On Wed, 2020-03-25 at 23:19 +0300, Alexander Korotkov wrote: > On Wed, Mar 25, 2020 at 10:26 PM Andres Freund <and...@anarazel.de> wrote: > > On 2020-03-25 11:05:21 -0500, Justin Pryzby wrote: > > > Since we talked about how scale_factor can be used to effectively disable > > > this > > > new feature, I thought that scale=100 was too small and suggesed 1e10 > > > (same as > > > max for vacuum_cleanup_index_scale_factor since 4d54543ef). That should > > > allow > > > handling the case that analyze is disabled, or its threshold is high, or > > > it > > > hasn't run yet, or it's running but hasn't finished, or analyze is > > > triggered as > > > same time as vacuum. > > > > For disabling we instead should allow -1, and disable the feature if set > > to < 0. > > This patch introduces both GUC and reloption. In reloptions we > typically use -1 for "disable reloption, use GUC value instead" > semantics. So it's unclear how should we allow reloption to both > disable feature and disable reloption. I think we don't have a > precedent in the codebase yet. We could allow -2 (disable reloption) > and -1 (disable feature) for reloption. Opinions?
Here is patch v11, where the reloption has the same upper limit 1e10 as the GUC. There is no good reason to have them different. I am reluctant to introduce new semantics like a reloption value of -2 to disable a feature in this patch right before feature freeze. I believe there are enough options to disable insert-only vacuuming for an individual table: - Set the threshold to 2147483647. True, that will not work for very large tables, but I think that there are few tables that insert that many rows before they hit autovacuum_freeze_max_age anyway. - Set the scale factor to some astronomical value. Yours, Laurenz Albe
