Re: [HACKERS] Logical Replication WIP

In 0001-Add-PUBLICATION-catalogs-and-DDL-v16.patch.gz,

+static bool
+is_publishable_class(Oid relid, Form_pg_class reltuple)
+{
+       return reltuple->relkind == RELKIND_RELATION &&
+               !IsCatalogClass(relid, reltuple) &&
+               reltuple->relpersistence == RELPERSISTENCE_PERMANENT &&
+               /* XXX needed to exclude information_schema tables */
+               relid >= FirstNormalObjectId;
+}

I don't think the XXX part is necessary, because IsCatalogClass()
already checks for the same thing.  (The whole thing is a bit bogus
anyway, because you can drop and recreate the information schema at run
time without restriction.)

+#define MAX_RELCACHE_INVAL_MSGS 100
+       List    *relids = GetPublicationRelations(HeapTupleGetOid(tup));
+
+       /*
+        * We don't want to send too many individual messages, at some point
+        * it's cheaper to just reset whole relcache.
+        *
+        * XXX: the MAX_RELCACHE_INVAL_MSGS was picked arbitrarily, maybe
+        * there is better limit.
+        */
+       if (list_length(relids) < MAX_RELCACHE_INVAL_MSGS)

Do we have more data on this?  There are people running with 100000
tables, and changing a publication with a 1000 tables would blow all
that away?

Maybe at least it should be set relative to INITRELCACHESIZE (400) to
tie things together a bit?

Update the documentation of SharedInvalCatalogMsg in sinval.h for the
"all relations" case.  (Maybe look around the whole file to make sure
comments are still valid.)

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services