RTE_FUNCTION);
/*
* If the expression is still a function call, we can get the
* real name of the function. Otherwise, punt (this can
* happen if the optimizer simplified away the function call,
* for example).
*/
funcexpr = ((FunctionScan *) plan)->funcexpr;
if (funcexpr && IsA(funcexpr, FuncExpr))
{
Oid funcid = ((FuncExpr *) funcexpr)->funcid;
/* We only show the func name, not schema name */
proname = get_func_name(funcid);
}
else
proname = rte->eref->aliasname;
appendStringInfo(str, " on %s",
quote_identifier(proname));
if (strcmp(rte->eref->aliasname, proname) != 0)
appendStringInfo(str, " %s",
quote_identifier(rte->eref->aliasname));
}
break;
case T_ValuesScan:
if (((Scan *) plan)->scanrelid > 0)
{
RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
es->rtable);
char *valsname;
/* Assert it's on a values rte */
Assert(rte->rtekind == RTE_VALUES);
valsname = rte->eref->aliasname;
appendStringInfo(str, " on %s",
quote_identifier(valsname));
}
break;
default:
break;
}
appendStringInfo(str, " (cost=%.2f..%.2f rows=%.0f width=%d)",
plan->startup_cost, plan->total_cost,
plan->plan_rows, plan->plan_width);
/*
* We have to forcibly clean up the instrumentation state because we
* haven't done ExecutorEnd yet. This is pretty grotty ...
*/
if (planstate->instrument)
InstrEndLoop(planstate->instrument);
if (planstate->instrument && planstate->instrument->nloops > 0)
{
double nloops = planstate->instrument->nloops;
appendStringInfo(str, " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
1000.0 * planstate->instrument->startup / nloops,
1000.0 * planstate->instrument->total / nloops,
planstate->instrument->ntuples / nloops,
planstate->instrument->nloops);
}
else if (es->printAnalyze)
appendStringInfo(str, " (never executed)");
appendStringInfoChar(str, '\n');
/* quals, sort keys, etc */
switch (nodeTag(plan))
{
case T_IndexScan:
show_scan_qual(((IndexScan *) plan)->indexqualorig,
"Index Cond",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
show_scan_qual(plan->qual,
"Filter",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
break;
case T_BitmapIndexScan:
show_scan_qual(((BitmapIndexScan *) plan)->indexqualorig,
"Index Cond",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
break;
case T_BitmapHeapScan:
/* XXX do we want to show this in production? */
show_scan_qual(((BitmapHeapScan *) plan)->bitmapqualorig,
"Recheck Cond",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
/* FALL THRU */
case T_SeqScan:
case T_FunctionScan:
case T_ValuesScan:
show_scan_qual(plan->qual,
"Filter",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
break;
case T_SubqueryScan:
show_scan_qual(plan->qual,
"Filter",
((Scan *) plan)->scanrelid,
outer_plan,
((SubqueryScan *) plan)->subplan,
str, indent, es);
break;
case T_TidScan:
{
/*
* The tidquals list has OR semantics, so be sure to show it
* as an OR condition.
*/
List *tidquals = ((TidScan *) plan)->tidquals;
if (list_length(tidquals) > 1)
tidquals = list_make1(make_orclause(tidquals));
show_scan_qual(tidquals,
"TID Cond",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
show_scan_qual(plan->qual,
"Filter",
((Scan *) plan)->scanrelid,
outer_plan, NULL,
str, indent, es);
}
break;
case T_NestLoop:
show_upper_qual(((NestLoop *) plan)->join.joinqual,
"Join Filter", plan,
str, indent, es);
show_upper_qual(plan->qual,
"Filter", plan,
str, indent, es);
break;
case T_MergeJoin:
show_upper_qual(((MergeJoin *) plan)->mergeclauses,
"Merge Cond", plan,
str, indent, es);
show_upper_qual(((MergeJoin *) plan)->join.joinqual,
"Join Filter", plan,
str, indent, es);
show_upper_qual(plan->qual,
"Filter", plan,
str, indent, es);
break;
case T_HashJoin:
show_upper_qual(((HashJoin *) plan)->hashclauses,
"Hash Cond", plan,
str, indent, es);
show_upper_qual(((HashJoin *) plan)->join.joinqual,
"Join Filter", plan,
str, indent, es);
show_upper_qual(plan->qual,
"Filter", plan,
str, indent, es);
break;
case T_Agg:
case T_Group:
show_upper_qual(plan->qual,
"Filter", plan,
str, indent, es);
break;
case T_Sort:
show_sort_keys(plan,
((Sort *) plan)->numCols,
((Sort *) plan)->sortColIdx,
"Sort Key",
str, indent, es);
show_sort_info((SortState *) planstate,
str, indent, es);
break;
case T_Result:
show_upper_qual((List *) ((Result *) plan)->resconstantqual,
"One-Time Filter", plan,
str, indent, es);
show_upper_qual(plan->qual,
"Filter", plan,
str, indent, es);
break;
default:
break;
}
/* initPlan-s */
if (plan->initPlan)
{
ListCell *lst;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " InitPlan\n");
foreach(lst, planstate->initPlan)
{
SubPlanState *sps = (SubPlanState *) lfirst(lst);
SubPlan *sp = (SubPlan *) sps->xprstate.expr;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str,
exec_subplan_get_plan(es->pstmt, sp),
sps->planstate,
NULL,
indent + 4, es);
}
}
/* lefttree */
if (outerPlan(plan))
{
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
/*
* Ordinarily we don't pass down our own outer_plan value to our child
* nodes, but in bitmap scan trees we must, since the bottom
* BitmapIndexScan nodes may have outer references.
*/
explain_outNode(str, outerPlan(plan),
outerPlanState(planstate),
IsA(plan, BitmapHeapScan) ? outer_plan : NULL,
indent + 3, es);
}
/* righttree */
if (innerPlan(plan))
{
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str, innerPlan(plan),
innerPlanState(planstate),
outerPlan(plan),
indent + 3, es);
}
if (IsA(plan, Append))
{
Append *appendplan = (Append *) plan;
AppendState *appendstate = (AppendState *) planstate;
ListCell *lst;
int j;
j = 0;
foreach(lst, appendplan->appendplans)
{
Plan *subnode = (Plan *) lfirst(lst);
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
/*
* Ordinarily we don't pass down our own outer_plan value to our
* child nodes, but in an Append we must, since we might be
* looking at an appendrel indexscan with outer references from
* the member scans.
*/
explain_outNode(str, subnode,
appendstate->appendplans[j],
outer_plan,
indent + 3, es);
j++;
}
}
if (IsA(plan, BitmapAnd))
{
BitmapAnd *bitmapandplan = (BitmapAnd *) plan;
BitmapAndState *bitmapandstate = (BitmapAndState *) planstate;
ListCell *lst;
int j;
j = 0;
foreach(lst, bitmapandplan->bitmapplans)
{
Plan *subnode = (Plan *) lfirst(lst);
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str, subnode,
bitmapandstate->bitmapplans[j],
outer_plan, /* pass down same outer plan */
indent + 3, es);
j++;
}
}
if (IsA(plan, BitmapOr))
{
BitmapOr *bitmaporplan = (BitmapOr *) plan;
BitmapOrState *bitmaporstate = (BitmapOrState *) planstate;
ListCell *lst;
int j;
j = 0;
foreach(lst, bitmaporplan->bitmapplans)
{
Plan *subnode = (Plan *) lfirst(lst);
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str, subnode,
bitmaporstate->bitmapplans[j],
outer_plan, /* pass down same outer plan */
indent + 3, es);
j++;
}
}
if (IsA(plan, SubqueryScan))
{
SubqueryScan *subqueryscan = (SubqueryScan *) plan;
SubqueryScanState *subquerystate = (SubqueryScanState *) planstate;
Plan *subnode = subqueryscan->subplan;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str, subnode,
subquerystate->subplan,
NULL,
indent + 3, es);
}
/* subPlan-s */
if (planstate->subPlan)
{
ListCell *lst;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " SubPlan\n");
foreach(lst, planstate->subPlan)
{
SubPlanState *sps = (SubPlanState *) lfirst(lst);
SubPlan *sp = (SubPlan *) sps->xprstate.expr;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " -> ");
explain_outNode(str,
exec_subplan_get_plan(es->pstmt, sp),
sps->planstate,
NULL,
indent + 4, es);
}
}
}
/*
* Show a qualifier expression for a scan plan node
*
* Note: outer_plan is the referent for any OUTER vars in the scan qual;
* this would be the outer side of a nestloop plan. inner_plan should be
* NULL except for a SubqueryScan plan node, where it should be the subplan.
*/
static void
show_scan_qual(List *qual, const char *qlabel,
int scanrelid, Plan *outer_plan, Plan *inner_plan,
StringInfo str, int indent, ExplainState *es)
{
List *context;
bool useprefix;
Node *node;
char *exprstr;
int i;
/* No work if empty qual */
if (qual == NIL)
return;
/* Convert AND list to explicit AND */
node = (Node *) make_ands_explicit(qual);
/* Set up deparsing context */
context = deparse_context_for_plan((Node *) outer_plan,
(Node *) inner_plan,
es->rtable);
useprefix = (outer_plan != NULL || inner_plan != NULL);
/* Deparse the expression */
exprstr = deparse_expression(node, context, useprefix, false);
/* And add to str */
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " %s: %s\n", qlabel, exprstr);
}
/*
* Show a qualifier expression for an upper-level plan node
*/
static void
show_upper_qual(List *qual, const char *qlabel, Plan *plan,
StringInfo str, int indent, ExplainState *es)
{
List *context;
bool useprefix;
Node *node;
char *exprstr;
int i;
/* No work if empty qual */
if (qual == NIL)
return;
/* Set up deparsing context */
context = deparse_context_for_plan((Node *) outerPlan(plan),
(Node *) innerPlan(plan),
es->rtable);
useprefix = list_length(es->rtable) > 1;
/* Deparse the expression */
node = (Node *) make_ands_explicit(qual);
exprstr = deparse_expression(node, context, useprefix, false);
/* And add to str */
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " %s: %s\n", qlabel, exprstr);
}
/*
* Show the sort keys for a Sort node.
*/
static void
show_sort_keys(Plan *sortplan, int nkeys, AttrNumber *keycols,
const char *qlabel,
StringInfo str, int indent, ExplainState *es)
{
List *context;
bool useprefix;
int keyno;
char *exprstr;
int i;
if (nkeys <= 0)
return;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " %s: ", qlabel);
/* Set up deparsing context */
context = deparse_context_for_plan((Node *) outerPlan(sortplan),
NULL, /* Sort has no innerPlan */
es->rtable);
useprefix = list_length(es->rtable) > 1;
for (keyno = 0; keyno < nkeys; keyno++)
{
/* find key expression in tlist */
AttrNumber keyresno = keycols[keyno];
TargetEntry *target = get_tle_by_resno(sortplan->targetlist, keyresno);
if (!target)
elog(ERROR, "no tlist entry for key %d", keyresno);
/* Deparse the expression, showing any top-level cast */
exprstr = deparse_expression((Node *) target->expr, context,
useprefix, true);
/* And add to str */
if (keyno > 0)
appendStringInfo(str, ", ");
appendStringInfoString(str, exprstr);
}
appendStringInfo(str, "\n");
}
/*
* If it's EXPLAIN ANALYZE, show tuplesort explain info for a sort node
*/
static void
show_sort_info(SortState *sortstate,
StringInfo str, int indent, ExplainState *es)
{
Assert(IsA(sortstate, SortState));
if (es->printAnalyze && sortstate->sort_Done &&
sortstate->tuplesortstate != NULL)
{
char *sortinfo;
int i;
sortinfo = tuplesort_explain((Tuplesortstate *) sortstate->tuplesortstate);
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " %s\n", sortinfo);
pfree(sortinfo);
}
}
/*
* Fetch the name of an index in an EXPLAIN
*
* We allow plugins to get control here so that plans involving hypothetical
* indexes can be explained.
*/
static const char *
explain_get_index_name(Oid indexId)
{
const char *result;
if (explain_get_index_name_hook)
result = (*explain_get_index_name_hook) (indexId);
else
result = NULL;
if (result == NULL)
{
/* default behavior: look in the catalogs and quote it */
result = get_rel_name(indexId);
if (result == NULL)
elog(ERROR, "cache lookup failed for index %u", indexId);
result = quote_identifier(result);
}
return result;
}
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