Re: [GENERAL] shared_buffers smaller than max_wal_size

On 09/24/2017 11:03 AM, Vladimir Mihailenco wrote:
> Thanks for your response. Ss I understand it now the difference is
> that checkpoints are synchronous but dirty pages eviction from shared
> buffers are asynchronous, correct? How then Postgres ensures that OS
> writes data to the disk so WAL can be deleted?
> 

The last step in a checkpoin is fsync() on the files. Without that, the
checkpoint is considered incomplete and the database won't rely on it.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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