December 2008

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27 discussions - 243 posts

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55
Need help with 8.4 Performance Testing

Database performance geeks, We have a number of patches pending for 8.4 designed to improve database performance in a variety of circumstances. We need as many users as possible to build test ...

Josh Berkus
Dec 7, 2008 at 7:38 pm
Dec 14, 2008 at 5:49 am
32
Experience with HP Smart Array P400 and SATA drives?

Has anyone benchmarked this controller (PCIe/4x, 512 MB BBC)? We try to use it with 8x SATA 1TB drives in RAID-5 mode under Linux, and measure strange values. An individual drive is capable of ...

Mario Weilguni
Dec 2, 2008 at 9:22 am
Dec 11, 2008 at 1:47 pm
23
dbt-2 tuning results with postgresql-8.3.5

Hi all, So after a long hiatus after running this OLTP workload at the OSDL, many of you know the community has had some equipment donated by HP: a DL380 G5 and an MSA70 disk array. We are currently ...

Mark Wong
Dec 21, 2008 at 12:54 am
Feb 22, 2009 at 11:03 pm
20
Poor plan choice in prepared statement

Hi, I am re-posting my question here after trying to find a solution in the PHP pgsql list with no luck. I am experiencing some performance issues that I think are stemming from prepared statements. ...

Bricklen
Dec 30, 2008 at 6:59 pm
Jan 30, 2009 at 7:41 pm
11
query plan with index having a btrim is different for strings of different length

Hi, I've discovered a peculiarity with using btrim in an index and was wondering if anyone has any input. My table is like this: Table "public.m_object_paper" Column | Type | Modifiers ...

Richard Yen
Dec 9, 2008 at 10:33 pm
Dec 11, 2008 at 1:44 am
9
Slow table update

SQL: update product set sz_category_id=null where am_style_kw1 is not null and sz_category_id is not null query plan: "Seq Scan on product (cost=0.00..647053.30 rows=580224 width=1609)" " Filter: ...

Laszlo Nagy
Dec 22, 2008 at 11:06 am
Dec 29, 2008 at 1:30 pm
9
measure database contention

Hi, we have a some bad queries (developers are working on that), some of them run in 17 secs and that is the average but when analyzing logs i found that from time to time some of them took upto 3 ...

Jaime Casanova
Dec 16, 2008 at 7:34 pm
Dec 17, 2008 at 9:15 pm
9
Postgres using more memory than it should

Hi. I have a problem on one of our production servers. A fairly complicated query is running, and the backend process is using 30 GB of RAM. The machine only has 32GB, and is understandably swapping ...

Matthew Wakeling
Dec 3, 2008 at 4:01 pm
Dec 4, 2008 at 1:06 pm
9
analyzing intermediate query

I noticed that query SELECT dok.* FROM dok JOIN (SELECT DISTINCT dokumnr FROM temptbl ) x USING(dokumnr); is slow in 8.1.4 I cannot use explain analyze since this query uses results from temporary ...

Andrus
Dec 2, 2008 at 12:12 pm
Dec 2, 2008 at 9:22 pm
7
Troubles dumping a very large table.

(NOTE: I tried sending this email from my excite account and it appears to have been blocked for whatever reason. But if the message does get double posted, sorry for the inconvenience.) Hey all, ...

Ted Allen
Dec 24, 2008 at 5:36 pm
Dec 29, 2008 at 12:48 pm
7
Trigger function, bad performance

Hello, I'm having problems with the following bad performing select-statement in a trigger-function (on update before): ... for c in select id_country, sum(cost) as sum_cost from costs where id_user ...

Rogatzki Rainer
Dec 4, 2008 at 1:40 pm
Dec 5, 2008 at 3:41 pm
6
How to "unique-ify" HUGE table?

Hi everyone! I have a very large 2-column table (about 500M records) from which I want to remove duplicate records. I have tried many approaches, but they all take forever. The table's definition ...

Kynn Jones
Dec 23, 2008 at 5:25 pm
Dec 24, 2008 at 6:56 pm
3
Bgwriter and pg_stat_bgwriter.buffers_clean aspects

Hello. (Sorry, I have sent this letter to pgsql-general@ first and only then - noticed that there is a special performance mailing list. So I post it here now.) I am trying to tune PostgreSQL write ...

Dmitry Koterov
Dec 25, 2008 at 11:08 pm
Jan 7, 2009 at 6:23 am
3
Big index sizes

We have serveral table where the index size is much bigger than the table size. Example: select count(*) from product_price -- 2234244 Table size: 400 MB Index size: 600 MB After executing "reindex ...

Laszlo Nagy
Dec 30, 2008 at 9:06 am
Dec 30, 2008 at 3:39 pm
3
PostgreSQL vs Oracle

Hi, I am looking for some recent and hopefully genuine comparisons between Oracle and PostgreSQL regarding their performance in large scale applications. Tests from real world applications would be ...

Victor Nawothnig
Dec 21, 2008 at 8:17 am
Dec 22, 2008 at 3:31 am
3
How to profile an "SQL script"?

Hi. I have a longish collection of SQL statements stored in a file that I run periodically via cron. Running this "script" takes a bit too long, even for a cron job, and I would like to streamline ...

Kynn Jones
Dec 3, 2008 at 7:31 pm
Dec 4, 2008 at 12:03 am
2
db server load

Hi All, I would like to ask to you, how many connections a db server can handle. I know the question is not so easy, and actually I don't want to known a "number" but something like: - up to 100 ...

Stefano Nichele
Dec 12, 2008 at 10:07 am
Jan 12, 2009 at 10:08 am
2
Re: [ADMIN] rebellious pg stats collector (reopened case)

%cat test.c #include <stdio.h int main() { while(1) { sleep(5); printf("ppid = %d\n", getppid()); } } %gcc -o test test.c %./test ppid = 47653 ppid = 47653 ppid = 47653 # Started "truss -p 48864" ...

Laszlo Nagy
Dec 22, 2008 at 1:57 pm
Dec 22, 2008 at 2:00 pm
2
pg_restore : out of memory

Hi, I am trying to restore a table out of a dump, and I get an 'out of memory' error. The table I want to restore is 5GB big. Here is the exact message : [email protected]:/home/backup-sas$ pg_restore -F ...

Franck Routier
Dec 4, 2008 at 2:20 pm
Dec 19, 2008 at 8:00 am
2
filesystems benchmark

Hi I'm trying to compare different filesystems for postgres using pgbench. The problem I've seen is that my IO wait is very very low. Is there a way I can get pgbench to do more to push that up a ...

Adrian Moisey
Dec 15, 2008 at 6:56 am
Dec 15, 2008 at 6:09 pm
1
perform 1 check vs exception when unique_violation

I have to insert rows to table with 95% primary key unique_violation. I've tested 2 examples below: 1) BEGIN INSERT INTO main (name, created) VALUES (i_name, CURRENT_TIMESTAMP AT TIME ZONE 'GMT'); ...

Anton Bogdanovitch
Dec 30, 2008 at 10:55 am
Dec 30, 2008 at 2:51 pm
1
temp_tablespaces and RAID

Hello, To improve performances, I would like to try moving the temp_tablespaces locations outside of our RAID system. Is it a good practice ? Thanks, Marc Mamin

Marc Mamin
Dec 22, 2008 at 3:12 pm
Dec 22, 2008 at 6:07 pm
1
Fwd: Not so simple query and a half million loop

Hi, all! No one knows why I got "actual time=0.014..0.570 rows=30 loops=511222" and "actual time=0.005..0.006 rows=1 loops=15158976"? With: cu.cal_user_type = 'u' AND cu.cal_recur_date = ...

Daniel Cristian Cruz
Dec 2, 2008 at 4:02 pm
Dec 19, 2008 at 1:25 am
1
insert and Update slow after implementing slony.

Hi, We are trying to implement slony as a replication tool for one of our database. The Insert and updates have increased by approximately double making some of our important script slow. The ...

Nimesh Satam
Dec 17, 2008 at 4:03 am
Dec 17, 2008 at 8:01 pm
1
Degenerate Performance Problem

I have postgresql 8.3.5 installed on MacOS X / Darwin. I remember setting shared memory buffer parameters and that solved the initial performance problem, but after running several tests, the ...

Vincent Predoehl
Dec 10, 2008 at 3:33 am
Dec 10, 2008 at 3:47 am
1
Context switch storms

Hi there, We've recently started seeing some context switch storm issues on our primary Postgres database, and I was wondering if anyone had encountered similar issues or had any ideas as to what ...

Omar Kilani
Dec 2, 2008 at 8:51 am
Dec 5, 2008 at 10:42 pm
0
Query planner plus partitions equals very bad plans, again

Here is a query on a partitioned schema that produces a very bad query plan. The tables are fully vacuumed, analyzed with stats target 40, and no bloat (created with pure inserts, no updates or ...

Scott Carey
Dec 21, 2008 at 8:08 pm
Dec 21, 2008 at 8:08 pm