pgsql: Lock table in DROP STATISTICS

Lock table in DROP STATISTICS

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

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/28f84f72fbafe3bef675d3a176eb53177f4a9433

Modified Files
--------------
src/backend/commands/statscmds.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)