Re: detached index vs attached index

Hi! Is there any easy way to detach indexes in OnLine 5.x and upwards? At 05:57 PM 9/10/97 EDT, you wrote: } }>Greeting... }> }>Can anyone comment on detached index vs attached index? Thanks in }>advance! }> }>Andy Chang } }At one time, Informix often made an issue about the fact that the indexes }were attached. By attached, we mean that the index is actually contained }in the same partition (tablespace) that the data pages are located in. The }thought was that the disk seek time would be shorter if the index pages }were located physically as close to the data pages as possible.This was }true with small memory systems with single user applications. By reading }the index page, there was a rather good possibility that the data page }would be close by. } }However, with larger memory/multi-user systems, this is no longer as much }of a concern because there is a rather small probability that the read of }an index item will be followed by a read of the data item. There is a much }larger probability that the read of the index item will be followed by a }read from some other user thread. Instead, we are trying to speed-up }things like read-ahead. By seperating the index from the data pages, we }can improve performance on scans because the actual scan does not have to }"skip over" index pages. Also, by detaching the index, the dba can do }things like insure that the datapages and the index pages are not on the }same spindle. This should help in the performance of batch type jobs. } }All in all, I think detached indexes are a good feature in today's }environments. }Madison Pruet } Best regards, Nigel +-------------------------------------------------------------+ |Name : Edmund Nigel Gall Tel: (868) 636 3153 | |Title : Information Systems Specialist Fax: (868) 679 3770 | |Company: Process Plant Services Limited | |Address: Atlantic Avenue, Point Lisas Industrial Estate | | Point Lisas, Couva, Trinidad & Tobago, W.I. | +----- mailto:nigelg@ppsl.com ------ http://www.ppsl.com -----+