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authorTomas Vondra <tomas.vondra@postgresql.org>2021-09-20 00:34:57 +0200
committerTomas Vondra <tomas.vondra@postgresql.org>2021-09-20 00:34:57 +0200
commitc9eeef2a15c02ff7dd2bf3251dbee925b050fc0f (patch)
tree52e6559cacf62a8e13636f67d3bb16199d453872 /src/backend
parentd5eeb51bc053d75f647136026de522d6ee3bf725 (diff)
downloadpostgresql-c9eeef2a15c02ff7dd2bf3251dbee925b050fc0f.tar.gz
postgresql-c9eeef2a15c02ff7dd2bf3251dbee925b050fc0f.zip
Disallow extended statistics on system columns
Since introduction of extended statistics, we've disallowed references to system columns. So for example CREATE STATISTICS s ON ctid FROM t; would fail. But with extended statistics on expressions, it was possible to work around this limitation quite easily CREATE STATISTICS s ON (ctid::text) FROM t; This is an oversight in a4d75c86bf, fixed by adding a simple check. Backpatch to PostgreSQL 14, where support for extended statistics on expressions was introduced. Backpatch-through: 14 Discussion: https://postgr.es/m/20210816013255.GS10479%40telsasoft.com
Diffstat (limited to 'src/backend')
-rw-r--r--src/backend/commands/statscmds.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 78917844dee..afe6744e237 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -288,9 +288,24 @@ CreateStatistics(CreateStatsStmt *stmt)
Node *expr = selem->expr;
Oid atttype;
TypeCacheEntry *type;
+ Bitmapset *attnums = NULL;
+ int k;
Assert(expr != NULL);
+ /* Disallow expressions referencing system attributes. */
+ pull_varattnos(expr, 1, &attnums);
+
+ k = -1;
+ while ((k = bms_next_member(attnums, k)) >= 0)
+ {
+ AttrNumber attnum = k + FirstLowInvalidHeapAttributeNumber;
+ if (attnum <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("statistics creation on system columns is not supported")));
+ }
+
/*
* Disallow data types without a less-than operator.
*