Oracle Audio Technologies B31679-01 manual Reducing data store size

Reducing data store size

Once a data store has been defined with a particular size for the permanent partition (indicated by the PermSize DSN attribute), it cannot be loaded at a smaller size, even if tables or rows are deleted. A copy of the data store made with ttBackup also has the data store’s permanent partition size embedded in it.

To reduce the allocated size of the permanent partition of a data store, save a copy using the ttMigrate utility with the -noRepUpgradeoption. Then recreate the data store with a smaller permanent partition size and restore the data.

Note: The permanent partition size of a data store cannot be reduced below the size that is actually required by the data currently stored in the data store. This value can be determined by querying the perm_in_use_size column of the table sys.monitor.

Perform these steps to reduce the permanent partition size of a data store:

1.Back up the old data store with ttMigrate -c-noRepUpgrade.

2.Create a new DSN definition for the new copy of the data store with a smaller PermSize value.

3.Restore the backup with ttMigrate -r-noRepUpgrade.

Note: If you wish to use the original DSN rather than create a new one in Step 2, then you must first destroy the original data store files using the ttDestroy utility.

Here are the steps to reduce a data store’s allocated size from 400 MB to 100 MB. The data store is in /ds/Sales/Data and has the Data Source Name (DSN) salesdata.

1.ttMigrate -c DSN=salesdata -noRepUpgrade /tmp/salesbackup

2.ttDestroy /ds/Sales/Data

3.Update the DSN salesdata to have a size of 100 MB. See "Changing data store size" in the Oracle TimesTen In-Memory Database Operations Guide.

4.ttMigrate -r "DSN=salesdata;AutoCreate=1" -noRepUpgrade /tmp/salesbackup

100 Oracle TimesTen In-Memory Database Installation Guide