On Sun, Nov 7, 2010 at 10:03 PM, Cédric Villemain <cedric.villemain.deb...@gmail.com> wrote: > 2010/11/8 Mark Rostron <mrost...@ql2.com>: >>> > >>> > What is the procedure that postgres uses to decide whether or not a >>> > table/index block will be left in the shared_buffers cache at the end >>> > of the operation? >>> > >>> >>> The only special cases are for sequential scans and VACUUM, which use >>> continuously re-use a small section of the buffer cache in some cases >>> instead. >> >> Thanks - the part about sequential scans and the re-use of a small section >> of shared_buffers is the bit I was interested in. >> I don't suppose you would be able to tell me how large that re-useable area >> might be? > > There are 256KB per seqscan and 256KB per vacuum. > > I suggest you to go reading src/backend/storage/buffer/README
Note that there is a different, higher limit for the "bulk write" strategy when using COPY IN or CTAS. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
