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bdhobbs18@acm.org
 
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Default reorganizing indexes - 04-24-2009 , 06:13 PM






How does one determine if an index is in need of reorganizing? How
does one reorganize an index?

The information provided by rmu/analyze/indexes does not seem to
include the amount of fragmentation. Am I overlooking something?

Thank you

Rdb 7.0-61
VMS 7.1
emulated VAX 4000-105a
It would be great to upgrade, but those that hold the purse strings
don't want to upgrade. sigh


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Italiano
 
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Default Re: reorganizing indexes - 04-25-2009 , 05:31 AM






In the rare occasion that I have rebuild index was because the min/max
path to reach node's leaf or data row was very different.
Check documentation on RMU/ANALYZE/PLACEMENT, from there you can see
the I/O needed to reach node's leaf and data row.
Wich problem are you facing? Rdb do not have needs to do "RE-ORG" or
"RE-DO" commands.

Quote:
... amount of fragmentation...
Infact Rdb do not have this problem unless you are speaking about
"record fragmentation" ("record chain"? using Oracle vocabulary)

ciao
GIo

On Apr 25, 1:13*am, bdhobb... (AT) acm (DOT) org wrote:
Quote:
How does one determine if an index is in need of reorganizing? *How
does one reorganize an index?

The information provided by rmu/analyze/indexes does not seem to
include the amount of fragmentation. *Am I overlooking something?

Thank you

Rdb 7.0-61
VMS 7.1
emulated VAX 4000-105a
It would be great to upgrade, but those that hold the purse strings
don't want to upgrade. *sigh


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bdhobbs18@acm.org
 
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Default Re: reorganizing indexes - 04-27-2009 , 01:02 PM



On Apr 25, 3:31*am, Italiano <gio... (AT) gmail (DOT) com> wrote:
Quote:
In the rare occasion that I have rebuild index was because the min/max
path to reach node's leaf or data row was very different.
Check documentation on RMU/ANALYZE/PLACEMENT, from there you can see
the I/O needed to reach node's leaf and data row.
Wich problem are you facing? Rdb do not have needs to do "RE-ORG" or
"RE-DO" commands.

... amount of fragmentation...

Infact Rdb do not have this problem unless you are speaking about
"record fragmentation" ("record chain"? using Oracle vocabulary)
I don't have a problem with indexes or Rdb. I wasn't sure if I needed
to reorganize the indexes myself or if Rdb takes care of it. If I
understand your reply, Rdb reorganizes the indexes as needed.

Many many winters ago, I had to occasionally reorganize the indexes of
some other database system to keep response times in the acceptable
range. I wasn't sure if databases had gotten smart enough to take
care of that task themselves.

Thank you, Giovanni, for information


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