On 02/26/2012 01:11 PM, Stefan Keller wrote:
2012/2/26 Andy Colson<andy@xxxxxxxxxxxxxxx> wrote:
On 02/25/2012 06:16 PM, Stefan Keller wrote:
1. How can I warm up or re-populate shared buffers of Postgres?
2. Are there any hints on how to tell Postgres to read in all table
contents into memory?
Yours, Stefan
How about after you load the data, vacuum freeze it, then do something like:
SELECT count(*) FROM osm_point WHERE tags @> 'tourism=>junk'
-Andy
That good idea is what I proposed elsewhere on one of the PG lists and
got told that this does'nt help.
I can accept this approach that users should'nt directly interfere
with the optimizer. But I think it's still worth to discuss a
configuration option (per table) or so which tells PG that this table
contents should fit into memory so that it tries to load a table into
memory and keeps it there. This option probably only makes sense in
combination with unlogged tables.
Yours, Stefan
I don't buy that. Did you test it? Who/where did you hear this? And... how long does it take after you replace the entire table until things are good and cached? One or two queries?
After a complete reload of the data, do you vacuum freeze it?
After a complete reload of the data, how long until its fast?
-Andy
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