Re: Performance degraded with grouping and sorting.

Play the video

Subject: Re: Performance degraded with grouping and sorting.
From: Geert Josten <Geert.Josten@xxxxxxxxxxx>
Date: Sat, 30 Oct 2004 12:16:35 +0200

Oh wait, why not predict the performance myself..

In the original code the grouping algorithm starts with picking the first of each ACCT_NBR:

<xsl:for-each select="PROJECTION[count(. | key('group-by-accountnbr', ACCT_NBR)[1]) = 1]">

Well, that is a *very* expensive operation. The index is accessed for _each_ PROJECTION elements, so
about 2000 times! And if each distinct ACCT_NBR 'contains' about 10 PROJECTIONs, 9 out of 10 times
the predicate gives the same result. Very inefficient... :-(

Unfortunatily, I can't think of any other way of determining the first of a group other than
variations on this theme or performing sorting in a previous step and using the index on first items
I suggested.

Anyone good ideas?

Grtz,
Geert

Current Thread

RE: Performance degraded with grouping and sorting., (continued)
- Kielen, Agnes - Fri, 29 Oct 2004 08:37:32 +0200
  - Geert Josten - Sat, 30 Oct 2004 11:50:19 +0200
    - Geert Josten - Sat, 30 Oct 2004 12:16:35 +0200 <=
    - Michael Kay - Sat, 30 Oct 2004 12:54:58 +0100
    - Geert Josten - Sat, 30 Oct 2004 17:43:26 +0200
    - Michael Kay - Sat, 30 Oct 2004 17:50:31 +0100
    - Colin Paul Adams - 30 Oct 2004 18:30:26 +0100

<- Previous	Index	Next ->
Re: Performance degraded with, Geert Josten	Thread	RE: Performance degraded with, Michael Kay
Re: Performance degraded with, Geert Josten	Date	Re: Dynamic processing of xml, Michael
	Month

PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Subscribe in XML format

RSS 2.0
Atom 0.3

XML Editor - Download a 15 Day Free Trial Now >

See What's New in Stylus Studio >

Buy Stylus Studio - XML Editor - Now >