This document provides instructions on setting up memory_ttl to save memory on low usage columns
Affects versions: 6.1, 6.2
Kinetica includes a feature called memory_ttl which allows Kinetica to unload from memory columns that have been idle for the time specified in the memory_ttl setting.
Unloaded columns will then be loaded back into memory when required by a request such as get_records_by_column.
GADMIN will still show the column values when looking at the tables, but the Info tab will show the column memory utilization as 0.00 MB.
Note: memory_ttl should not be confused with table ttl which controls the expiration of the entire table. memory_ttl is global and can only be set on gpudb.conf.
By default the memory_ttl is set to infinite which prevents the columns to be unloaded, to change this setting:
- Navigate to: /opt/gpudb/core/etc/ and edit gpudb.conf
- Find the line
- Change to the desired time in minutes (i.e. memory_ttl=5)
- Save gpudb.conf
- Restart Kinetica
Once the time expires, the table information window will look similar to this:
If the columns are queried, the information window will look similar to this:
If the entire table is loaded, it looks like this: