Question about Index (Rebuild or not )

I have read somewhere (about when an index need to be drop and rebuild ).
It said that I have to run ANALYZE INDEX command to validate Structure, then
calculate the ratio of LF_BLK_LEN/(LF_BLK_LEN+BR_BLK_LEN). If it is not greater that 0.7 then the ratio should be rebuild. It also said that if the ratio of LF_BLK_LEN/(LF_BLK_LEN+BR_BLK_LEN) is nearing 0.3, the index
definitely need to be drop and recreate or Rebuild.

Well, I have just create a new table say.. TABLE_A. I also created an index
in one of the column. When the table is empty, I run the ANALYZE INDEX command
to validate Structure and calculate the ratio of LF_BLK_LEN/(LF_BLK_LEN+BR_BLK_LEN).
The result is 1.0.
Then, I load the data into that table using sqlload (about 1.3 million record).
After loading the data, I ran the ANALYZE INDEX command + calculate the ratio
of LF_BLK_LEN/(LF_BLK_LEN+BR_BLK_LEN). The result is 0.49.

According to the article that I read, (if I am not misinterpreting it) I have to
rebuild to index. Therefore, I drop the index and create it again. Afterward,
I run the ANALYZE INDEX + Calculate the ratio. The result is 0.49 again.

Then, I try to rebuild it and do the ANALYZE INDEX + Calculating the ratio.
I got 0.49 again.

My question:
Why I can get the ratio to be nearing 1.0 ( or at least over 0.7 ) ? Or did I do anything wrong ? If I did something wrong, then how to determine if an index need to be dropped and rebuild ?

Thanks for all the help

Assoy

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Before you buy. Received on Wed Oct 06 1999 - 21:20:03 CDT