What is the SAP HANA Resource Container?
The SAP HANA resource container is composed of the row store and heap allocators along with the information which can be re-used such as:
- SAP HANA page cache (Pool/PersistenceManager/PersistentSpace/DefaultLPA/Page)
- Column store tables
SAP HANA resource container doesn't cover heap areas which can't be re-used - particulary related to SQL statement data processing, e.g.:
- Pool/itab
- Pool/JoinEvaluator/JEAssembleResults
- Pool/parallel/aggregates
- Pool/RowEngine/MonitorView
- Pool/TableConsistencyCheck
There is no easy method or approach for identifying the allocators assigned to the resource container.
User can use SQL: 'HANA_Memory_MemoryObjects' (SAP Document 1969700) for checking the current population of the resource container. Also the hdbcons command 'resman info' (SAP Document 2222218) gives user general information regarding the current status of resource container.
In case if some additional memory is required and not available, then SAP HANA can shrink the resource container (e.g. by reduction of certain heap allocators or unloading columns).In this case the database trace (SAP Document 2380176) will contain an entry like the following:
Information about shrink at <date> <time> Local: Reason for shrink: Precharge for big block allocation.
The hdbcons command "resman shrink", as e.g. proposed in SAP Document 2301382, only works on the resource container, therefore the external allocators can't be shrunk with this command.