RE: Fragmentation Strategy

Posted in 2004

Savio Pinto (s) — Fri, 28 May 2004 03:31:13 -0500 — source: Usenet: comp.databases.informix

This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C4448E.23207FD6 Content-Type: text/plain; charset="iso-8859-1" It really depends on what your query/application does. there are many factors, and depending on how you use the table fragmentation the query performance may degrade/improve by changing the fragmentation strategy/expression.......in order to use the informix table fragmentation the optimal way, you may need to analyze the queries used in the application, and then decide on which column you need to fragment the table or what fragmentation strategy is really needed for the table.... the way we used to do in a DSS env (batch process) is, fragment the table (mostly expression) across as many dbspaces as possible, and then use the values of the expression in the query and run multiple queries in parallel (same query but with different ranges, with the ranges coinciding with the table expression values on which it is fragmented), by doing this we used to get fragment elimination and excellent performance, whenever i used to do this, i never created an index on the table (but used PDQ).......informix fragmentation is very powerful .....if you use it the right way, you can do miracles with it. -----Original Message----- From: owner-informix-list@iiug.org [mailto:owner-informix-list@iiug.org]On Behalf Of Dirk Moolman Sent: Friday, May 28, 2004 1:57 AM To: informix-list@iiug.org Subject: Fragmentation Strategy I work for a company that works with medical aid claims from members. We currently use Solaris 9, and IDS 7.31FD3 (64bit) Our claims table is fragmented over 24 fragments (indexes are detached in their own fragments) Question: will a change in fragmentation strategy - fragmenting on a different column/s, help in increasing the performance, or is it basically dependant on the activity / usage of each fragment, or the number of fragments I have available, and not really the expression I fragment on ? Hope you understand the question! TIA Dirk _____ << ella for Spam Control >> has removed 1247 Spam messages and set aside 593 Newsletters for me You can use it too - and it's FREE! www.ellaforspam.com <http://www.ellaforspam.com>; ------_=_NextPart_001_01C4448E.23207FD6 Content-Type: text/html; charset="iso-8859-1" <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META content="MSHTML 5.50.4731.2200" name=GENERATOR> <STYLE>@page Section1 {size: 8.5in 11.0in; margin: 1.0in 77.95pt 1.0in 77.95pt; } P.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } LI.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } DIV.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } A:link { COLOR: blue; TEXT-DECORATION: underline } SPAN.MsoHyperlink { COLOR: blue; TEXT-DECORATION: underline } A:visited { COLOR: purple; TEXT-DECORATION: underline } SPAN.MsoHyperlinkFollowed { COLOR: purple; TEXT-DECORATION: underline } P.MsoPlainText { FONT-SIZE: 10pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Courier New" } LI.MsoPlainText { FONT-SIZE: 10pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Courier New" } DIV.MsoPlainText { FONT-SIZE: 10pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Courier New" } DIV.Section1 { page: Section1 } </STYLE> </HEAD> <BODY lang=EN-US vLink=purple link=blue> <DIV>It really depends on what your query/application does. there are many factors, and depending on how you use the table fragmentation the query performance may degrade/improve by changing the fragmentation strategy/expression.......in order to use the informix table fragmentation the optimal way, you may need to analyze the queries used in the application, and then decide on which column you need to fragment the table or what fragmentation strategy is really needed for the table....</DIV> <DIV> </DIV> <DIV>the way we used to do in a DSS env (batch process) is, fragment the table (mostly expression) across as many dbspaces as possible, and then use the values of the expression in the query and run multiple queries in parallel (same query but with different ranges, with the ranges coinciding with the table expression values on which it is fragmented), by doing this we used to get fragment elimination and excellent performance, whenever i used to do this, i never created an index on the table (but used PDQ).......informix fragmentation is very powerful .....if you use it the right way, you can do miracles with it.</DIV> <BLOCKQUOTE> <DIV class=OutlookMessageHeader dir=ltr align=left>-----Original Message----- From: owner-informix-list@iiug.org [mailto:owner-informix-list@iiug.org]On Behalf Of Dirk Moolman Sent: Friday, May 28, 2004 1:57 AM To: informix-list@iiug.org Subject: Fragmentation Strategy </DIV> <DIV class=Section1> I work for a company that works with medical aid claims from members. We currently use Solaris 9, and IDS 7.31FD3 (64bit)     Our claims table is fragmented over 24 fragments (indexes are detached in their own fragments)     Question:  will a change in fragmentation strategy - fragmenting on a different column/s, help in increasing the performance, or is it basically dependant on the activity / usage of each fragment, or the number of fragments I have available, and not really the expression I fragment on ?@@NL

RE: Fragmentation Strategy

Related threads

Your privacy choices