From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, JanWieck(at)Yahoo(dot)com, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: PL/pgSQL bug? |
Date: | 2001-09-07 16:16:10 |
Message-ID: | 200109071616.f87GGBr07790@candle.pha.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
I am not sure if there is a TODO item here, but if there is, please let
me know. Thanks.
> > -----Original Message-----
> > From: Tom Lane
> >
> > I believe the reason for this is that in Read Committed mode,
> > each separate query from the client computes a new snapshot (see
> > SetQuerySnapshot calls in postgres.c). So, when your
> > "select ctid, i from t1" query executes, it computes a snapshot
> > that says T1 is committed, and then it doesn't see the row left
> > over from T1. On the other hand, your plpgsql function operates
> > inside a single client query and so it's using just one QuerySnaphot.
> >
> > One way to make the results equivalent is to compute a new QuerySnapshot
> > for each SPI query. Quite aside from the cost of doing so, I do not
> > think it makes sense, considering that the previous QuerySnapshot must
> > be restored when we return from the function. Do we really want
> > functions to see transaction status different from what's seen outside
> > the function call?
>
> Yes I do.
>
> > I doubt it.
> >
> > The other way to make the results the same is to omit the
> > SetQuerySnapshot calls for successive client-issued queries in one
> > transaction.
>
> What's different from SERIALIZABLE mode ?
>
> regards,
> Hiroshi Inoue
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo(at)postgresql(dot)org
>
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
From | Date | Subject | |
---|---|---|---|
Next Message | Patrick Welche | 2001-09-07 16:21:26 | Re: backend hba.c prob |
Previous Message | Bruce Momjian | 2001-09-07 16:12:19 | Re: [COMMITTERS] pgsql/src/backend/utils/mb encnames.c |