Oracle Index Key compression, Problem with ind_comp.get_column('Tablename')

[Former Member]

Hi all,

I have came accross OSS Note 1109743 - Use of Index Key Compression for Oracle Databases and I'm interested in implmenting it.

I've done some testing on a few tables and works fine but I'm having a problem using ind_comp.get_column('Tablename') on some tables. When I run it in our UNIX environment it creates a file <table_name>_IX_COMP.sql in /tmp directory. For some tables this file is empty. I can't work out why.

I realise that it will only work on Btree indexes, but if we take table VBOX for example. This tables has 2 indexes, VBOX_{0 and VBOX}A. My understanding is VBOX~0 is Unique Btree index and VBOX~A is Non-Unique B*tree index.

Can anyone explain to me why this is happening. Or is there a manual way to calculate the compression factor.

Thank you

[former_member569256]

This happens when the script finds the compression of the indexes will bring no benefit.

Regards,

Markus.