Re: An impossible thing to guess, but...

><Nils.Myklebust@nmdata.com> wrote: > >On Thu, 2 Jul 1998 15:12:44 -0400, "Narkinsky, Pat" ><Pat.Narkinsky@rivhs.com> wrote: > >> >>I have an Informix 7.14UD7 database running a vertical application. >> >>The vendor of this application has told me that, in order to fix some >>significant performance problems we have been having, I need to: >>1) Upgrade Informix from 7.14UD7 to 7.24.UC5 >>2) Rebuild the database by dropping it (using dbexport) and then >>importing it (using dbimport). > >There may be a direct upgrade path from one to the other so you don't >have to do dbexport/dbimport. Check that with your local Informix >office. Nils is right, there is a direct upgrade path. I have recently had to upgrade databases running under 7.14.UD1, 7.10.UC2, and 7.10.UC3 to 7.23.UC6. In each case, I stopped the existing instance. After installing the new executables to a new $INFORMIXDIR, then modifying the ONCONFIG to include any new entries and remove obsolete ones, re-starting the instance led to message log entries like: ... 11:26:07 Dataskip is now OFF for all dbspaces 11:26:07 On-Line Mode 11:26:07 Converting 'sysmaster' database ... 11:26:08 Checkpoint Completed: duration was 1 seconds. 11:27:07 'sysmaster' database built successfully. 11:31:12 Checkpoint Completed: duration was 2 seconds. Of coure, I made sure that I had two good backups prior to attempting these conversions, and I took another backup afterward, so that I wouldn't have to re-convert if the database crashed. I have heard that there can be some problems restoring a database from an archive created by an older release (probably because of the differences in the sysmaster database). Your vendor may still want you to do the dbexport/dbimport to clean up any extent interleaving though, and that's probably a good idea, depending on how many extents the tables have. I would tend to agree with Nils that the best way to guesstimate the duration would be to run a dbexport, then maybe multiply that by maybe 3 or 4 to get the total time for the dbexport/dbimport, because the dbimport will have to build all of your indexes. This assumes that you can get the system to yourself, since dbexport places an exclusive lock on the database. Mark Collins mcollins@us.dhl.com Dilbert is a documentary.