Re: Strange checkpoint behavior - checkpoints take a long time

Hi,

On 2017-10-05 22:58:31 +0300, Vladimir Nicolici wrote:
> I changed some configuration parameters during the night to the values I was considering yesterday:
>
> - shared_buffers = 144GB #previously 96 GB
> - bgwriter_lru_maxpages = 100 #previously 400
> - checkpoint_timeout = 30min #previously 5min
> - checkpoint_completion_target = 0.83 #previously 0.85; 0.83 means 25 minutes writes out of 30 minutes.
> - max_wal_size = 96GB #previously 16GB

Which version of postgres is this?

> - wal_buffers = 16MB #previously 32 MB

That seems quite unlikely to help.

You might want to try also enabling wal_compression, sometimes the WAL
volume is a considerable problem.

I'd suggest reporting some "pidstat -dl 1" output, so we can see which
processes are doing how much IO.

Regards,

Andres