On Tue, Mar 28, 2017 at 08:04:34AM +0530, Pavan Deolasee wrote: > And I've answered it so many times by now :-)
LOL > Just to add more to what I just said in another email, note that HOT/WARM > chains are created when a new root line pointer is created in the heap (a line > pointer that has an index pointing to it). And a new root line pointer is > created when a non-HOT/non-WARM update is performed. As soon as you do a > non-HOT/non-WARM update, the next update can again be a WARM update even when > everything fits in a single block. > > That's why for a workload which doesn't do HOT updates and where not all index > keys are updated, you'll find every alternate update to a row to be a WARM > update, even when there is no chain conversion. That itself can save lots of > index bloat, reduce IO on the index and WAL. > > Let me know if its still not clear and I can draw some diagrams to explain it. Ah, yes, that does help to explain the 50% because 50% of updates are now HOT/WARM. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
