Re: Berserk Autovacuum (let's save next Mandrill)

On Mon, Mar 23, 2020 at 02:27:29PM +0100, Laurenz Albe wrote:
> Here is version 10 of the patch, which uses a scale factor of 0.2.

Thanks

> Any table that has received more inserts since it was
> last vacuumed (and that is not vacuumed for another
> reason) will be autovacuumed.

Since this vacuum doesn't trigger any special behavior (freeze), you can remove
the parenthesized part: "(and that is not vacuumed for another reason)".

Maybe in the docs you can write this with thousands separators: 10,000,000

It looks like the GUC uses scale factor max=1e10, but the relopt is still
max=100, which means it's less possible to disable for a single rel.

> +++ b/src/backend/access/common/reloptions.c
> @@ -398,6 +407,15 @@ static relopt_real realRelOpts[] =
> },
> -1, 0.0, 100.0
> },
> + {
> + {
> + "autovacuum_vacuum_insert_scale_factor",
> + "Number of tuple inserts prior to vacuum as a fraction of reltuples",
> + RELOPT_KIND_HEAP | RELOPT_KIND_TOAST,
> + ShareUpdateExclusiveLock
> + },
> + -1, 0.0, 100.0
> + },
> {
> {
> "autovacuum_analyze_scale_factor",

> +++ b/src/backend/utils/misc/guc.c
> @@ -3549,6 +3558,17 @@ static struct config_real ConfigureNamesReal[] =
> 0.2, 0.0, 100.0,
> NULL, NULL, NULL
> },
> +
> + {
> + {"autovacuum_vacuum_insert_scale_factor", PGC_SIGHUP, AUTOVACUUM,
> + gettext_noop("Number of tuple inserts prior to vacuum as a fraction of reltuples."),
> + NULL
> + },
> + &autovacuum_vac_ins_scale,
> + 0.2, 0.0, 1e10,
> + NULL, NULL, NULL
> + },
> +
> {
> {"autovacuum_analyze_scale_factor", PGC_SIGHUP, AUTOVACUUM,
> gettext_noop("Number of tuple inserts, updates, or deletes prior to analyze as a fraction of reltuples."),