Re: [SQL] Performance - Mailing list pgsql-sql
From | Jason Slagle |
---|---|
Subject | Re: [SQL] Performance |
Date | |
Msg-id | Pine.LNX.4.03.9903101351310.20770-100000@tacorp.net Whole thread Raw |
In response to | Re: [SQL] Performance (Karl Denninger <karl@Denninger.Net>) |
List | pgsql-sql |
And there off :D Reloading it. We'll try again :blah: Thanks, Jason --- Jason Slagle Network Administrator - Toledo Internet Access - Toledo Ohio - raistlin@tacorp.net - jslagle@toledolink.com - WHOIS JS10172 On Wed, 10 Mar 1999, Karl Denninger wrote: > That's a waste - a vacuum on a table with no deletes having been executed > and no indices will go through everything and do absolutely nothing :-) > > -- > -- > Karl Denninger (karl@denninger.net) http://www.mcs.net/~karl > I ain't even *authorized* to speak for anyone other than myself, so give > up now on trying to associate my words with any particular organization. > > > On Wed, Mar 10, 1999 at 01:39:19PM -0500, Jason Slagle wrote: > > Haven't created any yet, as I have not yet determined what I want to index > > on. I just created the database and bulk loaded 211 megs of : delimited > > data, generating a 350 meg file in the data dir. It has been vacuuming > > for 45 mins or so now... Prob needs more horsepower :D > > > > Jason > > > > --- > > Jason Slagle > > Network Administrator - Toledo Internet Access - Toledo Ohio > > - raistlin@tacorp.net - jslagle@toledolink.com - WHOIS JS10172 > > > > On Wed, 10 Mar 1999, Karl Denninger wrote: > > > > > Depends on the indices that have to be gone through. It can take quite a > > > while. > > > > > > -- > > > -- > > > Karl Denninger (karl@denninger.net) http://www.mcs.net/~karl > > > I ain't even *authorized* to speak for anyone other than myself, so give > > > up now on trying to associate my words with any particular organization. > > > > > > > > > On Wed, Mar 10, 1999 at 01:27:20PM -0500, Jason Slagle wrote: > > > > And how long is normal for Vacuum analyze to take on bout 350 megs of > > > > DATA? > > > > > > > > Jason > > > > > > > > --- > > > > Jason Slagle > > > > Network Administrator - Toledo Internet Access - Toledo Ohio > > > > - raistlin@tacorp.net - jslagle@toledolink.com - WHOIS JS10172 > > > > > > > > On Wed, 10 Mar 1999, Tom Lane wrote: > > > > > > > > > "Brett W. McCoy" <bmccoy@lan2wan.com> writes: > > > > > >> I have 1,400,000 entries (200MB) I'm inserting into a database. Radius > > > > > >> detail files as a matter of fact. Apart from COPY taking forever to load > > > > > >> that (probably due to my several indexes), it seems the select is VERY > > > > > >> slow. Any tips? > > > > > > > > > > > I found that if you create an index before doing a bulk COPY, yes, it does > > > > > > take forever to load, and the select is slow. What I did was drop the > > > > > > indices built from the COPY and rebuild them. Speeded the selects up > > > > > > significantly. So now I don't build any indices until after I load my > > > > > > huge databases in. > > > > > > > > > > Not building the indexes until you've done the bulk load is good advice; > > > > > it does seem a lot faster to build an index on an already-loaded table > > > > > than to construct it piecemeal during the COPY. However, either way > > > > > should result in the same index, so I don't see why it'd affect the > > > > > speed of a subsequent SELECT. Did you remember to do VACUUM ANALYZE > > > > > both times? The system is likely to ignore the index until you have > > > > > vacuumed the table. > > > > > > > > > > In short, best bulk load procedure is > > > > > > > > > > CREATE TABLE ... > > > > > COPY ... > > > > > CREATE INDEX(es) on table > > > > > Repeat as needed for all tables being bulk-loaded > > > > > VACUUM ANALYZE > > > > > > > > > > BTW, if you use pg_dump to dump and reload a big database, pg_dump > > > > > knows about the create-indexes-last trick. But it doesn't do a VACUUM > > > > > for you; you have to do that by hand after running the reload script, > > > > > or your database will be slow. > > > > > > > > > > regards, tom lane > > > > > > > > > > > > > > > > > > >