Re: Upgrade and Update Stats

Yes, it is necessary at a minimum. You also need to recompile all of your stored procedures and it is prudent to drop all distributions on all tables and recreate them all using dostats or the equivalent protocols. The last is not always needed, but from any one version of IDS to another the internal format of the data distributions changes. Unfortunately if the optimizer encounters any distributions records in an earlier format it will ignore all distributions for that table, so you have to get rid of all of the older distributions if the format has changed. The big problem is that the release notes never tell us which version hops will encounter a change in internal format, so to be safe I always drop all distributions (usually by just issuing a DELETE FROM sysdistrib; statement as informix) after an upgrade and just run dostats -d databasename with default options on every database in the server instance to kick start the new distributions and recompile all of the SPL routines. Since IDS 1..50 adds new low level stats to systables, syscolumns, sysindexes, and sysdistrib which are partly for the use of the new Auto Update Statistics feature, it's a good idea to go through the wholerigamoral no matter which version you are upgrading from. 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 Tue, May 12, 2009 at 6:41 AM, Habichtsberg, Reinhard < RHabichtsberg@arz-emmendingen.de> wrote: > > We are migrating "in-place" from IDS 9.40FC9W2 to IDS 11.50.FC3. The > databases we are migrating are all "up to stats" because we use Art's > dostats in a dayly rhythm. > > In the Migration Guide it is recommended to make an "update statistics > medium" on all not-leading index rows. With the databases we are migrating > it would last days if we did so. > > Is it really neccessary to follow that recommandation? > > Mit freundlichem Gruß > > Reinhard Habichtsberg > Datenbankadministration > *-203 > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >