Re: New statistics for tuning WAL buffer size

Hi, thanks for useful comments.

>> I agree to expose the number of WAL write caused by full of WAL
>> buffers.
>> It's helpful when tuning wal_buffers size. Haribabu separated that
>> number
>> into two fields in his patch; one is the number of WAL write by
>> backend,
>> and another is by background processes and workers. But I'm not sure
>> how useful such separation is. I'm ok with just one field for that
>> number.
> I agree with you. I don't think we need to separate the numbers for
> foreground processes and background ones. WAL buffer is a single
> resource. So "Writes due to full WAL buffer are happening. We may be
> able to boost performance by increasing wal_buffers" would be enough.

I made a patch to expose the number of WAL write caused by full of WAL
buffers.
I'm going to submit this patch to commitfests.

As Fujii-san and Tsunakawa-san said, it expose the total number
since I agreed that we don't need to separate the numbers for
foreground processes and background ones.

By the way, do we need to add another metrics related to WAL?
For example, is the total number of WAL writes to the buffers useful to
calculate the dirty WAL write ratio?

Is it enough as a first step?

Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION