On 2021-04-06 01:34:02 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On 2021-04-06 00:47:13 -0400, Tom Lane wrote: > >> Not wanting to distract from your point about xactCompletionCount, > >> but ... I wonder if we could get away with defining "isObjectPinned" > >> as "is the OID <= 9999" (and, in consequence, dropping explicit pin > >> entries from pg_depend). I had not previously seen a case where the > >> cost of looking into pg_depend for this info was this much of the > >> total query runtime. > > > Couldn't we also treat FirstGenbkiObjectId to FirstBootstrapObjectId as > > pinned? That'd be another 400kB of database size... > > Yeah, it'd require some close study of exactly what we want to pin > or not pin.
One interesting bit is: postgres[947554][1]=# SELECT classid::regclass, objid, refclassid::regclass, refobjid, deptype, refobjversion FROM pg_depend WHERE refobjid < 13000 AND deptype <> 'p'; ┌───────────────┬───────┬──────────────┬──────────┬─────────┬───────────────┐ │ classid │ objid │ refclassid │ refobjid │ deptype │ refobjversion │ ├───────────────┼───────┼──────────────┼──────────┼─────────┼───────────────┤ │ pg_constraint │ 15062 │ pg_collation │ 100 │ n │ 2.31 │ └───────────────┴───────┴──────────────┴──────────┴─────────┴───────────────┘ (1 row) > Certainly everything with hand-assigned OIDs should > be pinned, but I think there's a lot of critical stuff like index > opclasses that don't get hand-assigned OIDs. On the other hand, > it's intentional that nothing in information_schema is pinned. Isn't that pretty much the difference between FirstGenbkiObjectId and FirstBootstrapObjectId? Genbki will have assigned things like opclasses, but not things like information_schema? > We might have to rejigger initdb so that there's a clearer > distinction between the OID ranges we want to pin or not. > Maybe we'd even get initdb to record the cutoff OID in > pg_control or someplace. The only non-pinned pg_depend entry below FirstBootstrapObjectId is the collation versioning one above. The only pinned entries above FirstBootstrapObjectId are the ones created via system_constraints.sql. So it seems we "just" would need to resolve the constraint versioning stuff? And that could probably just be handled as a hardcoded special case for now... Greetings, Andres Freund
