| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Reinhard Hnat <hnat(at)logotronic(dot)co(dot)at> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: How long does commit take? |
| Date: | 2007-04-26 14:52:07 |
| Message-ID: | 23569.1177599127@sss.pgh.pa.us |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-novice |
Reinhard Hnat <hnat(at)logotronic(dot)co(dot)at> writes:
> I would like to know how long it will take until the effects of a
> transaction is visible from outside after a commit statement.
There is no delay.
> Or in
> other words: I have the situation that i have to use data which is
> inserted within a transaction immediately after the transactions is
> committed, but sometimes the new data is not available a this moment (A
> few moments later it is available). Is there any method to check if data
> is ready to be used before 'selecting' it?
I think you may be confused by the MVCC mechanism. A SQL statement will
absolutely see everything that is committed as of the instant of the
"snapshot" it's using. I think what you are describing is probably the
effect of having taken a snapshot just before the commit occurred. See
http://www.postgresql.org/docs/8.2/static/mvcc.html
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Daniel T. Staal | 2007-04-26 15:16:43 | Re: How long does commit take? |
| Previous Message | Francois Deliege | 2007-04-26 13:24:43 | Re: moving data from windows to linux |