> On 13 Apr 2017, at 11:42, Kyotaro HORIGUCHI <horiguchi.kyot...@lab.ntt.co.jp> > wrote: > > At Thu, 13 Apr 2017 13:52:40 +0900, Michael Paquier > <michael.paqu...@gmail.com> wrote in > <CAB7nPqTRyica1d-zU+YckveFC876=sc847etmk7trgas2pa...@mail.gmail.com> >> On Tue, Apr 11, 2017 at 5:38 PM, Kyotaro HORIGUCHI >> <horiguchi.kyot...@lab.ntt.co.jp> wrote: >>> Sorry, what I have just sent was broken. >> >> You can use PROVE_TESTS when running make check to select a subset of >> tests you want to run. I use that all the time when working on patches >> dedicated to certain code paths. > > Thank you for the information. Removing unwanted test scripts > from t/ directories was annoyance. This makes me happy. > >>>> - Relation has new members no_pending_sync and pending_sync that >>>> works as instant cache of an entry in pendingSync hash. >>>> - Commit-time synchronizing is restored as Michael's patch. >>>> - If relfilenode is replaced, pending_sync for the old node is >>>> removed. Anyway this is ignored on abort and meaningless on >>>> commit. >>>> - TAP test is renamed to 012 since some new files have been added. >>>> >>>> Accessing pending sync hash occurred on every calling of >>>> HeapNeedsWAL() (per insertion/update/freeze of a tuple) if any of >>>> accessing relations has pending sync. Almost of them are >>>> eliminated as the result. >> >> Did you actually test this patch? One of the logs added makes the >> tests a long time to run: > > Maybe this patch requires make clean since it extends the > structure RelationData. (Perhaps I saw the same trouble.) > >> 2017-04-13 12:11:27.065 JST  t/102_vacuumdb_stages.pl >> STATEMENT: ANALYZE; >> 2017-04-13 12:12:25.766 JST  LOG: BufferNeedsWAL: pendingSyncs >> = 0x0, no_pending_sync = 0 >> >> - lsn = XLogInsert(RM_SMGR_ID, >> - XLOG_SMGR_TRUNCATE | XLR_SPECIAL_REL_UPDATE); >> + rel->no_pending_sync= false; >> + rel->pending_sync = pending; >> + } >> >> It seems to me that those flags and the pending_sync data should be >> kept in the context of backend process and not be part of the Relation >> data... > > I understand that the context of "backend process" means > storage.c local. I don't mind the context on which the data is, > but I found only there that can get rid of frequent hash > searching. For pending deletions, just appending to a list is > enough and costs almost nothing, on the other hand pendig syncs > are required to be referenced, sometimes very frequently. > >> +void >> +RecordPendingSync(Relation rel) >> I don't think that I agree that this should be part of relcache.c. The >> syncs are tracked should be tracked out of the relation context. > > Yeah.. It's in storage.c in the latest patch. (Sorry for the > duplicate name). I think it is a kind of bond between smgr and > relation. > >> Seeing how invasive this change is, I would also advocate for this >> patch as only being a HEAD-only change, not many people are >> complaining about this optimization of TRUNCATE missing when wal_level >> = minimal, and this needs a very careful review. > > Agreed. > >> Should I code something? Or Horiguchi-san, would you take care of it? >> The previous crash I saw has been taken care of, but it's been really >> some time since I looked at this patch... > > My point is hash-search on every tuple insertion should be evaded > even if it happens rearely. Once it was a bit apart from your > original patch, but in the latest patch the significant part > (pending-sync hash) is revived from the original one.
This patch has followed along since CF 2016-03, do we think we can reach a conclusion in this CF? It was marked as "Waiting on Author”, based on developments since in this thread, I’ve changed it back to “Needs Review” again. cheers ./daniel -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers