Uh, was this ever addressed? I don't see the patch applied or the code in this area modified.
--------------------------------------------------------------------------- On Thu, May 24, 2018 at 04:33:11PM +0200, Laurenz Albe wrote: > While looking at this: > https://stackoverflow.com/q/50413623/6464308 > I realized that "LOCK TABLE <unlogged table>" puts a > Standby/LOCK into the WAL stream, which causes a log flush > at COMMIT time. > > That hurts performance, and I doubt that it is necessary. > At any rate, DROP TABLE on an unlogged table logs nothing. > > The attached patch would take care of it, but I'm not sure > if that's the right place to check. > > Yours, > Laurenz Albe > From d474e7b41298944e43bb9141eb33adbdd9ea1098 Mon Sep 17 00:00:00 2001 > From: Laurenz Albe <laurenz.a...@cybertec.at> > Date: Tue, 22 May 2018 18:13:31 +0200 > Subject: [PATCH] Don't log locks on unlogged tables > > --- > src/backend/storage/lmgr/lock.c | 28 +++++++++++++++++++++------- > 1 file changed, 21 insertions(+), 7 deletions(-) > > diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c > index dc3d8d9817..70cac47ab3 100644 > --- a/src/backend/storage/lmgr/lock.c > +++ b/src/backend/storage/lmgr/lock.c > @@ -37,6 +37,7 @@ > #include "access/twophase_rmgr.h" > #include "access/xact.h" > #include "access/xlog.h" > +#include "catalog/pg_class.h" > #include "miscadmin.h" > #include "pg_trace.h" > #include "pgstat.h" > @@ -47,6 +48,7 @@ > #include "storage/standby.h" > #include "utils/memutils.h" > #include "utils/ps_status.h" > +#include "utils/rel.h" > #include "utils/resowner_private.h" > > > @@ -1041,13 +1043,25 @@ LockAcquireExtended(const LOCKTAG *locktag, > */ > if (log_lock) > { > - /* > - * Decode the locktag back to the original values, to avoid > sending > - * lots of empty bytes with every message. See lock.h to check > how a > - * locktag is defined for LOCKTAG_RELATION > - */ > - LogAccessExclusiveLock(locktag->locktag_field1, > - > locktag->locktag_field2); > + bool unlogged_rel = false; > + > + if (locktag->locktag_type == LOCKTAG_RELATION) > + { > + Relation r = > RelationIdGetRelation(locktag->locktag_field2); > + unlogged_rel = r->rd_rel->relpersistence == > RELPERSISTENCE_UNLOGGED; > + RelationClose(r); > + } > + > + if (!unlogged_rel) > + { > + /* > + * Decode the locktag back to the original values, to > avoid sending > + * lots of empty bytes with every message. See lock.h > to check how a > + * locktag is defined for LOCKTAG_RELATION > + */ > + LogAccessExclusiveLock(locktag->locktag_field1, > + > locktag->locktag_field2); > + } > } > > return LOCKACQUIRE_OK; > -- > 2.14.3 > -- Bruce Momjian <br...@momjian.us> https://momjian.us EDB https://enterprisedb.com Only you can decide what is important to you.
