>> Le 08/01/2011 04:24, Tatsuo Ishii a écrit : >>>> On Fri, Jan 7, 2011 at 5:46 AM, Tatsuo Ishii <[email protected]> wrote: >>>>> >>>>> On master we do: >>>>> >>>>> BEGIN; >>>>> SELECT 1 FROM t1_i_seq FOR UPDATE; >>>> >>>> and why you are allowed to execute FOR UPDATE in a sequence? i mean, >>>> if you can't lock the secuence it has no sense that you can lock the >>>> rows on it... is it not a postgres bug that we should report instead >>>> of exploit it? >>> >>> Not sure I want to report it. >> >> In my opinion, *if* this is actually a bug, we must report it. It's all about >> code quality, sanity and fiability. > > I'm not against if you want to report it. > >>> The "bug" does not hurt PostgreSQL users >>> in any sense, for example security issues. >>> >>> Theoreticaly we could fix this "bug" and provide "formal" way to lock >>> sequences instead. But I doubt PostgreSQL cores agree to provide such >>> new API, which is probably only benefitical to pgpool users. >> >> *If* this is a bug, what if it just accept the lock, but doesn't respect it ? > > It does respect. I already tested it. > >>> So I guess reporting the "bug" and fixing it will not benefit anyone, >>> on the other hand pgpool users will lose their benefit. >> >> If we rely on a bug for a feature, then the design is probably somewhat >> broken no ? > > What we need is someway to lock a sequence. I'm sure this is an > important piece to implement query based replication which works with > sequences. > > If there's better way to do it, I'm happy to use it. Unfortunately > there's no alternative in the current PostgreSQL implementation.
BTW, if cores decide that is a bug and remove the "future" without providing alternative, we could do live with it by creating a dummy table to be locked. (Actualy I first tried to lock sequence table itself without success). This way is not convienient because we have to create such table before hand though. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp _______________________________________________ Pgpool-hackers mailing list [email protected] http://pgfoundry.org/mailman/listinfo/pgpool-hackers
