Обсуждение: caching complete table for optimizing search ?

Hello,

I'm running a search query on a table with approximately 120.000 rows
(3848 relpages, dbsize tablesize 30MB).

Because of poor performance I would like to cache the complete table in
memory, but I'm not sure which config param I have to use to accomplish
that.
The other tables in the db are rather small.

What configuration values are best for this kind of database ?

Postgres 8.0beta2 on a
RedHat-Linux with
Pentium Celeron 1500
256MB RAM


Thx
berger

I'm not sure what to do to cache a single table, but we use a tool called memcached to accomplish what you are describing. Memcached will cache the db in RAM, allowing you to do all of your reads from memory. Writes are  more expensive, because you have to write to the db and to the cache, but if you have a db that it mostly getting selected against, and performance is a concern, this might be a good solution. You can get more info about memcached at: http://www.danga.com/memcached/.

Heather Johnson
Senior Database Programmer
New York Post

-----Original Message-----
From: pgsql-admin-owner@postgresql.org
To: pgsql-admin@postgresql.org
Sent: 10/27/2004 12:57 PM
Subject: [ADMIN] caching complete table for optimizing search ?

Hello,

I'm running a search query on a table with approximately 120.000 rows
(3848 relpages, dbsize tablesize 30MB).

Because of poor performance I would like to cache the complete table in
memory, but I'm not sure which config param I have to use to accomplish
that.
The other tables in the db are rather small.

What configuration values are best for this kind of database ?

Postgres 8.0beta2 on a
RedHat-Linux with
Pentium Celeron 1500
256MB RAM


Thx
berger


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> Hello,
>
> I'm running a search query on a table with
> approximately 120.000 rows
> (3848 relpages, dbsize tablesize 30MB).
>
> Because of poor performance I would like to cache
> the complete table in memory, but I'm not sure which
> config param I have
> to use to accomplish
> that.
> The other tables in the db are rather small.

Maybe a redesign of the query is a better idea.
What about creating indexes?

If you provide info about the tables and the query
maybe we can help you.

Your table is very small (just 120.000 rows) but think
about cache a table of millions of rows thats not
optimus.


>
> What configuration values are best for this kind of
> database ?
>
> Postgres 8.0beta2 on a
> RedHat-Linux with
> Pentium Celeron 1500
> 256MB RAM
>

There are some docs talking about modifiyng the
postgresql.conf, but i said info about your database,
your tables and data is needed.


Maybe the PERFORMANCE list is more adecuate.
>
> Thx
> berger
>
>

you welcome.


regards,
Jaime Casanova

_________________________________________________________
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I'm not sure what to do to cache a single table, but we use a tool called memcached to accomplish what you are describing. Memcached will cache the db in RAM, allowing you to do all of your reads from memory. Writes are  more expensive, because you have to write to the db and to the cache, but if you have a db that it mostly getting selected against, and performance is a concern, this might be a good solution. You can get more info about memcached at: http://www.danga.com/memcached/.

Heather Johnson
Senior Database Programmer
New York Post

-----Original Message-----
From: pgsql-admin-owner@postgresql.org
To: pgsql-admin@postgresql.org
Sent: 10/27/2004 12:57 PM
Subject: [ADMIN] caching complete table for optimizing search ?

Hello,

I'm running a search query on a table with approximately 120.000 rows
(3848 relpages, dbsize tablesize 30MB).

Because of poor performance I would like to cache the complete table in
memory, but I'm not sure which config param I have to use to accomplish
that.
The other tables in the db are rather small.

What configuration values are best for this kind of database ?

Postgres 8.0beta2 on a
RedHat-Linux with
Pentium Celeron 1500
256MB RAM


Thx
berger


---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
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