Reducing database usage of disk space

Posted by daniel.baciu on 23-May-2019 06:14

Hi,

Is there to reduce the disk space a database uses, other way than dump & load ?
We cleaned up some large tables in the prod database, but meanwhile we get to the maxim space we have now available.

Moving extents to a different volume is not an option for the moment.

Daniel.

Posted by hjboxem on 23-May-2019 10:50

It depends. If the data was removed from an Area other than the Area which contains the tables that are growing fast you would be facing a challenge. When using Storage Area type II with large(r) cluster sizes, those freed blocks couldn't be allocated by other tables because each table uses it's own clusters. And if that isn't fully cleaned it remains allocated for that table. Unless the tables that are cleaned up are the same ones that are growing (fast).

Did you run a database analysis before and after the cleaning? You should run these on a regular (weekly) basis to give you an idea on what's happening with your data. Otherwise you are looking at a "black database".

Posted by James Palmer on 23-May-2019 09:15

If you've removed data from the database, then the only way to see that reflected on disk is to do a dump and load. But, the database engine will reuse that allocated space for new data, so you shouldn't see the database grow in the meantime.

All Replies

Posted by James Palmer on 23-May-2019 09:15

If you've removed data from the database, then the only way to see that reflected on disk is to do a dump and load. But, the database engine will reuse that allocated space for new data, so you shouldn't see the database grow in the meantime.

Posted by hjboxem on 23-May-2019 10:50

It depends. If the data was removed from an Area other than the Area which contains the tables that are growing fast you would be facing a challenge. When using Storage Area type II with large(r) cluster sizes, those freed blocks couldn't be allocated by other tables because each table uses it's own clusters. And if that isn't fully cleaned it remains allocated for that table. Unless the tables that are cleaned up are the same ones that are growing (fast).

Did you run a database analysis before and after the cleaning? You should run these on a regular (weekly) basis to give you an idea on what's happening with your data. Otherwise you are looking at a "black database".

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