"Pavan Deolasee" <[EMAIL PROTECTED]> writes: > 1. Before VACUUM starts, it updates the pg_class row of the target > table, noting that VACUUM_IN_PROGRESS for the target table.
If I understand correctly nobody would be able to re-use any line-pointers when a vacuum is in progress? I find that a bit scary since for large tables you may actually always be running a vacuum. Perhaps the DSM will fix that but for heavily updated tables I think you might still be pretty much continuously running vacuum. On the other hand it would just result in line pointer bloat. And I think VACUUM could still safely remove old dead line pointers if it noted that the table had a clean vacuum status when it started. > 2. It then waits for all the existing transactions to finish to make > sure that everyone can see the change in the pg_class row, I'm a bit scared of how many "waits for all transactions to finish" we're accumulating. It seemed safe enough when we had only one but I'm not sure what the consequences for this action are when there are several of them. Are we perhaps creating deadlocks? -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's PostGIS support! -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
