From: <gnuoytr@rcn.com>
Subject: Re: Postgres refusing to use >1
 core
To: sthomas@peak6.com, "Scott Marlowe" <scott.marlowe@gmail.com>
Cc: "Craig Ringer" <craig@postnewspapers.com.au>,
	"Aren Cambre" <aren@arencambre.com>, pgsql-performance@postgresql.org
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Date: Wed, 11 May 2011 15:53:09 -0400 (EDT)

---- Original message ----
>Date: Wed, 11 May 2011 11:04:49 -0500
>From: pgsql-performance-owner@postgresql.org (on behalf of Shaun Thomas <sthomas@peak6.com>)
>Subject: Re: [PERFORM] Postgres refusing to use >1 core  
>To: Scott Marlowe <scott.marlowe@gmail.com>
>Cc: Craig Ringer <craig@postnewspapers.com.au>,Aren Cambre <aren@arencambre.com>,<pgsql-performance@postgresql.org>
>
>On 05/10/2011 11:26 PM, Scott Marlowe wrote:
>
>> I.e. don't grab 1,000 rows and work on them on the client side and
>> then insert data, do the data mangling in the query in the database.
>> My experience has been that moving things like this into the database
>> can result in performance gains of several factors, taking hour long
>> processes and making them run in minutes.
>
>This is a problem I encounter constantly wherever I go. Programmer 
>selects millions of rows from giant table. Programmer loops through 
>results one by one doing some magic on them. Programmer submits queries 
>back to the database. Even in batches, that's going to take ages.
>
>Databases are beasts at set-based operations. If the programmer can 
>build a temp table of any kind and load that, they can turn their 
>update/insert/whatever into a simple JOIN that runs several orders of 
>magnitude faster. Going the route of parallelism will probably work too, 
>but I doubt it's the right solution in this case.
>
>When there are tables with millions of rows involved, processing 111 per 
>second is a bug. Even with ten perfectly balanced threads, 30 hours only 
>becomes three. On decent hardware, you can probably drop, reload, and 
>index the entire table faster than that.
>
>-- 
>Shaun Thomas
>OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
>312-676-8870
>sthomas@peak6.com
>
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So, the $64 question:  how did you find an engagement where, to bend Shakespeare, "first thing we do, is kill all the coders" isn't required?  This RBAR mentality, abetted by xml/NoSql/xBase, is utterly pervasive.  They absolutely refuse to learn anything different from the COBOL/VSAM messes of their grandfathers; well modulo syntax, of course.  The mere suggestion, in my experience, that doing things faster with fewer lines of code/statements in the engine is met with overt hostility.

Regards,
Robert