Re: impacts of moving from informix 7.1 to 7.3 ?

Atiqullah Hashmi wrote: > > Hi, > > We are currently using informix 7.1 on solaris 2.5 and found that informix > 7.3 is soon to be released. Could someone point out major differences > or things that could impact if you are moving from 7.1. We don't have > complex database but the size of database is big(about 1 GB). We had > performance problems when we moved from informix 5.0 to 7.1 and so > we are a bit concerned about 7.3 upgrade. Not to worry. IDS 7.3 is already out on Solaris/SPARK (indeed 7.30UC2 is due out next week with some minor bug fixes). Reports from users already using 7.30UC1 are that 7.3 is 25% -> 55% faster than 7.2 which was slightly faster than 7.1x in general and noticable faster at I/O than 7.1x. There are new features all but one of which are optional and will improve performance. The only gotcha that I know about is the subquery unrolling feature. IDS 7.3 will recognize a correllated sub-query and understands that ALL such queries can be rewritten and executed as simple joins and so it will do just that, execute the statement as if it had been a join. The gotcha is that if you do not have an index on the join columns of the two tables then 7.3 may run slower than 7.2 did. The fix is simple, add the missing indexes and your queries will run MUCH faster under 7.3 than under 7.2. Several package vendors who use Informix are busy adding indexes to their databases so that their ill-advised sub-queries can take advantage of 7.3. Art S. Kagel