Re: Question on page compression

In <1993Oct14.123106.8880@rexago8.uucp> bi41@rexago8.uucp (Peter Francescani) writes: >Hi, >Having supported applications which accessed Standard Engine databases >I've seen where tables where unloaded, dropped, re-created and re-loaded >in order to close holes left by end-of-period routines which deleted >many rows. >Is there any reason to continue doing this drop/re-create in an >_OnLine_ environment, where a table's initial extent is large enough >to hold all the rows the table may contain? Will page compression >re-organize the data rows? Page compression only re-organizes rows within a page, not within an extent. In SE, there is a benefit from re-organising a table as described, as it decreases the amount of work involved in doing a sequential scan, and returns disk space to the operating system. In OnLine, there may be a benefit to be gained, but it is less likely. In your scenario of a single extent table, no disk space would be freed. I am not convinced that there is likely to be a significant reduction in the number of data pages, either. And even if there were, I am not convinced that this makes a great deal of difference to performance, as the use of the Big Buffers would imply that many non-data pages would be read in any case. I'd be interested to know what davek and johnl think on this one. graeme -- Disclaimer: The author's opinions are his own, and not necessarily those of Pyramid Technology Ltd. or Pyramid Technology Inc. --------------------------------------------------------------------------- -m------- Graeme Sargent Voice: +44 (0)252 373035 ---mmm----- Senior Database Consultant Fax : +44 (0)252 373135 -----mmmmm--- Pyramid Technology Ltd. Telex: Tell who??? -------mmmmmmm- Farnborough, Hants GU14 7PL Email: graeme@pyra.co.uk --------------------------------------------------------------------------- We have the technology. The tricky bit is learning how to use it.