Re: BUG #17212: pg_amcheck fails on checking temporary relations

Mark Dilger <mark.dilger@enterprisedb.com>

From: Mark Dilger <mark.dilger@enterprisedb.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Alexander Lakhin <exclusion@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Date: 2021-10-05T03:19:02Z
Lists: pgsql-bugs, pgsql-hackers

> On Oct 4, 2021, at 6:19 PM, Peter Geoghegan <pg@bowt.ie> wrote:
> 
> I don't see what the point of this example is.

It doesn't matter.

I am changing pg_amcheck to filter out indexes as you say.  Since the btree check should no longer error in these cases, the issue of pg_amcheck exit(2) sorts itself out without further code changes.

I am changing verify_heapam to skip unlogged tables during recovery.  In testing, checking such a table results in a simple notice:

  NOTICE:  cannot verify unlogged relation "u_tbl" during recovery, skipping

While testing, I also created an index on the unlogged table and checked that index using bt_index_parent_check, and was surprised that checking it using bt_index_parent_check raises an error:

  ERROR:  cannot acquire lock mode ShareLock on database objects while recovery is in progress
  HINT:  Only RowExclusiveLock or less can be acquired on database objects during recovery.

It doesn't get as far as btree_index_mainfork_expected().  So I am changing pg_amcheck to filter out indexes when pg_is_in_recovery() is true and relpersistence='u'.  Does that sound right to you?

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company






Commits

  1. Remove unstable pg_amcheck tests.

  2. pg_amcheck: avoid unhelpful verification attempts.

  3. amcheck: Skip unlogged relations in Hot Standby.

  4. amcheck: Skip unlogged relations during recovery.