On Mon, Feb 5, 2024 at 10:00 AM Hayato Kuroda (Fujitsu) <kuroda.hay...@fujitsu.com> wrote: > > > > > Amit, this has been applied as of 861f86beea1c, and I got pinged about > > the fact this triggers inconsistencies because we always set the LSN > > of the write buffer (wbuf in _hash_freeovflpage) but > > XLogRegisterBuffer() would *not* be called when the two following > > conditions happen: > > - When xlrec.ntups <= 0. > > - When !xlrec.is_prim_bucket_same_wrt && !xlrec.is_prev_bucket_same_wrt > > > > And it seems to me that there is still a bug here: there should be no > > point in setting the LSN on the write buffer if we don't register it > > in WAL at all, no? > > Thanks for pointing out, I agreed your saying. PSA the patch for diagnosing > the > issue. >
@@ -692,6 +697,9 @@ _hash_freeovflpage(Relation rel, Buffer bucketbuf, Buffer ovflbuf, if (!xlrec.is_prev_bucket_same_wrt) wbuf_flags |= REGBUF_NO_CHANGE; XLogRegisterBuffer(1, wbuf, wbuf_flags); + + /* Track the registration status for later use */ + wbuf_registered = true; } XLogRegisterBuffer(2, ovflbuf, REGBUF_STANDARD); @@ -719,7 +727,12 @@ _hash_freeovflpage(Relation rel, Buffer bucketbuf, Buffer ovflbuf, recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_SQUEEZE_PAGE); - PageSetLSN(BufferGetPage(wbuf), recptr); + /* Set LSN to wbuf page buffer only when it is being registered */ + if (wbuf_registered) + PageSetLSN(BufferGetPage(wbuf), recptr); Why set LSN when the page is not modified (say when we use the flag REGBUF_NO_CHANGE)? I think you need to use a flag mod_wbuf and set it in appropriate places during register buffer calls. -- With Regards, Amit Kapila.