Large pgstat.stat file causes I/O storm

Hello all,

I have a ~150GB sized server, containing two databases that are active in
mostly read mode. I have noticed lately that the global/pgstat.stat file
is somewhere around 1MB freshly after a restart, but at some point it
baloons to 74MB in size for no apparent reason, after a few hours of
uptime. Needless to say, having the stats collector dump 74MB of stuff on
disk on its every loop takes a big bite of the I/O capabilities of this
box.

Looking at all the othe replicas I have of this database (but which are
under a more lightweight read load), the pgstat.stat file again is rather
small in size. Am I right to assume that a 74MB pgstat.stat file is not
normal - and what might have caused it?

Thanks,

Cristian
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Cristian Gafton
rPath, Inc.