diff options
| -rw-r--r-- | src/backend/optimizer/path/joinrels.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c index 3b65940c298..5375dd9be8c 100644 --- a/src/backend/optimizer/path/joinrels.c +++ b/src/backend/optimizer/path/joinrels.c @@ -17,6 +17,7 @@ #include "optimizer/joininfo.h" #include "optimizer/pathnode.h" #include "optimizer/paths.h" +#include "utils/memutils.h" static void make_rels_by_clause_joins(PlannerInfo *root, @@ -933,11 +934,32 @@ is_dummy_rel(RelOptInfo *rel) } /* - * Mark a rel as proven empty. + * Mark a relation as proven empty. + * + * During GEQO planning, this can get invoked more than once on the same + * baserel struct, so it's worth checking to see if the rel is already marked + * dummy. + * + * Also, when called during GEQO join planning, we are in a short-lived + * memory context. We must make sure that the dummy path attached to a + * baserel survives the GEQO cycle, else the baserel is trashed for future + * GEQO cycles. On the other hand, when we are marking a joinrel during GEQO, + * we don't want the dummy path to clutter the main planning context. Upshot + * is that the best solution is to explicitly make the dummy path in the same + * context the given RelOptInfo is in. */ static void mark_dummy_rel(RelOptInfo *rel) { + MemoryContext oldcontext; + + /* Already marked? */ + if (is_dummy_rel(rel)) + return; + + /* No, so choose correct context to make the dummy path in */ + oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel)); + /* Set dummy size estimate */ rel->rows = 0; @@ -949,6 +971,8 @@ mark_dummy_rel(RelOptInfo *rel) /* Set or update cheapest_total_path */ set_cheapest(rel); + + MemoryContextSwitchTo(oldcontext); } |