From: Robert Haas <robertmh...@gmail.com> > Were the issues that I mentioned regarding GIST (and maybe other AMs) > in the last paragraph of > http://postgr.es/m/CA+TgmoZEZ5RONS49C7mEpjhjndqMQtVrz_LCQUkpRW > dmrev...@mail.gmail.com > addressed in some way? That seems like a pretty hard engineering > problem to me, and I don't see that there's been any discussion of it. > Those are correctness concerns separate from any wal_level tracking we > might want to do to avoid accidental mistakes.
Thank you very much for reminding me of this. I forgot I replied as follows: -------------------------------------------------- Unlogged GiST indexes use fake LSNs that are instance-wide. Unlogged temporary GiST indexes use backend-local sequence values. Other unlogged and temporary relations don't set LSNs on pages. So, I think it's enough to call GetFakeLSNForUnloggedRel() when wal_level = none as well. -------------------------------------------------- But this is not correct. We have to allow (RM_GIST_ID, XLOG_GIST_ASSIGN_LSN) WAL records to be emitted (by tweaking the filter in XLogInsert()), just like those WAL records are emitted when wal_level = minimal and and other WAL records are not emitted. Regards Takayuki Tsunakawa
