db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Oystein.Grov...@Sun.COM (Øystein Grøvlen)
Subject Re: Behaviour of SYSCS_COMPRESS_TABLE
Date Wed, 01 Jun 2005 08:40:11 GMT
>>>>> "MM" == Mike Matrigali <mikem_app@sbcglobal.net> writes:

    MM> Note that cloudscape automatically reuses space from deleted rows when
    MM> new rows are inserted into the table.  The main problem
    MM> SYSCS_COMPRESS_TABLE is solving is if there are a number of deletes
    MM> which will not be followed by a number of inserts.  The reuse of space
    MM> is not as efficient as the compress table at it squeezes every last bit
    MM> of free space out, and returns that space to the OS.

Is this also true for B-tree indexes?  I would imagine that if you
have a index on a monotocally increasing key (e.g., a timestamp) and
where you regularly delete old records, there may be a lot of empty
B-tree pages that will never be possible to reuse.


View raw message