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Home -> Community -> Usenet -> c.d.o.server -> DBA Tip of the Month: Index Browning
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Index Maintenance
Index browning is the process where btrieve leaf nodes are deleted leaving holes in the index. Under the btrieve structure the vacancies left by data deletion aren't filled. Using the analagy of a tree it is as if the leaf has turned brown because it is dead.
If an index shows excessive browning it will impact performance due to the large number of transversals required to find the required values.
A browned index should be dropped and rebuilt. Determining Index Browning
The number and length of deleted leaf nodes to the total leaf node length and number are important ratios to be considered. These can be calculated as:
% of Leaf Node Length is deleted =
del_lf_rows_len / ( del_lf_rows_len + lf_rows_len )
% of Leaf Nodes are deleted =
del_lf_rows / ( del_lf_rows + lf_rows )
-----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum Received on Thu Sep 17 1998 - 16:10:29 CDT
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