On Wed, Dec 7, 2016 at 2:49 PM, Kyotaro HORIGUCHI <horiguchi.kyot...@lab.ntt.co.jp> wrote: > Aside from measurement of the two sorting methods, I'd like to > point out that quorum commit basically doesn't need > sorting. Counting conforming santdbys while scanning the > walsender(receiver) LSN list comparing with the target LSN is > O(n). Small refactoring of SyncRerpGetOldestSyncRecPtr would > enough to do that.
Indeed, I haven't thought about that, and that's a no-brainer. That would remove the need to allocate and sort each array, what is simply needed is to track the number of times a newest value has been found. So what this processing would do is updating the write/flush/apply values for the first k loops if the new value is *older* than the current one, where k is the quorum number, and between k+1 and N the value gets updated only if the value compared is newer. No need to take the mutex lock for a long time as well. By the way, the patch now conflicts on HEAD, it needs a refresh. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
