Thread: RE: Query is slow when run for first time; subsequent execution isfast
On windows, how to put an entry in my db startup script to run this query （pg_prewarm） immediately after startng the server, and let the query warm the cache itself.
After starting the server, I want to know what is the server, and it is the database I restarted or windows system?
Thank you.
>Hi,
>On 17 Jan 2018 12:55, "POUSSEL, Guillaume" <guillaume(dot)poussel(at)sogeti(dot)com>
>wrote:
>Are you on Windows or Linux? I’m on Windows and wondering if the issue is
>the same on Linux?
>I have experienced this on Mac and Linux machines.
>You can try pg_prewarm, on pg_statistic table and its index. But I'd
>probably just put an entry in my db startup script to run this query
>immediately after startng the server, and let the query warm the cache
>itself.
>I will try this suggestion and get back on the thread. Is pg_statistic the
>only table to be pre cached? Pls let me know if any other table/index needs
>to be pre warmed.
>
>
>Btw, I don't running a "select * from pg_statistic" will fill the shared
>buffer. Only 256 kb of data will be cached during sequential scans. I will
>try pg_prewarm
>
>
>Why do you restart your database often
>
>
>Postgres is bundled with our application and deployed by our client.
>Starting / stopping the server is not under my control.
>
>
>Regards,
>Nanda
On Tue, Sep 4, 2018 at 3:16 AM jimmy <mpokky@126.com> wrote:
On windows, how to put an entry in my db startup script to run this query （pg_prewarm） immediately after startng the server, and let the query warm the cache itself.
Starting with PostgreSQL version 11 (to be released soon), you can use pg_prewarm.autoprewarm.
Until then, maybe this: https://superuser.com/questions/502160/run-a-scheduled-task-after-a-windows-service-is-started
I've tested neither one.
Cheers,
Jeff