From aea60045cdcfaf16bfb0cc3ca6a2622c308b0667 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 8 Nov 2007 23:23:00 +0000 Subject: [PATCH] If an index depends on no columns of its table, give it a dependency on the whole table instead, to ensure that it goes away when the table is dropped. Per bug #3723 from Sam Mason. Backpatch as far as 7.4; AFAICT 7.3 does not have the issue, because it doesn't have general-purpose expression indexes and so there must be at least one column referenced by an index. --- src/backend/catalog/index.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 2dc8667b9b..10dc2e380c 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -40,6 +40,7 @@ #include "executor/executor.h" #include "miscadmin.h" #include "optimizer/clauses.h" +#include "optimizer/var.h" #include "parser/parse_expr.h" #include "storage/procarray.h" #include "storage/smgr.h" @@ -690,6 +691,8 @@ index_create(Oid heapRelationId, } else { + bool have_simple_col = false; + /* Create auto dependencies on simply-referenced columns */ for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++) { @@ -700,8 +703,29 @@ index_create(Oid heapRelationId, referenced.objectSubId = indexInfo->ii_KeyAttrNumbers[i]; recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO); + + have_simple_col = true; } } + + /* + * It's possible for an index to not depend on any columns of + * the table at all, in which case we need to give it a dependency + * on the table as a whole; else it won't get dropped when the + * table is dropped. This edge case is not totally useless; + * for example, a unique index on a constant expression can serve + * to prevent a table from containing more than one row. + */ + if (!have_simple_col && + !contain_vars_of_level((Node *) indexInfo->ii_Expressions, 0) && + !contain_vars_of_level((Node *) indexInfo->ii_Predicate, 0)) + { + referenced.classId = RelationRelationId; + referenced.objectId = heapRelationId; + referenced.objectSubId = 0; + + recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO); + } } /* Store dependency on operator classes */ -- 2.39.5