The discussions I've seen indicated that, in use, tablespaces were at the database level, but, yes, the docs do say that a table can be assigned to a defined tablespace. What I still can't find is syntax which establishes buffers/caches/whatever and assigns them to tablespaces. Without that, I'm not sure what benefit there is to tablespaces, other than a sort of RAID-lite. Robert ---- Original message ---- >Date: Tue, 12 Oct 2010 08:34:23 -0400 >From: pgsql-performance-owner@xxxxxxxxxxxxxx (on behalf of Robert Haas <robertmhaas@xxxxxxxxx>) >Subject: Re: How does PG know if data is in memory? >To: gnuoytr@xxxxxxx >Cc: pgsql-performance@xxxxxxxxxxxxxx > >On Mon, Oct 11, 2010 at 11:11 PM, <gnuoytr@xxxxxxx> wrote: >> An approach that works can be found in DB2, and likely elsewhere. >> >> The key is that tablespaces/tables/indexes/buffers are all attached through the bufferpool (the DB2 term). A tablespace/bufferpool match is defined. Then tables and indexes are assigned to the tablespace (and implicitly, the bufferpool). As a result, one can effectively pin data in memory. This is very useful, but not low hanging fruit to implement. >> >> The introduction of rudimentary tablespaces is a first step. I assumed that the point was to get to a DB2-like structure at some point. Yes? > >We already have tablespaces, and our data already is accessed through >the buffer pool. > >-- >Robert Haas >EnterpriseDB: http://www.enterprisedb.com >The Enterprise PostgreSQL Company > >-- >Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) >To make changes to your subscription: >http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
