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Fix LATERAL references to join alias variables.

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I had thought this case worked already, but perhaps I didn't re-test it
after adding extract_lateral_references() ...
This commit is contained in:
Tom Lane 2012-08-31 17:44:01 -04:00
parent f789909b59
commit da3df99870
4 changed files with 78 additions and 19 deletions
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59
src/backend/optimizer/plan/planner.c
View File

@ -49,13 +49,15 @@ planner_hook_type planner_hook = NULL;
/* Expression kind codes for preprocess_expression */
#define EXPRKIND_QUAL 0
#define EXPRKIND_TARGET 1
#define EXPRKIND_RTFUNC 2
#define EXPRKIND_VALUES 3
#define EXPRKIND_LIMIT 4
#define EXPRKIND_APPINFO 5
#define EXPRKIND_PHV 6
#define EXPRKIND_QUAL 0
#define EXPRKIND_TARGET 1
#define EXPRKIND_RTFUNC 2
#define EXPRKIND_RTFUNC_LATERAL 3
#define EXPRKIND_VALUES 4
#define EXPRKIND_VALUES_LATERAL 5
#define EXPRKIND_LIMIT 6
#define EXPRKIND_APPINFO 7
#define EXPRKIND_PHV 8
static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind);
@ -438,18 +440,38 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
preprocess_expression(root, (Node *) root->append_rel_list,
EXPRKIND_APPINFO);
/* Also need to preprocess expressions for function and values RTEs */
/* Also need to preprocess expressions within RTEs */
foreach(l, parse->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
int kind;
if (rte->rtekind == RTE_FUNCTION)
rte->funcexpr = preprocess_expression(root, rte->funcexpr,
EXPRKIND_RTFUNC);
if (rte->rtekind == RTE_SUBQUERY)
{
/*
* We don't want to do all preprocessing yet on the subquery's
* expressions, since that will happen when we plan it. But if it
* contains any join aliases of our level, those have to get
* expanded now, because planning of the subquery won't do it.
* That's only possible if the subquery is LATERAL.
*/
if (rte->lateral && root->hasJoinRTEs)
rte->subquery = (Query *)
flatten_join_alias_vars(root, (Node *) rte->subquery);
}
else if (rte->rtekind == RTE_FUNCTION)
{
/* Preprocess the function expression fully */
kind = rte->lateral ? EXPRKIND_RTFUNC_LATERAL : EXPRKIND_RTFUNC;
rte->funcexpr = preprocess_expression(root, rte->funcexpr, kind);
}
else if (rte->rtekind == RTE_VALUES)
{
/* Preprocess the values lists fully */
kind = rte->lateral ? EXPRKIND_VALUES_LATERAL : EXPRKIND_VALUES;
rte->values_lists = (List *)
preprocess_expression(root, (Node *) rte->values_lists,
EXPRKIND_VALUES);
preprocess_expression(root, (Node *) rte->values_lists, kind);
}
}
/*
@ -593,12 +615,13 @@ preprocess_expression(PlannerInfo *root, Node *expr, int kind)
/*
* If the query has any join RTEs, replace join alias variables with
* base-relation variables. We must do this before sublink processing,
* else sublinks expanded out from join aliases wouldn't get processed. We
* can skip it in VALUES lists, however, since they can't contain any Vars
* at all.
* base-relation variables. We must do this before sublink processing,
* else sublinks expanded out from join aliases would not get processed.
* We can skip it in non-lateral RTE functions and VALUES lists, however,
* since they can't contain any Vars of the current query level.
*/
if (root->hasJoinRTEs && kind != EXPRKIND_VALUES)
if (root->hasJoinRTEs &&
!(kind == EXPRKIND_RTFUNC || kind == EXPRKIND_VALUES))
expr = flatten_join_alias_vars(root, expr);
/*

4
src/backend/optimizer/util/var.c
View File

@ -600,7 +600,9 @@ pull_var_clause_walker(Node *node, pull_var_clause_context *context)
* hasSubLinks = TRUE, so this is only relevant to un-flattened subqueries.
*
* NOTE: this is used on not-yet-planned expressions. We do not expect it
* to be applied directly to a Query node.
* to be applied directly to the whole Query, so if we see a Query to start
* with, we do want to increment sublevels_up (this occurs for LATERAL
* subqueries).
*/
Node *
flatten_join_alias_vars(PlannerInfo *root, Node *node)

26
src/test/regress/expected/join.out
View File

@ -3242,6 +3242,32 @@ select * from int8_tbl a,
4567890123456789 | -4567890123456789 | 4567890123456789 | -4567890123456789 |
(57 rows)
-- lateral reference to a join alias variable
select * from (select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1,
lateral (select x) ss2(y);
x | f1 | y
---+----+---
0 | 0 | 0
(1 row)
select * from (select f1 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1,
lateral (values(x)) ss2(y);
x | f1 | y
-------------+-------------+-------------
0 | 0 | 0
123456 | 123456 | 123456
-123456 | -123456 | -123456
2147483647 | 2147483647 | 2147483647
-2147483647 | -2147483647 | -2147483647
(5 rows)
select * from ((select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1) j,
lateral (select x) ss2(y);
x | f1 | y
---+----+---
0 | 0 | 0
(1 row)
-- lateral references requiring pullup
select * from (values(1)) x(lb),
lateral generate_series(lb,4) x4;

8
src/test/regress/sql/join.sql
View File

@ -901,6 +901,14 @@ select * from int8_tbl a,
int8_tbl x left join lateral (select a.q1 from int4_tbl y) ss(z)
on x.q2 = ss.z;
-- lateral reference to a join alias variable
select * from (select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1,
lateral (select x) ss2(y);
select * from (select f1 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1,
lateral (values(x)) ss2(y);
select * from ((select f1/2 as x from int4_tbl) ss1 join int4_tbl i4 on x = f1) j,
lateral (select x) ss2(y);
-- lateral references requiring pullup
select * from (values(1)) x(lb),
lateral generate_series(lb,4) x4;