Re: Semantics of PostgreSQL Server Log Stats

Camilo Porto wrote:
>
> Hello,
>
> I would like to better understand the semantics of the statistics shown in PostgreSQL Logs. For example, in the report:
>
> DETAIL: ! system usage stats:
> ! 0.000100 elapsed 0.000000 user 0.000000 system sec
> ! [0.016997 user 0.006998 sys total]
> ! 0/0 [0/0] filesystem blocks in/out
> ! 0/2 [0/1301] page faults/reclaims, 0 [0] swaps
> ! 0 [0] signals rcvd, 0/0 [0/0] messages rcvd/sent
> ! 0/0 [6/20] voluntary/involuntary context switches

The above are from getrusage(). See the getrusage manual page.

> ! buffer usage stats:
> ! Shared blocks: 1 read, 0 written, buffer hit rate = 0.00%
> ! Local blocks: 0 read, 0 written, buffer hit rate = 0.00%
> ! Direct blocks: 0 read, 0 written
>
> What each element of this report mean?

This outlines the shared/local buffer I/O and file system I/O performed.

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