On 2016-08-29 03:26:06 +0200, Vik Fearing wrote: > The attached two patches scratch two itches I've been having for a > while. I'm attaching them together because the second depends on the first. > > Both deal with the fact that [auto]vacuum has taken on more roles than > its original purpose. > > > Patch One: autovacuum insert-heavy tables > > If you have a table that mostly receives INSERTs, it will never get > vacuumed because there are no (or few) dead rows. I have added an > "inserts_since_vacuum" field to PgStat_StatTabEntry which works exactly > the same way as "changes_since_analyze" does. > > The reason such a table needs to be vacuumed is currently twofold: the > visibility map is not updated, slowing down index-only scans; and BRIN > indexes are not maintained, rendering them basically useless.
> Patch Two: autovacuum after table rewrites > > This patch addresses the absurdity that a standard VACUUM is required > after a VACUUM FULL because the visibility map gets blown away. This is > also the case for CLUSTER and some versions of ALTER TABLE that rewrite > the table.
I think this should rather fixed by maintaining the VM during cluster.
+1
IIRC there was an attempt late in the 9.5 cycle, but Bruce
(IIRC) ran out of steam. And nobody picked it up again ... :(
