I notice that the metric maxwritten_clean in the table pg_stat_bgwriter increases (for example going from 0 to 1000 in several seconds). I guess this is understandable as it happens while there are some spikes of writes in the database. According to the documentation, this behavior is driven by the parameter bgwriter_lru_maxpages but I can't find any recommendations/best practices on how to set this parameter.

Therefore, I've several questions:

  1. Is it bad to see this counter increasing?
  2. Do you have any ratio to share to have some kind of alerting on it?
  3. Is it a good idea to update the parameter bgwriter_lru_maxpages in order to reduce the number of occurrences of maxwritten_clean?

Thanks a lot for your help,


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