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Re: JDBC causing the connection to close after executing a COPY command

From: Altaf Malik <mmalik_altaf(at)yahoo(dot)com>
To: Kris Jurka <books(at)ejurka(dot)com>
Cc: Dave Cramer <pg(at)fastcrypt(dot)com>, pgsql-jdbc(at)postgresql(dot)org
Subject: Re: JDBC causing the connection to close after executing a COPY command
Date: 2007-12-14 11:11:22
Message-ID: 577968.78807.qm@web39108.mail.mud.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
Yes i'll take care of that and send another patch.

Regards,
Altaf Malik
EnterpriseDB
http://www.enterprisedb.com/

Kris Jurka <books(at)ejurka(dot)com> wrote: 

On Thu, 13 Dec 2007, Altaf Malik wrote:

> I debugged little more and found that this is not because of incomplete 
> copy support. When a response to any of the copy operations is received, 
> JDBC reads next few bytes to ignore the response. But unfortunately 
> driver reads extra four bytes which is the RFQ message so the RFQ 
> message gets corrupted and IOException is thrown considering it as an 
> unknown packet.

Good catch.

> I am attaching a patch that fixes this issue and driver works smoothly 
> even after giving the error on copy response.
>

Sort of.  In the case of copying data from the server, if you do have a 
large table, you'll generate a SQLException for every row of the copy 
result which isn't great, but I guess it's better than failing completely. 
Trying to copy out a single column table of 100k integers took about seven 
minutes and 150 MB of memory here.

Also, it doesn't work for copying data to the server.  In that case the 
server is sitting waiting for data and the driver is waiting for the 
server and nothing happens.  That was the case before, so this is no 
worse.

Do you have plans to work on this further or shall I apply just this minor 
improvement?

Kris Jurka


       
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