AW: drop distributions

Hi Jack controlling the btree cleaner with onstat -C you could see one cleaner working on one table all the time with type leaf. Informix support suggested to start more cleaners with type range. onmode -C rangesize 500 onmode -C threshold 50000 onmode -C stop onmode -C stop onmode -C start onmode -C start My impression is that some long checkpoint which where waiting on threads in critical section disappeared. Why do you assume that it has influence on the optimizer? Regards, Reinhard. > -----Ursprüngliche Nachricht----- > Von: informix-list-bounces@iiug.org > [mailto:informix-list-bounces@iiug.org]Im Auftrag von Jack Parker > Gesendet am: Dienstag, 18. März 2008 13:37 > An: Habichtsberg, Reinhard; Informix-List (E-Mail) > Betreff: RE: drop distributions > > Problem may be btree cleaner threads, not the drop distributions. > > j. > > Sane ego te vocavi. Forsitan capedictum tuum desit. > > -----Original Message----- > From: informix-list-bounces@iiug.org > [mailto:informix-list-bounces@iiug.org]On Behalf Of Habichtsberg, > Reinhard > Sent: Tuesday, March 18, 2008 2:07 AM > To: Informix-List (E-Mail) > Subject: drop distributions > > > Hi. > > After upgrading from IDS 9.40.FC4W2 to 9.40.FC9W2 some > queries run extremly > slow and I'm under the impression that the optimizer chooses > the wrong way > especially when OPTCOMPIND is 1 or 2. > > My idea is to drop distributions. The problem is "update > statistics low on > table xxx drop distributions" runs very, very long on large > tables. So, is > it safe, to delete the rows for the table in the sysdistrib > table? Update > statistics low could be run anyway. The advantage is that it > would cost no > time to test the optimizer without distributions. > > BTW: We have an OLTP and Decison Support mixed environment > with very large > tables. What do you think is the best value for OPTCOMPIND in > onconfig. In > 9.40 is not possible to "set OPTCOMPIND" with the session and we have > applications that cannot set an environment variable. > > And is there any advantage of distributions if I set OPTCOMPIND to 0? > > Thanks in advance for your help. > > Reinhard. > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >