On Thu, Nov 14, 2013 at 7:58 AM, Jayadevan <maymala.jayade...@gmail.com>wrote:
> Jeff Janes wrote > > No. The checkpointer writes all data that was dirty as of a certain time > > (the start of the checkpoint) regardless of how often it was used since > > dirtied, and the background writer writes data that hasn't been used > > recently, regardless of when it was first dirtied. Neither knows or > cares > > whether the data being written was committed, rolled back, or still in > > progress. > > Thank you. So checkpointer writes "all dirty data" while backgrounder > writes > "all or some dirty data" depending on some (Clocksweep?) algorithm. > Correct? > From this discussion > > http://postgresql.1045698.n5.nabble.com/Separating-bgwriter-and-checkpointer-td4808791.html > < > http://postgresql.1045698.n5.nabble.com/Separating-bgwriter-and-checkpointer-td4808791.html > > > the bgwrites has some 'other dutties'. Probably those involve marking the > buffers - when they were last used, how frequently etc? > > > > That should have been "backgrounder writes "all or some dirty or non-dirty data" "...
