Fragmented index question
IDS 11.70.fc2 Aix 6.1 I have a question for the experts...When fragmenting a non unique index, you can fragment the index by a column that isn't part of the index .. So, when it's an unique index, why does the column being fragmented by .. have to be part of the index? Peter Peter Logan Senior Database Administrator Phone: 616/878-8309
Peter, If a fragmented unique index does not contain keys used in the fragmentation schema. Then the DB will need to check every index fragment before it can determine if a newly added key is unique. This in itself would make things messy add to this the locking that would need to be done to avoid accidental duplicates and you have now made it more trouble then it would be worth to attempt to implement. George. From: "Peter_Logan@spartanstores.com" <Peter_Logan@spartanstores.com> To: ids@iiug.org Date: 06/30/2011 09:19 AM Subject: Fragmented index question [24191] Sent by: ids-bounces@iiug.org IDS 11.70.fc2 Aix 6.1 I have a question for the experts...When fragmenting a non unique index, you can fragment the index by a column that isn't part of the index .. So, when it's an unique index, why does the column being fragmented by .. have to be part of the index? Peter Peter Logan Senior Database Administrator Phone: 616/878-8309 ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.
Didn't think about it that way ... thanks ... Peter Logan Senior Database Administrator Phone: 616/878-8309 From: "George_Palmer@aotx.uscourts.gov" <George_Palmer@aotx.uscourts.gov> To: ids@iiug.org Date: 06/30/2011 10:28 AM Subject: Re: Fragmented index question [24192] Sent by: ids-bounces@iiug.org Peter, If a fragmented unique index does not contain keys used in the fragmentation schema. Then the DB will need to check every index fragment before it can determine if a newly added key is unique. This in itself would make things messy add to this the locking that would need to be done to avoid accidental duplicates and you have now made it more trouble then it would be worth to attempt to implement. George. From: "Peter_Logan@spartanstores.com" <Peter_Logan@spartanstores.com> To: ids@iiug.org Date: 06/30/2011 09:19 AM Subject: Fragmented index question [24191] Sent by: ids-bounces@iiug.org IDS 11.70.fc2 Aix 6.1 I have a question for the experts...When fragmenting a non unique index, you can fragment the index by a column that isn't part of the index .. So, when it's an unique index, why does the column being fragmented by .. have to be part of the index? Peter Peter Logan Senior Database Administrator Phone: 616/878-8309 ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum. ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.