[GENERAL] Write performance on a large database

2011-06-09 Thread Håvard Wahl Kongsgård
Hi, I have performance issues on very large database(100GB). Reading from
the database is no problem, but writing(or heavy writing) is a nightmare.
I have tried tuning postgresql, but that does not seem to improving the
writing performance.
To improve the write performance, what are my options?


-- 
Håvard Wahl Kongsgård

http://havard.security-review.net/


Re: [GENERAL] Write performance on a large database

2011-06-09 Thread Vick Khera
2011/6/9 Håvard Wahl Kongsgård haavard.kongsga...@gmail.com:
 To improve the write performance, what are my options?

add more ram. add more checkpoint segments. get faster disks.  reduce
the number of indexes you have. split your big tables into smaller
partitions.

which of these may work depends on your exact problem.  we don't know
what that is.

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Re: [GENERAL] Write performance on a large database

2011-06-09 Thread tv
 Hi, I have performance issues on very large database(100GB). Reading from
 the database is no problem, but writing(or heavy writing) is a nightmare.
 I have tried tuning postgresql, but that does not seem to improving the
 writing performance.
 To improve the write performance, what are my options?

Hard to tell with this little info. We need to know more about your
hardware (CPU, RAM, disk setup, ...), PostgreSQL configuration (number of
checkpoint segments, ...) and output from tools like vmstat and iostat.

regards
Tomas


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Re: [GENERAL] Write performance on a large database

2011-06-09 Thread Alan Hodgson
On June 9, 2011 05:15:26 AM Håvard Wahl Kongsgård wrote:
 Hi, I have performance issues on very large database(100GB). Reading from
 the database is no problem, but writing(or heavy writing) is a nightmare.
 I have tried tuning postgresql, but that does not seem to improving the
 writing performance.
 To improve the write performance, what are my options?

Buy fast disks (many), attach them to a good raid controller with a battery-
backed write cache, setup in RAID-10. Or move to SSD.

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Re: [GENERAL] Write performance on a large database

2011-06-09 Thread Greg Smith

On 06/09/2011 08:15 AM, Håvard Wahl Kongsgård wrote:
Hi, I have performance issues on very large database(100GB). Reading 
from the database is no problem, but writing(or heavy writing) is a 
nightmare.
I have tried tuning postgresql, but that does not seem to improving 
the writing performance.

To improve the write performance, what are my options?


Well, technically you have performances issues on a medium sized 
database.  The simplest answer to your question is buy a server with 
96GB of RAM.  If it's still possible to get a server that holds your 
entire database in memory for a moderate investment, it's really not 
large yet.


There are many free guides that discuss various aspects of write 
performance and tuning around them, some of which are excerpts from my 
book which goes over all of this territory:


http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server : Covers 
general server tuning
http://www.westnet.com/~gsmith/content/postgresql/chkp-bgw-83.htm : 
Discusses the exact way checkpoints work and how people commonly tune them
http://wiki.postgresql.org/wiki/Reliable_Writes : all four of the 
references there cover this area.
http://projects.2ndquadrant.com/talks : The Write Stuff presentation 
goes over some of the limitations people run into with high write volume 
applications.


I'd suggest taking a look at those.  If you want to talk more about this 
afterwards, start a new discussion on the pgsql-performance list with 
some of the information recommended at 
http://wiki.postgresql.org/wiki/SlowQueryQuestions :  disk controller 
and disk info, PostgreSQL version, and database server configuration all 
have a lot of impact here.  The contents of pg_stat_bgwriter would be 
interesting too.


--
Greg Smith   2ndQuadrant USg...@2ndquadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us
PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books


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