Re: Threaded Sorting - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Threaded Sorting
Date
Msg-id 200210041726.g94HQiV24901@candle.pha.pa.us
Whole thread Raw
In response to Threaded Sorting  (Hans-Jürgen Schönig <postgres@cybertec.at>)
Responses Re: Threaded Sorting  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Threaded Sorting  (Greg Copeland <greg@CopelandConsulting.Net>)
List pgsql-hackers
Hans-J�rgen Sch�nig wrote:
> Threads are bad - I know ...
> I like the idea of a pool of processes instead of threads - from my 
> point of view this would be useful.
> 
> I am planning to run some tests (GEQO, AIX, sorts) as soon as I have 
> time to do so (still too much work ahead before :( ...).
> If I had time I'd love to do something for the PostgreSQL community :(.
> 
> As far as sorting is concerned: It would be fine if it was possible to 
> define an alternative location for temporary sort files using SET.
> If you had multiple disks this would help in the case of concurrent 
> sorts because this way people could insert and index many tables at once 
> without having to access just one storage system.
> This would be an easy way out of the IO limitation ... - at least for 
> some problems.

Bingo!  Want to increase sorting performance, give it more I/O
bandwidth, and it will take 1/100th of the time to do threading.

Ingres had a nice feature where you could specify sort directories and
it would cycle through those directories while it did the tape sort.

Added to TODO:
* Allow sorting to use multiple work directories

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


pgsql-hackers by date:

Previous
From: Bruce Momjian
Date:
Subject: Re: Potential Large Performance Gain in WAL synching
Next
From: Bruce Momjian
Date:
Subject: Re: Threaded Sorting