Le 19/09/2018 à 05:29, Thomas Munro a écrit :
> On Wed, Sep 19, 2018 at 1:35 PM jimmy <mpokky@126.com> wrote:
>> I use select pg_prewarm('table1','read','main') to load data of table1 into the memory.
>> when I use select count(1) from table1 group by aa to query data.
>> I find the speed of query is not fast, I wonder whether it query data from memory.
>> And it is slower than Oracle, both of Oracle and Postgresql has same table and count of data.
>> when pg_prewarm use 'read' mode, the data is put into the OS cache, how to examine the table which is pg_prewarmed
intothe OS cache .
>> I know pg_buffercache ,but it just examine the table in the shared buffer of Postgresql, not the table in the OS
cache.
>
> This is a quick and dirty hack, but it might do what you want:
>
> https://github.com/macdice/pgdata_mincore
>
> Tested on FreeBSD, not sure how well it'll travel.
You can use pgfincore extension for that purpose, and more.
https://github.com/klando/pgfincore/blob/master/README.md
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