| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | pgsql-performance(at)postgresql(dot)org |
| Cc: | Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, darcy(at)wavefire(dot)com, jd(at)www(dot)commandprompt(dot)com, sfrost(at)snowman(dot)net, herve(at)elma(dot)fr |
| Subject: | Re: PostgreSQL clustering VS MySQL clustering |
| Date: | 2005-01-23 22:42:52 |
| Message-ID: | 200501231442.52830.josh@agliodbs.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Tatsuo,
> I'm not clear what "pgPool only needs to monitor "update switching" by
>
> *connection* not by *table*" means. In your example:
> > (1) 00:00 User A updates "My Profile"
> > (2) 00:01 "My Profile" UPDATE finishes executing.
> > (3) 00:02 User A sees "My Profile" re-displayed
> > (6) 00:04 "My Profile":UserA cascades to the last Slave server
>
> I think (2) and (3) are on different connections, thus pgpool cannot
> judge if SELECT in (3) should go only to the master or not.
>
> To solve the problem you need to make pgpool understand "web sessions"
> not "database connections" and it seems impossible for pgpool to
> understand "sessions".
Depends on your connection pooling software, I suppose. Most connection
pooling software only returns connections to the pool after a user has been
inactive for some period ... generally more than 3 seconds. So connection
continuity could be trusted.
--
Josh Berkus
Aglio Database Solutions
San Francisco
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Hannu Krosing | 2005-01-23 23:28:29 | Re: PostgreSQL clustering VS MySQL clustering |
| Previous Message | Tom Lane | 2005-01-23 22:39:12 | Re: Odd number of rows expected |