statistics on system catalog tables

Hi, I want to migrate one instance informix from 11.50 FC8 to 11.70 FC8W1. In the section "Completing required post-migration tasks" of thge Migration Guide, says: Update statistics on some system catalog tables after migrating After migrating successfully to Informix Version 11.70, run UPDATE STATISTICS on some of the system catalog tables in your databases. If you are migration from a Version 7.31 or 7.24 database server or moving data from that version to the current version, be sure to run UPDATE STATISTICS on the following system catalog tables in Informix Version 11.70: sysblobs system catalog table syscolauth system catalog table syscolumns system catalog table sysconstraints system catalog table sysdefaults system catalog table sysdistrib system catalog table sysfragauth system catalog table sysfragments system catalog table sysindices system catalog table sysobjstate system catalog table sysopclstr system catalog table sysprocauth system catalog table sysproceduressysroleauth system catalog table syssynonyms system catalog table syssyntable system catalog table systabauth system catalog table systables system catalog table systriggers system catalog table sysusers system catalog table My questions are: I need to run statistics if I migrate from 11.50 to 11.70? What is the purpose of running statistics to system catalog tables ? Thanks in advance, Roger

When you upgrade a version the internal format of the data distributions may change, so it is strongly recommended to drop all distributions and recreate them in the new version and that includes the distributions on the catalog tables. The engine and your applications query the catalog tables all the time, so good distributions on the catalog tables are a very good idea. You can use dostats to do all this for you: dostats -s mydatabase -m --drop-distributions The -m includes catalog tables and the --drop-distributions does what it says it does. Art Art S. Kagel, President and Principal Consultant ASK Database Management www.askdbmgt.com Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on 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. On Wed, Jul 22, 2015 at 5:03 PM, ROGER VILCA <rvilca@luzdelsur.com.pe> wrote: > Hi, > > I want to migrate one instance informix from 11.50 FC8 to 11.70 FC8W1. > In the section "Completing required post-migration tasks" of thge Migration > Guide, says: > > Update statistics on some system catalog tables after migrating> > After migrating successfully to Informix Version 11.70, run UPDATE > STATISTICS > on some of the system catalog tables in your databases. > If you are migration from a Version 7.31 or 7.24 database server or moving > data from that version to the current version, be sure to run UPDATE > STATISTICS on the following system catalog tables in Informix Version > 11.70: > > sysblobs system catalog table > syscolauth system catalog table > syscolumns system catalog table > sysconstraints system catalog table > sysdefaults system catalog table > sysdistrib system catalog table > sysfragauth system catalog table > sysfragments system catalog table > sysindices system catalog table > sysobjstate system catalog table > sysopclstr system catalog table > sysprocauth system catalog table > sysproceduressysroleauth system catalog table > syssynonyms system catalog table > syssyntable system catalog table > systabauth system catalog table > systables system catalog table > systriggers system catalog table > sysusers system catalog table > > My questions are: > > I need to run statistics if I migrate from 11.50 to 11.70? > What is the purpose of running statistics to system catalog tables ? > > Thanks in advance, > Roger > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001a113df88e72fc7d051b7e372d