table Extent

Hi All, I run oncheck -pt command & found that in few of the tables we have more 15 extents, moreover I have found that in one table we have 211 and some them having 35+ extents. Is tables with too many extents can have a negative impact on Informix response times since data is scattered in many different parts of the disk. Please help me, what any action required on this?

Hi DJ, Please, let me know operational system, version of OS and IDS... How bg is the table with 211 extents ? How large is your instance? If you have window to do it, unload the rows of the table and recreate a table with greater first extent and next extent. Or, move a table in a new dbspace, create a dbspace and use the statement: alter fragment on table <tablename> init in <new_dbspace>. Pay attention with log and locks .... BR R Ferronato > To: ids@iiug.org > From: djoshih@hotmail.com > Subject: table Extent [18084] > Date: Thu, 12 Nov 2009 11:25:14 -0500 > > Hi All, > > I run oncheck -pt command & found that in few of the tables we have more 15 > extents, moreover I have found that in one table we have 211 and some them > having 35+ extents. > > Is tables with too many extents can have a negative impact on Informix > response times since data is scattered in many different parts of the disk. > > Please help me, what any action required on this? > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > _________________________________________________________________ Windows Live: Friends get your Flickr, Yelp, and Digg updates when they e-mail you. http://www.microsoft.com/middleeast/windows/windowslive/see-it-in-action/social- network-basics.aspx?ocid=PID23461::T:WLMTAGL:ON:WL:en-xm:SI_SB_3:092010

Your tables with 200+ extents have to be reorganized because they are approaching the maximum number of extents that a table can have. Other than that one worry, multiple extents has little effect on performance due to how IDS caches the extent information itself and the table's data pages. There is some negative effect when the count gets high, but 35 extents isn't usually a problem. Art Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Thu, Nov 12, 2009 at 10:25 AM, DEEPAK JOSHI <djoshih@hotmail.com> wrote: > Hi All, > > I run oncheck -pt command & found that in few of the tables we have more 15 > extents, moreover I have found that in one table we have 211 and some them > having 35+ extents. > > Is tables with too many extents can have a negative impact on Informix > response times since data is scattered in many different parts of the disk. > > Please help me, what any action required on this? > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --0015174794286466a804782f291c

I think this guy is on version 7.13 - I am not sure that the extent caching ferschnizzles were in that version... MM

Extent caching was introduced in 6.01. 5.xx only cached 8 extents at a time per table, but since 6 we're good. Art Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Thu, Nov 12, 2009 at 10:48 AM, MIKE MAGIE <jmmagie@yahoo.com> wrote: > I think this guy is on version 7.13 - I am not sure that the extent caching > ferschnizzles were in that version... > > MM > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --00151747609acca67d04782f6797