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Thread: RE: [INTERFACES] invalid lo descriptorc in begin commit fraze

RE: [INTERFACES] invalid lo descriptorc in begin commit fraze

From
Peter Mount
Date:
I'll look into it. There shouldn't be anything in the driver to limit
the number of concurrent objects.

Does anyone else see this type of problem (I'm thinking of those who use
libpq rather than JDBC)?

Peter

-- 
Peter Mount
Enterprise Support
Maidstone Borough Council
Any views stated are my own, and not those of Maidstone Borough Council.


-----Original Message-----
From: M.Mazurek@poznan.multinet.pl [mailto:M.Mazurek@poznan.multinet.pl]
Sent: Tuesday, February 15, 2000 5:12 PM
To: pgsql-interfaces@postgreSQL.org
Subject: [INTERFACES] invalid lo descriptorc in begin commit fraze


Hi,
I have a servlet which some lo (images) from postgres and ouputs them to
the web page. If I start only one instatnce of that servlet - no
problem. When there are serveral servlets reading lo - 
FastPath call returned ERROR:  lo_read: invalid large obj descriptor (1)
I have db.AutoCommit(false) at opening the connection, and
db.commit() after reading data.
How to read serveral lo, even the same one in the same time from various
servlets avoiding that error?
linux2.0.13, jserv1.1, postgresql6.3.5, jsdk2.0, jdk1.2.2

thx
mazek


************

Re: [INTERFACES] invalid lo descriptorc in begin commit fraze

From
Tom Lane
Date:
Peter Mount <petermount@it.maidstone.gov.uk> writes:
> I'll look into it. There shouldn't be anything in the driver to limit
> the number of concurrent objects.
> Does anyone else see this type of problem (I'm thinking of those who use
> libpq rather than JDBC)?

I got the impression that what he was talking about was multiple
independent threads issuing commands across a single backend connection.
When one thread commits its transaction, all the others lose their open
LO descriptors.  I don't see any way to fix that short of changing the
client code so that each thread is talking to a different backend.

If I'm all wrong about this, I'll crawl back in my hole now...
        regards, tom lane

Re: [INTERFACES] invalid lo descriptorc in begin commit fraze

From
M.Mazurek@poznan.multinet.pl
Date:
On Wed, 16 Feb 2000, Tom Lane wrote:

> I got the impression that what he was talking about was multiple
> independent threads issuing commands across a single backend connection.
NO, evry servlet starts his own connection. Is not to be very occupied
site, so I allowed my self for such a simplicity:).
It's enough to have three starting servlets, and lo_read error is
generated.
mazek


Marcin Mazurek

-- 
administrator
MULTINET SA o/Poznan
http://www.multinet.pl/