Oracle-L: RE: Commit boundary <-> Stripe Unit Size Co-relation

From: VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com>
Date: Wed, 12 Feb 2003 22:38:39 -0800
Message-ID: <F001.0054B780.20030212223839@fatcity.com>

Dennis , Connor , List

Further a very vague Qs.

For Batch Jobs , we get extremely DIFFERENT performances when using DIFFERENT Stripe Unit Sizes of 4K , 64 K , 128K , 512K , 1M , 2M WITH 128K performing the BEST.

Both SELECTs & UPDATEs Hang almost indefinitely with 512K , 1M , 2M Stripe Unit Sizes .

Average Size Data Inserted/Updated is 5K approx. acrross 7 Tables for one Application Transaction

Thus there Seems Some Co-relation between SELECT/UPDATE/INSERT from Datafiles & Different Underlying Stripe Unit Sizes .

Any Comments ?

Thanks

-----Original Message-----
Sent: Wednesday, February 12, 2003 8:54 PM To: Multiple recipients of list ORACLE-L

Vivek - Just to add to Connor's statements (wow am I being rash here), Oracle's strength is that it's architecture disconnects transactions from disk writes. On one hand, block may be modified several times before being written to disk (hot block, for instance). On the other hand, Oracle may need buffer space and write a block to disk before a transaction commits. But Oracle keeps track of all this and can straighten everything out if the transaction is rolled back or the system crashes.

Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Wednesday, February 12, 2003 12:04 AM To: Multiple recipients of list ORACLE-L

CASE - If Size of 1 INSERT/UPDATE Statement = 1K & Stripe Unit Size is 128 K ?

How will 1 COMMIT issued after 300 "1K" INSERT/UPDATE Statements DIFFER from 1 COMMIT issued after EACH "1K" INSERT/UPDATE Statement with respect to Writing to the datafiles on the Underlying Striped Volume ?

If 1 INSERT Statement Data is Written to the 1st Disk (say) of the Striped Volume , will a Repeat of the SAME INSERT Statement Write to a Different Underlying Disk of the same Striped Volume within the SAME Segment Extent ?
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Author: VIVEK_SHARMA
INET: VIVEK_SHARMA_at_infosys.com

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