[PERFORM] Pushing LIMIT into sub-queries of a UNION ALL

2011-05-21 Thread Dave Johansen
I am using Postgres 8.3 and I have an issue very closely related to the one described here: http://archives.postgresql.org/pgsql-general/2005-06/msg00488.php Basically, I have a VIEW which is a UNION ALL of two tables but when I do a select on the view using a LIMIT, it scans the entire tables and

[PERFORM] Performance degradation of inserts when database size grows

2011-05-21 Thread Andrey Vorobiev
Hi, guys. I have following environment configuration - Postgres 8.4.7 with following postresql.conf settings modified: listen_addresses = '*' max_connections = 100 shared_buffers = 2048MB max_prepared_transactions = 100 wal_buffers = 1024kB checkpoi

[PERFORM] Pushing LIMIT into sub-queries of a UNION ALL?

2011-05-21 Thread Dave Johansen
I am using Postgres 8.3 and I have an issue very closely related to the one described here: http://archives.postgresql.org/pgsql-general/2005-06/msg00488.php Basically, I have a VIEW which is a UNION ALL of two tables but when I do a select on the view using a LIMIT, it scans the entire tables and

Re: [PERFORM] Modifying shared_buffers causes despite plenty of ram

2011-05-21 Thread STA
On May 17, 1:00 pm, STA wrote: > Hi - Linux newbie here, and more of a developer than pgsql SysAdmin... > Sorry... title should be "... causes error on startup" or something. I accidentally clicked submit before I'd decided what the title should be. :) -- Sent via pgsql-performance mailing list

[PERFORM] Modifying shared_buffers causes despite plenty of ram

2011-05-21 Thread STA
Hi - Linux newbie here, and more of a developer than pgsql SysAdmin... When trying to follow some performance tuning suggestions by Robert Haas here: http://www.linux.com/learn/tutorials/394523-configuring-postgresql-for-pretty-good-performance This is with PgSql 9.0.3 running on the Amazon EC2 o

Re: [PERFORM] Modifying shared_buffers causes despite plenty of ram

2011-05-21 Thread STA
On May 17, 1:02 pm, STA wrote: > On May 17, 1:00 pm, STA wrote: > > > Hi - Linux newbie here, and more of a developer than pgsql SysAdmin... > > Sorry... title should be "... causes error on startup" or something. I > accidentally clicked submit before I'd decided what the title should > be. :)

FW: [PERFORM] KVP table vs. hstore - hstore performance (Was: Postgres NoSQL emulation)

2011-05-21 Thread m1ott
Hi Merlin The analyze command gave the following result: On the KVP table: Index Scan using kvpidx on bench_kvp (cost=0.00..8.53 rows=1 width=180) (actual time=0.037..0.038 rows=1 loops=1) Index Cond: (bench_id = '20_20'::text) Total runtime: 0.057 ms And on the Hstore table: Bitmap Hea

[PERFORM] [OT]: Confidentiality disclosures in list posts (Was: SORT performance - slow?)

2011-05-21 Thread Lew
Kevin Grittner wrote: "Strange, John W" wrote: If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. You probably already know this, but jus

Re: [PERFORM] Postgres refusing to use >1 core

2011-05-21 Thread Aren Cambre
Just want to again say thanks for this query. It seriously sped up part of my program. Aren On Thu, May 12, 2011 at 1:27 PM, Aren Cambre wrote: > This is a perfect example of a place where you could push some work out of >> the application and into the database. You can consolidate your 1 to 10

Re: [PERFORM] Performance degradation of inserts when database size grows

2011-05-21 Thread Leonardo Francalanci
>1. How does database size affect insert performance? >2. Why does number of written buffers increase when database size grows? It might be related to indexes. Indexes size affect insert performance. >3. How can I further analyze this problem? Try without indexes? -- Sent via pgsql-performa