Alvaro Herrera wrote:
On Thu, Jun 16, 2005 at 04:20:34PM +1000, Gavin Sherry wrote:
2) By no fault of its own, autovacuum's level of granularity is the table
level. For people dealing with non-trivial amounts of data (and we're not
talking gigabytes or terabytes here), this is a serious drawback. Vacuum
at peak times can cause very intense IO bursts -- even with the
enhancements in 8.0. I don't think the solution to the problem is to give
users the impression that it is solved and then vacuum their tables during
peak periods. I cannot stress this enough.
People running systems with petabyte-sized tables can disable autovacuum
for those tables, and leave it running for the rest. Then they can
schedule whatever maintenance they see fit on their gigantic tables.
Trying to run a database with more than a dozen gigabytes of data
without expert advice (or at least reading the manual) would be
extremely stupid anyway.
professional advice won't help you here because you still have to vacuum
this giant table. this is especially critical in case of 24x7 systems
(which are quite frequent). in many cases there is no maintenance window
anymore (e.g. a wastewater system will be only 24x7).
reducing the impact of vacuum and "create index" would be important to
many people. to me improving vacuum it is as important as Jan's bgwriter
patch (it reduces the troubles people had with checkpoints).
best regards,
hans
--
Cybertec Geschwinde u Schoenig
Schoengrabern 134, A-2020 Hollabrunn, Austria
Tel: +43/664/393 39 74
www.cybertec.at, www.postgresql.at
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