Re: Deleted records and index size

[Charles Wilt <charles.wilt@xxxxxxxxx>]

I think the answer is "it depends" :)

A standard index on the i is a binary radix index, just like other
platforms.  A page of data would contain many keys.  So if you delete one
in the middle, you'd obviously have a "empty space" and not immediately get
any space back.

However, unlike other platforms, the OS automatically handles "periodically
reorganize or rebalance the index structures...as part of the normal index
maintenance processing that occurs as key values are being inserted,
updated, and deleted."
per:
http://www-304.ibm.com/partnerworld/wps/servlet/ContentHandler/stg_ast_sys_wp_db2_i_indexing_methods_strategies

I'd seriously doubt the OS would reorganize the index of a billion record
table after you delete a single row.  But I don't know of any documents
that tell when it would.

Charles



On Mon, Feb 3, 2014 at 1:57 PM, Alan Campin <alan0307d@xxxxxxxxx> wrote:

> Does anybody know. If you delete a record, does the index size decrease?
>
> I am getting indications both way, that it keeps the deleted record in
> index and logical indexes and other stuff that seems to say it deletes the
> record from the indexes.
>
> I found IBM's information on calculating index size but it only says number
> of records and nothing about deleted record.
>
> It would seem logical that it would not keep an entry in the index.
>
> Anyway, thanks. .
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