Tool to estimate the size of an index
A user on IDS 11.50.FC4 (AIX 6.1) wanted a tool to estimate index size from key length and row count, having found that his Excel sheet based on the Performance Guide's "Estimating Conventional index pages" method differed significantly from actual index sizes. Art Kagel supplied the rough formula used by myschema: ((keylen + 4) * 1.5) * numrows, noting it ignores index tree depth, FILLFACTOR, and page splitting/condensing over time. The poster then uploaded his spreadsheet to the IIUG Software Repository.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
Hi all I need a tool to estimate the size of an index based on key size and number of records. Does anyone know of any? Thank you very much
Sorry, I forgot to provide the version of the installation: IBM Informix Dynamic Server Version 11.50.FC4 Operative System: AIX Version 6.1
bc? :-) Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. 2010/12/8 JOSé LUIS CABRERA SACCO <jcabrera@anda.com.uy> > Hi all > I need a tool to estimate the size of an index based on key size and number > of > records. Does anyone know of any? > Thank you very much > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --000e0cd14ed8becf4a0496ebcc79
Actually I have an Excel spreadsheet made based on the "Performance Guide (Estimating Conventional index pages)", but comparing the value obtained in the form with the real size of the index created, I have important differences! My intention was to estimate the size of the index with any other tool that was more accurate than my return! I apologize for my English. All this text is generated using the google translator! Anyway, thank you very much for responding! :-))) Greetings
I was in an odd mood the other day, my comment was unnecessary. The formula that myschema uses is: ((keylen + 4) * 1.5) * numrows That's an estimate, and does not take into account the depth of the index tree and does not allow for different FILLFACTORs or the splitting and condensing of pages over time once the index goes into service. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. 2010/12/9 JOSé LUIS CABRERA SACCO <jcabrera@anda.com.uy> > Actually I have an Excel spreadsheet made based on the "Performance Guide > (Estimating Conventional index pages)", but comparing the value obtained in > the form with the real size of the index created, I have important > differences! > My intention was to estimate the size of the index with any other tool that > was more accurate than my return! > > I apologize for my English. All this text is generated using the google > translator! > > Anyway, thank you very much for responding! :-))) > > Greetings > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001636c5a28cce90550496fb3b14
Don't worry. Anyone can have a bad day. Furthermore, it was my fault too because I was not too clear, exposing the problem (because of my poor command of English). Thank you very much for the formula. If you want, I can send you the spreadsheet I made for the validity and offer it to other users. I hope this google translator is good and you can understand what I say! Really, thank you very much!
The translation is clear enough and certainly better than the reverse translations I've seen from English to French, Spanish, or Portuguese when I've needed them. My French is good enough to know the output is very rough and awkward. The community would certainly appreciate your posting the spreadsheet to the IIUG Software Repository for all to use. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. 2010/12/9 JOSé LUIS CABRERA SACCO <jcabrera@anda.com.uy> > Don't worry. Anyone can have a bad day. Furthermore, it was my fault too > because I was not too clear, exposing the problem (because of my poor > command > of English). > > Thank you very much for the formula. > > If you want, I can send you the spreadsheet I made for the validity and > offer > it to other users. > > I hope this google translator is good and you can understand what I say! > > Really, thank you very much! > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --00504502e485ebd3e70496fd76ee
OK. I did the upload in the IIUG Software Repository. I hope someone finds it useful. Bye