Re: fragmented system tables

Sven Tolkemit wrote: > Hi people, On the broad assumption thatthis includes programmers, I will at least comment. > we discovered, that the system tables (systables,sysindexes, etc.) on > our Online 7.23.UC1 are very fragmented. We think, this leads into > performance problems. Is there a way to defragment the tables? In a different thread, someone (Art K?) pointed out that the system tables (i.e. partition headers) are loaded into memory and seldom released. The fragmentation of the system catalogs should, therefore, be of little consequence; all fragments of the catalog are already accounted for in the partition header page for that catalog. Only the hash parameters (DD_HASHSIZE, DD_HASHMAX) may have some effect on how many catalog rows can be kept in memory. I *have* seen a situation where someone had such a convoluted system with such a fragmented syscolumns that the system could not add any more extents to syscolumns. This was a 5.x system; I don't believe that would be a restriction anymore. It would be interesting to see if ALTER TABLE NEXT EXTENT works on a system catalog before the catalog gets fragmented. I think so but I have never tried it. -- -- Jake (Retrospectively realizes there is no future in hindsight) +------------------------------------------------------------+ | The expedient performance of a task with excessive concern | | regarding its duration-to-completion engenders a virtual | | certainty of diminished benefit therefrom. | | -- Benjamin Franklin (but he said it in 3 words) | +------------------------------------------------------------+