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Home -> Community -> Mailing Lists -> Oracle-L -> Checking the rebuildability of an index
Hi all,
On our ERP DB, 8.1.7.2.0 on HP/UX, I'm finally able to implement an automated index rebuild job. I've got two questions:
First, I've planned to use the gauge of b*-tree HEIGHT and "DEL_LF_ROWS / LF_ROWS) > 20%" from the SYS.INDEX_STATS view to determine what indexes to rebuild. I've read in "Gaja 101" that the leaf block density should also be considered. Is this LF_ROWS / LF_BLKS (from INDEX_STATS)? If so, are there any guidelines as to what the density should be? Or is it only the percentage decrease over time that matters? And if it is, what percentage decrease over what period of time should be considered? This would seem to be very installation-dependant, but I'm just hoping for general guidelines for a starting point so I'm not rebuilding our largest indexes weekly if it's not needed.
Second, how does one determine if there's enough room to REBUILD ONLINE an index? Other than comparing MAX(BYTES) to the INITIAL clause of the index, that is. I've looked in Metalink, "Gaja 101", and several websites, but nothing jumped out at me.
TIA!
Rich Jesse System/Database Administrator Rich.Jesse_at_qtiworld.com Quad/Tech International, Sussex, WI USA
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