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Re: [INTERFACES] Dealing with large query results

From: Hannu Krosing <hannu(at)trust(dot)ee>
To: Matthew Hagerty <matthew(at)venux(dot)net>
Cc: pgsql-interfaces(at)postgreSQL(dot)org
Subject: Re: [INTERFACES] Dealing with large query results
Date: 1999-02-08 21:25:32
Message-ID: 36BF564C.D1A9F8FA@trust.ee (view raw or flat)
Thread:
Lists: pgsql-interfaces
Matthew Hagerty wrote:
> 
> Greetings,
> 
> I keep seeing reference to an 8K limit on query results.  So how to deal
> with query results greater than 8K?  Am I under the wrong impression that
> when you run a query from, say libpq, that each retch row is returned only
> when you execute a fetchrow?  Or is the whole query stuffed in to a buffer
> which has an 8K limit?

the current 8K limit is for queries (and unrelatedly single rows), 
not query _results_
 
> I have to deal with some queries that create a huge result, and/or doing
> reports requires a large result set.  How can I deal with these larger results?

If you dont want to digest a huge result, you can do a 

DECLARE CURSOR - FETCH -FETCH - FETCH - CLOSE CURSOR thing to get it in
pieces

(needs to be inside BEGIN TRANSACTION - END TRANSACTION)
 
> I'll probably get flamed for asking this one but, how can I step through a
> table?  Hey, sometimes you just have to do it.

See above.

Actually postgres is quite happy to return gigabytes of data, if you
have 
the resources (disk space, memory, time ;)

--------------
Hannu

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