Update statistics on 7.11 Online
OS: UNIX System V/386/486 Release 4.0 Version 3.
Platform: Single Processor NCR
Software: Informix Online 7.11UC2
Does anyone know of a bug with update statistics?
Here is my problem:
Table XYZ is 240,000 pages in size (124,477 data, 49,959 index,
62,534 free and 30 in Bit map pages). Table is an highly updated
table and update stat occurs only once a week for this table.
Yet when I issue the following:
update statistics medium for table XYZ;PROBLEM ------> It is taking over 10 hours to complete
update statistics high for table XYZ;PROBLEM " It is taking over 8 hours to complete.
What I have noticed:
Using the SMI sysptprof table that it gets to a certain point and
then starts to do a lot of buffer waits!!!!! By the completion it has
done over 515,818,452 buffer reads and has only 59,234 pagreads
(page reads) with NO seqscan (sequential scans)
During the early processing and prior to the start of accumulating
the massive amount of buffer reads the pagreads is increasing by 3 to
4 thousand pages per min. Once it starts accumulating buffer waits
(as seen via onstat -p (bufwaits), the pagereads is only increasing
by 10 to 20 pages per min.
What I have tried/done:
1. oncheck -cDI shows no problems with the table.
2. Increasing the number of buffers, went to the max and got down
to 2 hours (yet, this is the only thing executing, attempt anything
else and my system TIES UP).
In general my ONCONFIG looks good via all performance specifications
that I have reviewed (Sutto, this list and Informix Manuals of course).
So does ANYONE have an IDEA of what the problem could be OR if there is
an Informix BUG that I just do not know about. Feel free to e-mail me
directly if you have any idea.
Thanks in advance!
Cheryl L. Kendricks
Informix DBA: vnibs2@heb.com