Re: Protocol 3, Execute, maxrows to return, impact? - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: Protocol 3, Execute, maxrows to return, impact?
Date
Msg-id 87vdzdbov3.fsf@oxford.xeocode.com
Whole thread Raw
In response to Re: Protocol 3, Execute, maxrows to return, impact?  (Abhijit Menon-Sen <ams@oryx.com>)
Responses Re: Protocol 3, Execute, maxrows to return, impact?  ("Stephen R. van den Berg" <srb@cuci.nl>)
List pgsql-hackers
"Abhijit Menon-Sen" <ams@oryx.com> writes:

>> Interleaved retrieval using multiple portals is not what most
>> libraries support, I'd guess.
>
> My code did support that mode of operation in theory, but in practice
> in the few situations where I have needed to use something like it, I
> found it more convenient to open explicit cursors and FETCH from them

Note that using FETCH for each record means a round trip to the server for
each record. If you're dealing with a lot of records that could be a lot
slower than streaming them to the client as quickly as it can consume them.

Now I'm not sure anyone's actually done any experiments to optimize libpq or
other drivers to stream data efficiently, so I'm not sure how much you would
really lose in practice today.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production
Tuning


pgsql-hackers by date:

Previous
From: Abhijit Menon-Sen
Date:
Subject: Re: WITH RECURSIVE updated to CVS TIP
Next
From: Josh Berkus
Date:
Subject: Re: CommitFest: how does handoff work for non-committer reviewers?