Re: Performance issue

Posted in 1997

Bill Ennis — 28 Apr 1997 13:08:31 -0400 — source: Informix-list mailing list archive (1991-1998)

> > We are using Informix 7.2 > > Two questions, I hope anyone know something about it: > > 1) Does select max(colname) generate a full scan if colname is the > primary key? It shouldn't, but the only way to be sure is to SET EXPLAIN ON and read the access path used by the optimizer in sqexplain.out. > > 2) Does the order of the search criteras in a where clause inflict > the performance? (where a=1 and b='aaa' and c=2) > No - not at least with any recent versions of the engine. This used to matter in very old versions (prior to version 4). -- Bill Ennis Voice: 312-474-7516 SSA Fax: 312-474-7460 500 W. Madison email: ennis@ssax.com ennis@accesschicago.net