Re: Help: Reducing Extents -Reply

Just a comment about Gregs posting. I have also used fragment to rewrite a non-fragmented table in place. I have found afterwards a high likelihood of receiving 243/172 errors on such tables. This seems to be reduced if they are [de]fragmented into a different dbspace that they are currently in. But I have basically abandoned using it now and gone back to using clustered indexing which [appears to be | is ] less flakey. rgds Peter Tashkoff <tashkop@zespri.co.nz> Zespri International Limited This posting may not be used by any party to vilify another. Standard disclaimers apply. >>> Greg <greg@cyberramp.SPAMCHOKER.net> 16/June/1997 04:07pm >>> Chad, after increasing the NEXTSIZE in systables (don't worry too much about the first extent, it'll tend to be coalesced pretty well unless you have a lot of fragmented tables in the same dbspace). two methods not mentioned are: 1. use onunload/onload - it's waaaay faster than dbexport/dbimport, but takes more disk or tape space and you can't edit the schema before onload.... 2. use "alter fragment on table <tablename> init in <dbspacename>" - I really like this one because it requires only knowledge of the tablename and where you want it to go. The clustered index oriented strategies require you to look up stuff for each table that has little to do with the job at hand. Alter fragment is much simpler..... Anyway, you have advice out the keister now, let us know how it goes.... Greg p.s. >5 extents isn't necessarily a performance killer, if you have enough memory to keep your read hit ratio high (> 99ish percent), you won't be able to tell the difference between 3 extents and 30 extents. You are at a point it's probably worthwhile to clean up a little. I try to organize it so I only have to reorganize things a couple of times a year. Chad Laity wrote: snip.... > How do I reduce the number of extents to improve performance?? > > Thanks, > Chad Laity > chad_laity@arrowintl.com > wick@fast.net -- Please remove SPAMCHOKER. to get correct EMail address...thanks.