Oracle-L: RE: Sequence number generation

From: Cary Millsap <cary.millsap_at_hotsos.com>
Date: Thu, 18 Jul 2002 07:33:24 -0800
Message-ID: <F001.0049B3CE.20020718073324@fatcity.com>

But be careful! Using tables for sequence numbers is a dead-certain guarantee that your application can never scale. The only way you can avoid performance problems with this kind of application design is to never let a lot of users use the system.

If the locks don't kill you, then contention for the cache buffers chains latches will. Since your buffer clones all have the same fileid and blockid, they'll always be on the same chain in the buffer cache hash table. No amount of memory, no SGA size, and no setting of _db_block_hash_buckets or _db_block_hash_latches can save you.

Cary Millsap
Hotsos Enterprises, Ltd.
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-----Original Message-----
Aleem
Sent: Thursday, July 18, 2002 2:38 AM
To: Multiple recipients of list ORACLE-L

To have a better control, we always use tables for holding counters. Depending upon the requirement, either one table to hold different counters
or multiple tables, sometime in master tables as well.

This does not any additional coding, the trigger in which you fetch from sequence you select from table. To keep it synchronized with the transaction, we make counter table block

HTH! Aleem
-----Original Message-----

Sent:	Thursday, July 18, 2002 11:48 AM
To:	Multiple recipients of list ORACLE-L
Subject:	RE: Sequence number generation

It is not possible to avoid sequence number loss . If a user requests a sequence number, then ultimately rolls back that transaction,
that sequence number is lost .

However you can catch such lost sequence numbers programatically and reuse
then.
that would require a bit of extra coding.

-----Original Message-----
Sent: Thursday, July 18, 2002 10:43 AM
To: Multiple recipients of list ORACLE-L

Hi
Is it possible to avoid sequence number loss in the sequence number generation. if so how?

Thanks in Advance

Ayyappan.S

"Dreams translate into thoughts, and
thoughts translate into action: Kalam"

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Received on Thu Jul 18 2002 - 10:33:24 CDT