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Allow OLD and NEW in multi-row VALUES within rules. 

Now that we have LATERAL, it's fairly painless to allow this case, which
was left as a TODO in the original multi-row VALUES implementation.
This commit is contained in:
Tom Lane 2012-08-19 14:12:16 -04:00
parent c246eb5aaf
commit 092d7ded29
8 changed files with 164 additions and 47 deletions
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4
src/backend/optimizer/path/allpaths.c
View File

@ -1221,9 +1221,7 @@ set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
/*
* If it's a LATERAL RTE, it might contain some Vars of the current query
* level, requiring it to be treated as parameterized. (NB: even though
* the parser never marks VALUES RTEs as LATERAL, they could be so marked
* by now, as a result of subquery pullup.)
* level, requiring it to be treated as parameterized.
*/
if (rte->lateral)
{

46
src/backend/parser/analyze.c
View File

@ -587,6 +587,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
List *exprsLists = NIL;
List *collations = NIL;
int sublist_length = -1;
bool lateral = false;
int i;
Assert(selectStmt->intoClause == NULL);
@ -647,25 +648,20 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
collations = lappend_oid(collations, InvalidOid);
/*
* Another thing we can't currently support is NEW/OLD references in
* rules --- seems we'd need something like SQL99's LATERAL construct
* to ensure that the values would be available while evaluating the
* VALUES RTE. This is a shame. FIXME
* Ordinarily there can't be any current-level Vars in the expression
* lists, because the namespace was empty ... but if we're inside
* CREATE RULE, then NEW/OLD references might appear. In that case we
* have to mark the VALUES RTE as LATERAL.
*/
if (list_length(pstate->p_rtable) != 1 &&
contain_vars_of_level((Node *) exprsLists, 0))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain OLD or NEW references"),
errhint("Use SELECT ... UNION ALL ... instead."),
parser_errposition(pstate,
locate_var_of_level((Node *) exprsLists, 0))));
lateral = true;
/*
* Generate the VALUES RTE
*/
rte = addRangeTableEntryForValues(pstate, exprsLists, collations,
NULL, true);
NULL, lateral, true);
rtr = makeNode(RangeTblRef);
/* assume new rte is at end */
rtr->rtindex = list_length(pstate->p_rtable);
@ -1032,6 +1028,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
List *collations;
List **colexprs = NULL;
int sublist_length = -1;
bool lateral = false;
RangeTblEntry *rte;
int rtindex;
ListCell *lc;
@ -1176,11 +1173,21 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
list_free(colexprs[i]);
}
/*
* Ordinarily there can't be any current-level Vars in the expression
* lists, because the namespace was empty ... but if we're inside CREATE
* RULE, then NEW/OLD references might appear. In that case we have to
* mark the VALUES RTE as LATERAL.
*/
if (pstate->p_rtable != NIL &&
contain_vars_of_level((Node *) exprsLists, 0))
lateral = true;
/*
* Generate the VALUES RTE
*/
rte = addRangeTableEntryForValues(pstate, exprsLists, collations,
NULL, true);
NULL, lateral, true);
addRTEtoQuery(pstate, rte, true, true, true);
/* assume new rte is at end */
@ -1214,21 +1221,6 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to VALUES")));
/*
* Another thing we can't currently support is NEW/OLD references in rules
* --- seems we'd need something like SQL99's LATERAL construct to ensure
* that the values would be available while evaluating the VALUES RTE.
* This is a shame. FIXME
*/
if (list_length(pstate->p_rtable) != 1 &&
contain_vars_of_level((Node *) exprsLists, 0))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain OLD or NEW references"),
errhint("Use SELECT ... UNION ALL ... instead."),
parser_errposition(pstate,
locate_var_of_level((Node *) exprsLists, 0))));
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);

3
src/backend/parser/parse_relation.c
View File

@ -1313,6 +1313,7 @@ addRangeTableEntryForValues(ParseState *pstate,
List *exprs,
List *collations,
Alias *alias,
bool lateral,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
@ -1355,7 +1356,7 @@ addRangeTableEntryForValues(ParseState *pstate,
*
* Subqueries are never checked for access rights.
*/
rte->lateral = false;
rte->lateral = lateral;
rte->inh = false; /* never true for values RTEs */
rte->inFromCl = inFromCl;

57
src/backend/utils/adt/ruleutils.c
View File

@ -2919,11 +2919,48 @@ get_select_query_def(Query *query, deparse_context *context,
context->windowTList = save_windowtlist;
}
/*
* Detect whether query looks like SELECT ... FROM VALUES();
* if so, return the VALUES RTE. Otherwise return NULL.
*/
static RangeTblEntry *
get_simple_values_rte(Query *query)
{
RangeTblEntry *result = NULL;
ListCell *lc;
/*
* We want to return TRUE even if the Query also contains OLD or NEW rule
* RTEs. So the idea is to scan the rtable and see if there is only one
* inFromCl RTE that is a VALUES RTE. We don't look at the targetlist at
* all. This is okay because parser/analyze.c will never generate a
* "bare" VALUES RTE --- they only appear inside auto-generated
* sub-queries with very restricted structure.
*/
foreach(lc, query->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
if (rte->rtekind == RTE_VALUES && rte->inFromCl)
{
if (result)
return NULL; /* multiple VALUES (probably not possible) */
result = rte;
}
else if (rte->rtekind == RTE_RELATION && !rte->inFromCl)
continue; /* ignore rule entries */
else
return NULL; /* something else -> not simple VALUES */
}
return result;
}
static void
get_basic_select_query(Query *query, deparse_context *context,
TupleDesc resultDesc)
{
StringInfo buf = context->buf;
RangeTblEntry *values_rte;
char *sep;
ListCell *l;
@ -2936,23 +2973,13 @@ get_basic_select_query(Query *query, deparse_context *context,
/*
* If the query looks like SELECT * FROM (VALUES ...), then print just the
* VALUES part. This reverses what transformValuesClause() did at parse
* time. If the jointree contains just a single VALUES RTE, we assume
* this case applies (without looking at the targetlist...)
* time.
*/
if (list_length(query->jointree->fromlist) == 1)
values_rte = get_simple_values_rte(query);
if (values_rte)
{
RangeTblRef *rtr = (RangeTblRef *) linitial(query->jointree->fromlist);
if (IsA(rtr, RangeTblRef))
{
RangeTblEntry *rte = rt_fetch(rtr->rtindex, query->rtable);
if (rte->rtekind == RTE_VALUES)
{
get_values_def(rte->values_lists, context);
return;
}
}
get_values_def(values_rte->values_lists, context);
return;
}
/*

2
src/include/nodes/parsenodes.h
View File

@ -758,7 +758,7 @@ typedef struct RangeTblEntry
*/
Alias *alias; /* user-written alias clause, if any */
Alias *eref; /* expanded reference names */
bool lateral; /* subquery or function is marked LATERAL? */
bool lateral; /* subquery, function, or values is LATERAL? */
bool inh; /* inheritance requested? */
bool inFromCl; /* present in FROM clause? */
AclMode requiredPerms; /* bitmask of required access permissions */

1
src/include/parser/parse_relation.h
View File

@ -67,6 +67,7 @@ extern RangeTblEntry *addRangeTableEntryForValues(ParseState *pstate,
List *exprs,
List *collations,
Alias *alias,
bool lateral,
bool inFromCl);
extern RangeTblEntry *addRangeTableEntryForJoin(ParseState *pstate,
List *colnames,

78
src/test/regress/expected/rules.out
View File

@ -1593,3 +1593,81 @@ select pg_get_viewdef('shoe'::regclass,0) as prettier;
WHERE sh.slunit = un.un_name;
(1 row)
--
-- check multi-rule VALUES in rules
--
create table rules_src(f1 int, f2 int);
create table rules_log(f1 int, f2 int, tag text);
insert into rules_src values(1,2), (11,12);
create rule r1 as on update to rules_src do also
insert into rules_log values(old.*, 'old'), (new.*, 'new');
update rules_src set f2 = f2 + 1;
update rules_src set f2 = f2 * 10;
select * from rules_src;
f1 | f2
----+-----
1 | 30
11 | 130
(2 rows)
select * from rules_log;
f1 | f2 | tag
----+-----+-----
1 | 2 | old
1 | 3 | new
11 | 12 | old
11 | 13 | new
1 | 3 | old
1 | 30 | new
11 | 13 | old
11 | 130 | new
(8 rows)
create rule r2 as on update to rules_src do also
values(old.*, 'old'), (new.*, 'new');
update rules_src set f2 = f2 / 10;
column1 | column2 | column3
---------+---------+---------
1 | 30 | old
1 | 3 | new
11 | 130 | old
11 | 13 | new
(4 rows)
select * from rules_src;
f1 | f2
----+----
1 | 3
11 | 13
(2 rows)
select * from rules_log;
f1 | f2 | tag
----+-----+-----
1 | 2 | old
1 | 3 | new
11 | 12 | old
11 | 13 | new
1 | 3 | old
1 | 30 | new
11 | 13 | old
11 | 130 | new
1 | 30 | old
1 | 3 | new
11 | 130 | old
11 | 13 | new
(12 rows)
\d+ rules_src
Table "public.rules_src"
Column | Type | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------
f1 | integer | | plain | |
f2 | integer | | plain | |
Rules:
r1 AS
ON UPDATE TO rules_src DO INSERT INTO rules_log (f1, f2, tag) VALUES (old.f1,old.f2,'old'::text), (new.f1,new.f2,'new'::text)
r2 AS
ON UPDATE TO rules_src DO VALUES (old.f1,old.f2,'old'::text), (new.f1,new.f2,'new'::text)
Has OIDs: no

20
src/test/regress/sql/rules.sql
View File

@ -933,3 +933,23 @@ select * from only t1_2;
select pg_get_viewdef('shoe'::regclass) as unpretty;
select pg_get_viewdef('shoe'::regclass,true) as pretty;
select pg_get_viewdef('shoe'::regclass,0) as prettier;
--
-- check multi-rule VALUES in rules
--
create table rules_src(f1 int, f2 int);
create table rules_log(f1 int, f2 int, tag text);
insert into rules_src values(1,2), (11,12);
create rule r1 as on update to rules_src do also
insert into rules_log values(old.*, 'old'), (new.*, 'new');
update rules_src set f2 = f2 + 1;
update rules_src set f2 = f2 * 10;
select * from rules_src;
select * from rules_log;
create rule r2 as on update to rules_src do also
values(old.*, 'old'), (new.*, 'new');
update rules_src set f2 = f2 / 10;
select * from rules_src;
select * from rules_log;
\d+ rules_src