On Mon, 2006-05-01 at 18:20, Federico Campoli wrote:
> Hi.
>
> Yesterday I've migrated a PHPBB mysql database on a fresh install of
> postgresql 8.1.3 on a debian gnu/linux sarge 3.1.
>
> The python script that migrate schema and data worked fine and I got
> all data on the my postgresql database.
>
> But, when the number of phpbb connected users increase (about 70-80),
> postgresql go crazy.
>
> The number of postgres process increase too and not decrease when the
> php pages released the connection (I use not persistent connection on
> my php cofiguration).
This actually usually points to a problem in your web server with
crashing processes leaving postgresql children up not disconnecting
properly.
A quick fix is to set a REALLY low tcp_keepalive in the networking on
those machines, assuming you're using tcp/ip sockets to connect. not
sure how to recover broken connections on local unix sockets.
> Changing the database parameter like checkpoint_timeout, write_mode
> and shared_buffer has no effect on this strange situation.
>
> I've noticed also that when the connected user increase after 70 the
> data are not commited immediately.
This is likely because those broken connections I mentioned above are
standing in the way of the actual, live connections.
Run top on the machine while this is happening and look for zombie
processes and such. Note that the most common cause of a crashing
apache is having modules compile against one set of libs and apache
compile against another.
How was your php server built? what version php is it, all that kind of
stuff might help us figure this out.