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Lock table in DROP STATISTICS

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The DROP STATISTICS code failed to properly lock the table, leading to

  ERROR:  tuple concurrently deleted

when executed concurrently with ANALYZE.

Fixed by modifying RemoveStatisticsById() to acquire the same lock as
ANALYZE. This function is called only by DROP STATISTICS, as ANALYZE
calls RemoveStatisticsDataById() directly.

Reported by Justin Pryzby, fix by me. Backpatch through 12. The code was
like this since it was introduced in 10, but older releases are EOL.

Reported-by: Justin Pryzby
Reviewed-by: Tom Lane
Backpatch-through: 12

Discussion: https://postgr.es/m/ZUuk-8CfbYeq6g_u@pryzbyj2023
This commit is contained in:
Tomas Vondra 2023-11-19 21:03:29 +01:00
parent fc3f862bab
commit 9dd50e92ed
1 changed files with 29 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
src/backend/commands/statscmds.c
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@ -722,20 +722,14 @@ AlterStatistics(AlterStatsStmt *stmt)
}
/*
* Guts of statistics object deletion.
* Delete entry in pg_statistic_ext_data catalog.
*/
void
RemoveStatisticsById(Oid statsOid)
static void
RemoveStatisticsDataById(Oid statsOid)
{
Relation relation;
HeapTuple tup;
Form_pg_statistic_ext statext;
Oid relid;
/*
* First delete the pg_statistic_ext_data tuple holding the actual
* statistical data.
*/
relation = table_open(StatisticExtDataRelationId, RowExclusiveLock);
tup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statsOid));
@ -748,6 +742,19 @@ RemoveStatisticsById(Oid statsOid)
ReleaseSysCache(tup);
table_close(relation, RowExclusiveLock);
}
/*
* Guts of statistics object deletion.
*/
void
RemoveStatisticsById(Oid statsOid)
{
Relation relation;
Relation rel;
HeapTuple tup;
Form_pg_statistic_ext statext;
Oid relid;
/*
* Delete the pg_statistic_ext tuple. Also send out a cache inval on the
@ -763,12 +770,24 @@ RemoveStatisticsById(Oid statsOid)
statext = (Form_pg_statistic_ext) GETSTRUCT(tup);
relid = statext->stxrelid;
/*
* Delete the pg_statistic_ext_data tuple holding the actual statistical
* data. We lock the user table first, to prevent other processes (e.g.
* DROP STATISTICS) from removing the row concurrently.
*/
rel = table_open(relid, ShareUpdateExclusiveLock);
RemoveStatisticsDataById(statsOid);
CacheInvalidateRelcacheByRelid(relid);
CatalogTupleDelete(relation, &tup->t_self);
ReleaseSysCache(tup);
/* Keep lock until the end of the transaction. */
table_close(rel, NoLock);
table_close(relation, RowExclusiveLock);
}