Knut Anders Hatlen wrote:
Paul Taylor <[email protected]> writes:
Knut Anders Hatlen wrote:
Paul Taylor <[email protected]> writes:
HI, I use derby in embedded mode, I let the user specify a maxmium
size for the derby database files, my program monitors this and if it
goes over the size I use SQL to delete records that are no longer
necessary in the hope of shrinking the database files size, but it
doesn't, how can I force Derby to shrink back down ?
Hi Paul,
The database files won't shrink unless you compress the tables.
http://db.apache.org/derby/docs/10.6/ref/rrefaltertablecompress.html
http://db.apache.org/derby/docs/10.6/ref/rrefproceduresinplacecompress.html
Hope this helps,
Thanks guys that does help, the only problem is that it takes an
exclusive lock on the table and I wanted to run it in the background
as and when required when other tasks might be going ahead. But can
probaly work round this.
In the issue tracker there's a request for allowing more concurrent
activity while compressing a table, but there hasn't been any work on it
yet. https://issues.apache.org/jira/browse/DERBY-3974
I dont quote get the difference between the two procedures, one makes
adjustments in place, the other doesnt, but they both exclusively lock
the table so what is the advantage of one over the other ?
Paul
