Re: After ~Crash Sequence not correct - Mailing list pgsql-bugs

From Henshall, Stuart - WCP
Subject Re: After ~Crash Sequence not correct
Date
Msg-id E2870D8CE1CCD311BAF50008C71EDE8E01F7475F@MAIL_EXCHANGE
Whole thread Raw
In response to After ~Crash Sequence not correct  ("Henshall, Stuart - WCP" <SHenshall@westcountrypublications.co.uk>)
List pgsql-bugs
No. I had fsync on.
- Stuart

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: 19 December 2001 18:49
To: Mikheev, Vadim
Cc: Henshall, Stuart - WCP; pgsql-bugs@postgreSQL.org
Subject: Re: [BUGS] After ~Crash Sequence not correct


"Mikheev, Vadim" <vmikheev@SECTORBASE.COM> writes:
> It was made to avoid WAL-loging on each nextval call, ie it should work
> like OID pre-fetching: value stored in WAL must always "exceed" values
> returned by nextval so on the after-crash-restart sequence should be
> advanced to value which was never returned by nextval (for non-cycled
> sequences). Maybe I made some mistakes in implementation?

Oh, okay.  What I saw was that the next nextval() after restart was
higher than what I was expecting; but that's correct given the prefetch
behavior.

But we've seen several reports wherein the value appeared to go
backwards after a crash.

Stuart, you weren't running with -F (fsync off) by any chance, were you?

            regards, tom lane

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