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Re: Re: onstat -g ppf - lkrqrs X isrd X bfrd

Posted By: jack.parker4@verizon.net
Date: Wednesday, 23 February 2011, at 11:45 a.m.

In Response To: Re: onstat -g ppf - lkrqrs X isrd X bfrd (Cesar Inacio Martins)

You might also check into the sysmaster DB, there you can find the page reads/ page writes for each dataspace (including indices). Might be easier to script.

Something like:
#Write more than read
select c.tabname, a.indexname, c.pagreads, c.pagwrites
from sysfragments a, sysmaster:sysptprof c
where a.indexname is not null

and a.partn=c.partnum

and pagwrites > pagreads

j.

Feb 23, 2011 04:16:20 PM, ids@iiug.org wrote:

===========================================

The reason of this isrd x bfrd is because the statistics was zeroed a few days
ago (onstat -z), so probally the pages of this indexes already buffered since
then...

Well, some of this indexes have the same value of bfwrt and bfrd...

Thanks Jack for your suggestion.

anyone else?

--- Em qua, 23/2/11, jack.parker4@verizon.net
escreveu:

De: jack.parker4@verizon.net
Assunto: Re: onstat -g ppf - lkrqrs X isrd X bfrd [22868]
Para: ids@iiug.org
Data: Quarta-feira, 23 de Fevereiro de 2011, 12:55

Consider that a write requires a read. Looking for 0 reads could be
misleading. Look for indexes where the number of reads is equivalent to the
number of writes.

j.

Feb 23, 2011 02:58:57 PM, ids@iiug.org wrote:

===========================================

Hi,

I'm trying to identify useless indexes on the database. (v10 and v11)

For this I'm using the 'onstat -g ppf' where I have filtered indexes partnum
what the isrd equal to 0 (isam read) .

With this, I deduce, any SQL use this index for access the table since the
statistics was zeroed (onstat -z). But I can see somes bfrd and lkrqrs with
values on some indexes...

I supose this two columns have values because occur updates/deletes into the
table where affect the ROWID or the field of the index and for this the engine
need to lock, read and update this indexes (but this not occur via "isam read"
because is some internal process of the engine)

This is correct?

Cesar

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Messages In This Thread

• onstat -g ppf - lkrqrs X isrd X bfrd
  Cesar Inacio Martins -- Wednesday, 23 February 2011, at 9:58 a.m.
  • Re: onstat -g ppf - lkrqrs X isrd X bfrd
    jack.parker4@verizon.net -- Wednesday, 23 February 2011, at 10:55 a.m.
    • Re: onstat -g ppf - lkrqrs X isrd X bfrd
      Cesar Inacio Martins -- Wednesday, 23 February 2011, at 11:15 a.m.
      • Re: Re: onstat -g ppf - lkrqrs X isrd X bfrd
        jack.parker4@verizon.net -- Wednesday, 23 February 2011, at 11:45 a.m.

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