100 Oracle TimesTen In-Memory Database Installation Guide
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 -
noRepUpgrade option.
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
