Re: Database size different on Primary and Standby?

On 1/18/23 17:09, Hilbert, Karin wrote:
> I manage some PostgreSQL clusters on Linux.  We have a Primary & two
> Standby servers & for Production, there is also a DR server.  We use
> repmgr for our HA solution & the Standbys are cloned from the Primary
> using the *repmgr standby clone* command.
>
> My manager asked for a report of all the user databases & their sizes for
> each server in the cluster.
> I used the psql *"\l+"* command & then extracted the database name & the
> size from the output.
> I expected the databases to be the same size on the Standbys as on the
> Primary, but I found that some of the databases were smaller on the
> Standby servers than on the Primary.
>
> For example, the output on the Primary for one of the user databases
> showed as: *8997 kB*,but on the Standbys, it was *8849 kB*.
>
> I even dropped the database on the Primary & then restored it from a
> backup.  Then checked the sizes again & they still showed the difference.
>
> I also found that the template1 database on the Primary was *7821 kB*, but
> on the Standbys, it was *7673 kB*.
> */Is this normal?  Why would the sizes be different?/*

Maybe it is.  8997 - 8849 = 7821 - 7673 = 148.  That's right: both primaries
are exatly 148KB larger.

This will tell you where the differences are: $ du -kc $PGDATA

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Born in Arizona, moved to Babylonia.