RE: Checking indexes after large deletes
Posted in 2006
"Onstat -g btc" must be a V10 feature, I don't have it available on my
V9.4 instance.
-----Original Message-----
From: informix-list-bounces@iiug.org
[mailto:informix-list-bounces@iiug.org] On Behalf Of Art S. Kagel
Sent: Tuesday, June 06, 2006 3:16 PM
To: informix-list@iiug.org
Subject: Re: Checking indexes after large deletes
bozon wrote:
> Good idea to drop the index first. In general this is what I do, but
> this process is part of a job that removes customer data for
> customers that no longer use our product. It is part of a monthly
> cleanup and it happens while the instance is on line.
>
> So is there a way to know if the cleaner is keeping up and
> restructuring the indexes (by removing the keys that are marked
> deleted and then reorganizing the nodes to rebalance the B-Tree?
onstat -g btc
Will show you what index pages have been marked for cleaning. If you
see a preponderence of pages for a single partnum (index or index
fragment) that would be a candidate for a rebuild if you cannot wait for
the Btree Cleaners to catch up.
Art S. Kagel
> Marco Greco wrote:
>
>>bozon wrote:
>>
>>>Is there a way to determine how "messed up" an index is after a large
>>>number of deletes have been done to a table? I searched here and
>>>didn't see anything. Is there an oncheck command or sysmaster table
>>>to look at? If so what values should I look for? I have to make a
>>>case for rebuilding indexes and having hard data would make my case
stronger.
>>>
>>>Thanks.
>>>
>>>_______________________________________________
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>>>Informix-list@iiug.org
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>>>
>>
>>Why rebuild the index after you have gone through the effort of
>>marking all those keys as deleted? drop the index first.
>>Caveat: if you are using the index to drive the delete, that might not
>>be a good idea...
>>
>>--
>>Ciao,
>>Marco
>>______________________________________________________________________
________
>>Marco Greco /UK /IBM Standard
disclaimers apply!
>>
>>Structured Query Scripting Language
http://www.4glworks.com/sqsl.htm
>>4glworks
http://www.4glworks.com
>>Informix on Linux
http://www.4glworks.com/ifmxlinux.htm
>
>
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