> On 2 May 2018 at 13:10, Michael Paquier <michael@paquier.xyz> wrote:
> On Wed, May 02, 2018 at 12:22:34PM +0200, Dmitry Dolgov wrote:
>> Recently I've heard people complaining that Postgres doesn't expose any
>> statistics about how many full page writes happened during some time
>> frame.
>
> pg_waldump --stats?
Yep, pg_waldump is the only option so far, but I thought about something that
will directly expose this info.
> The bar to add new fields into pgstat structures is usually quite high
> depending on the location where those are added. For example not so
> long ago there was a patch discussed about adding more fields to
> PgStat_StatTabEntry, which has been rejected as pgstat can be a problem
> for users with many tables. See here:
> https://www.postgresql.org/message-id/1323.1511624064%40sss.pgh.pa.us
>
> Your patch adds a new field to PgStat_StatDBEntry? Wouldn't you
> increase the bottleneck of deployments with many databases? What's
> actually your use case?
This was discussed mostly in the context of benchmarking and understanding IO
for different workloads. I actually never realized that adding a new stats
field can have significant impact in those cases when there are too many
databases, and yeah, I'm afraid it may be not justified in this context.
