Re: [PERFORM] PostgreSQL performance in simple queries

Neil Conway wrote: PostgreSQL (< 7.5) won't consider using an indexscan when the predicate involves an integer literal and the column datatype is int2 or int8. Is this fixed for 7.5? It isn't checked off on the TODO list at http://developer.postgresql.org/todo.php ---(end

Re: [PERFORM] Wierd context-switching issue on Xeon

In an attempt to throw the authorities off his trail, [EMAIL PROTECTED] (Tom Lane) transmitted: > ObQuote: "Research is what I am doing when I don't know what I am > doing." - attributed to Werner von Braun, but has anyone got a > definitive reference?

Re: [PERFORM] Wierd context-switching issue on Xeon

On Wed, 2004-05-19 at 21:59, Robert Creager wrote: > When grilled further on (Wed, 19 May 2004 21:20:20 -0400 (EDT)), > Bruce Momjian <[EMAIL PROTECTED]> confessed: > > > > > Did we ever come to a conclusion about excessive SMP context switching > > under load? > > > > I just figured out what w

Re: [PERFORM] Wierd context-switching issue on Xeon

OK, added to TODO: * Investigate SMP context switching issues --- Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Tom Lane wrote: > >> ... The SMP issue seems to be not with whether there is > >> i

Re: [PERFORM] Wierd context-switching issue on Xeon

Tom Lane wrote: > Robert Creager <[EMAIL PROTECTED]> writes: > > Tom Lane <[EMAIL PROTECTED]> confessed: > >> Do you have the post-7.4.2 datatype fixes for pg_autovacuum? > > > No. I'm still running 7.4.1 w/associated contrib. I guess an upgrade is in > > order then. I'm currently downloading 7

Re: [PERFORM] Wierd context-switching issue on Xeon

Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> ... The SMP issue seems to be not with whether there is >> instantaneous contention for the locked datastructure, but with the cost >> of making it possible for processor B to acquire a lock recently held by >> processor A. > I see.

Re: [PERFORM] Wierd context-switching issue on Xeon

Robert Creager <[EMAIL PROTECTED]> writes: > Tom Lane <[EMAIL PROTECTED]> confessed: >> Do you have the post-7.4.2 datatype fixes for pg_autovacuum? > No. I'm still running 7.4.1 w/associated contrib. I guess an upgrade is in > order then. I'm currently downloading 7.4.2 to see what the change

Re: [PERFORM] Wierd context-switching issue on Xeon

When grilled further on (Wed, 19 May 2004 22:42:26 -0400), Tom Lane <[EMAIL PROTECTED]> confessed: > Robert Creager <[EMAIL PROTECTED]> writes: > > I just figured out what was causing the problem on my system Monday. > > I'm using the pg_autovacuum daemon, and it was not vacuuming my db. > > Do y

Re: [PERFORM] Wierd context-switching issue on Xeon

Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Did we ever come to a conclusion about excessive SMP context switching > > under load? > > Yeah: it's bad. > > Oh, you wanted a fix? That seems harder :-(. AFAICS we need a redesign > that causes less load on the BufMgrLock. Howev

Re: [PERFORM] Wierd context-switching issue on Xeon

Robert Creager <[EMAIL PROTECTED]> writes: > I just figured out what was causing the problem on my system Monday. > I'm using the pg_autovacuum daemon, and it was not vacuuming my db. Do you have the post-7.4.2 datatype fixes for pg_autovacuum? regards, tom lane -

Re: [PERFORM] Wierd context-switching issue on Xeon

Bruce Momjian <[EMAIL PROTECTED]> writes: > Did we ever come to a conclusion about excessive SMP context switching > under load? Yeah: it's bad. Oh, you wanted a fix? That seems harder :-(. AFAICS we need a redesign that causes less load on the BufMgrLock. However, the traditional solution to

Re: [PERFORM] Wierd context-switching issue on Xeon

When grilled further on (Wed, 19 May 2004 21:20:20 -0400 (EDT)), Bruce Momjian <[EMAIL PROTECTED]> confessed: > > Did we ever come to a conclusion about excessive SMP context switching > under load? > I just figured out what was causing the problem on my system Monday. I'm using the pg_autovac

Re: [PERFORM] Wierd context-switching issue on Xeon

Did we ever come to a conclusion about excessive SMP context switching under load? --- Dave Cramer wrote: > Robert, > > The real question is does it help under real life circumstances ? > > Did you do the tests with Tom's

Re: [PERFORM] PostgreSQL performance in simple queries

Try using select * from files_t where parent = ::int8 You have declared parent as int8, but the query will assume int4 for "" and may not use the index. Also make sure you have ANALYZEd this table. Regards, Gary. On 20 May 2004 at 0:07, Eugeny Balakhonov wrote: > Hello for

[PERFORM] shared buffer size on linux

See http://kerneltrap.org/node/view/3148, about 40% down, under the header "2.6 -aa patchset, object-based reverse mapping". Does this mean that the more shared memory the bigger the potential for a swap storm? ---(end of broadcast)--- TIP 6: Have

Re: [PERFORM] PostgreSQL performance in simple queries

Eugeny Balakhonov wrote: I tries to run simple query: select * from files_t where parent = Use this instead: select * from files_t where parent = ''; ("parent = ::int8" would work as well.) PostgreSQL (< 7.5) won't consider using an indexscan when the predicate involves an integer lit

[PERFORM] PostgreSQL performance in simple queries

Hello for all! I have PostgreSQL 7.4 under last version of Cygwin and have some problems with performance :( It is very strange... I don't remember this problem on previous version Cygwin and PostgreSQL 7.3 I have only two simple tables: CREATE TABLE public.files_t ( id int8 NOT NULL, paren

Re: [PERFORM] DB Design

On Wed, 2004-05-19 at 15:37 +0800, Michael Ryan S. Puncia wrote: > Hi Guys, > > > > My question is .. which is better design > > > > 1. Single Table with 50 million records or > 2. Multiple Table using inheritance to the parents table It's not that simple. Given your e-m

[PERFORM] DB Design

Hi Guys,      My question is .. which is better design   Single Table with 50 million records or Multiple Table using inheritance to the parents table     I will use this only for query purpose ..   Thanks ..