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Repair planner failure when there are multiple IN clauses, each with

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a join in its subselect.  In this situation we *must* build a bushy
plan because there are no valid left-sided or right-sided join trees.
Accordingly, hoary sanity check needs an update.  Per report from
Alessandro Depase.
This commit is contained in:
Tom Lane 2003-12-17 17:07:48 +00:00
parent 9dddd242dd
commit 99e922a01d
2 changed files with 22 additions and 3 deletions
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4
src/backend/optimizer/path/allpaths.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.109 2003/11/29 19:51:50 pgsql Exp $ * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.110 2003/12/17 17:07:48 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -545,6 +545,8 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels)
/* /*
* We should have a single rel at the final level. * We should have a single rel at the final level.
*/ */
if (joinitems[levels_needed] == NIL)
elog(ERROR, "failed to build any %d-way joins", levels_needed);
Assert(length(joinitems[levels_needed]) == 1); Assert(length(joinitems[levels_needed]) == 1);
rel = (RelOptInfo *) lfirst(joinitems[levels_needed]); rel = (RelOptInfo *) lfirst(joinitems[levels_needed]);

21
src/backend/optimizer/path/joinrels.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.64 2003/11/29 19:51:50 pgsql Exp $ * $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.65 2003/12/17 17:07:48 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -226,7 +226,24 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
} }
} }
if (result_rels == NIL) /*----------
* When IN clauses are involved, there may be no legal way to make
* an N-way join for some values of N. For example consider
*
* SELECT ... FROM t1 WHERE
* x IN (SELECT ... FROM t2,t3 WHERE ...) AND
* y IN (SELECT ... FROM t4,t5 WHERE ...)
*
* We will flatten this query to a 5-way join problem, but there are
* no 4-way joins that make_join_rel() will consider legal. We have
* to accept failure at level 4 and go on to discover a workable
* bushy plan at level 5.
*
* However, if there are no IN clauses then make_join_rel() should
* never fail, and so the following sanity check is useful.
*----------
*/
if (result_rels == NIL && root->in_info_list == NIL)
elog(ERROR, "failed to build any %d-way joins", level); elog(ERROR, "failed to build any %d-way joins", level);
} }