RE: Question on Extent Size

KalpanaPai wrote > > We are running informix 9.21 on Solaris, the page size is 2k . The db > was setup by prev DBA, as i am new to Informix (from oracle) I have > few queries on extent size. > > We have around 100 tables , every table has created with default > extent size (16k and next 16k). > > Some of the tables are showing extent size like > > table1: 1208787 next ext 120878 > table2: 2472 next 247 > 56723 next 5672 etc, > Some small tables shows still 16k and next extent 16 , > > But when i run the query to find the no of extents for each table > still they show les than 8 extetns some of them even 1 or 2 extents. > > 1. Is above extents size are ok or will it affect any queries? > 2. Do they have to be dropped and recreated? > 3. The tables with what extent size needs to be recreated? > 3. If i need to recreate , what is the first and next extent size i > should give? > > Any suggestions, guidelines highly appreciated. It is ideal if the data for a table is kept in one coninuous block (unless you are deliberatly using fragmentation) so the extent size should try and maximise this. For fast growing tables you need large next extent sizes, for static tables 10% should suffice. You could get some benefit by dropping table 1 and creating it again with much larger extents. With very large tables I would try and make it a multiple of the maximum pages in a chunk. extent size 1048000 next size 1048000 would be my suggestion Colin Bull sending to informix-list