Re: GIN fast-insert vs autovacuum scheduling

Tom Lane wrote:

> On top of those issues, there are implementation problems in the
> proposed relation_has_pending_indexes() check: it has hard-wired
> knowledge about GIN indexes, which means the feature cannot be
> extended to add-on index AMs; and it's examining indexes without any
> lock whatsoever on either the indexes or their parent table.  (And
> we really would rather not let autovacuum take a lock here.)

I wonder if it's workable to have GIN send pgstats a message with number
of fast-inserted tuples, and have autovacuum check that number as well
as dead/live tuples.

ISTM this shouldn't be considered part of either vacuum or analyze at
all, and have autovacuum invoke it separately from both, with its own
decision equations and such.  We could even have a scan over pg_class
just for GIN indexes to implement this.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support