Re: BYTEA Fields and Memory Consumption

From: Ramesh Reddy <rareddy(at)redhat(dot)com>
To: Hiroshi Inoue <inoue(at)tpf(dot)co(dot)jp>
Cc: Raiford(at)labware(dot)com, pgsql-odbc(at)postgresql(dot)org
Subject: Re: BYTEA Fields and Memory Consumption
Date: 2011-04-14 23:48:21
Message-ID: 1302824901.3497.26.camel@localhost.localdomain
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In my experience even when using 'lo' the driver only got the first
chunk of data which is equal to the length of the buffer that client
provided and never went back to ask for next chunk.

Also, I am not sure how one can read multiple blocks from client code?

Ramesh..

On Fri, 2011-04-15 at 08:42 +0900, Hiroshi Inoue wrote:
> (2011/04/14 21:17), Raiford(at)labware(dot)com wrote:
> > Hi Hiroshi-san,
> >
> > Thank you for your response. Could you clarify one thing for me? Are you
> > suggesting that when using an lo datatype with the lo module installed,
>
> You don't have to install the lo module. Please type
>
> create domain lo as oid;
>
> and use the lo type.
>
> > the ODBC driver automatically sends the data in pieces?
>
> Yes.
>
> regards,
> Hiroshi Inoue
>
> > Or does it only
> > open the possibility for me to use the lo_import() function? If
> > everything is handled internally in the ODBC driver, it would certainly
> > help a lot :)
> >
> > Jon
> >
> > From: Hiroshi Inoue <inoue(at)tpf(dot)co(dot)jp>
> > To: Raiford(at)labware(dot)com
> > Cc: pgsql-odbc(at)postgresql(dot)org
> > Date: 04/13/2011 11:42 PM
> > Subject: Re: [ODBC] BYTEA Fields and Memory Consumption
> > Sent by: pgsql-odbc-owner(at)postgresql(dot)org
> > ------------------------------------------------------------------------
> >
> > Hi,
> >
> > (2011/04/13 21:09), Raiford(at)labware(dot)com wrote:
> > > I have an issue where even though I break a large BYTEA object up into
> > > multiple pieces, the ODBC driver just rejoins the pieces in memory and
> > > tries to send it all out at once. I took a look at the code and sure
> > > enough the driver just keeps reallocating memory for each chunk of data
> > > that I add.
> >
> > Yes you are right.
> >
> > > Can I assume Postgres has no mechanism to send this data
> > > across the wire in pieces? Are there any common practices for dealing
> > > with this?
> >
> > Please try lo type instead of bytea type.
> >
> > regards,
> > Hiroshi Inoue
>

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