Re: Slow query through ODBC

Magnus Hagander a écrit :
> Since it works with different speeds in different clients, it *probably*
> isn't on the server side. I'm far from sure on that though, there may be
> other paramters that are implicitly changed when ODBC is used.

Yes, that was my first impression also. But the fact that the
server waits for an ACK from the client before it goes on sending
packet is quite strange, isn't it ?

> It's interesting to note that your problem is with a single large field.
> If you query for approximatly the same amount of data *but in several
> small fields*, do you get the same behaviour? Or does it happen only
> with large fields?

I have splitted the data into 4 fields.
The largest field was ~23.000 characters long, so I made 4 fields
containing. The first one contains the first 6000, the second one
from 6001 to 12000, etc...
The query took about half the time to run !

> We enable TCP_NODELAY on both server and client, when available. And it
> is available - I've double-checked and that code is indeed compiled into
> both libpq and the server on 8.1 at least.

I run 8.1.2, so I assume that it is enabled on my workstation and
on the server.

> But I don't see how this can make a difference between pgadmin and odbc
> and psql, since they all use the same code!

Yes, I really don't understand either !
But even though all use libpq.dll, they might not handle the data
the same way. Mayboe ODBC needs to check for data type, field
length, etc... and the other frontends do not need this kind of
information ?

Regards
--
Arnaud