gaqsharp.blogg.se - Oracle database inmemory

If you are using AMM (MEMORY_TARGET), you will need to extend this to account for the INMEMORY_SIZE parameter value.In a multitenant environment, the INMEMORY_SIZE parameter must be set in the CDB if any of the PDBs need access to the IM column store. Remember, the IM column store is part of the SGA, so the SGA must be capable of containing the amount of memory you want to assign to the INMEMORY_SIZE parameter.

IM Column Store Data Population Options.

Initialization Parameters Related to the IM Column Store.

If you choose badly, you will waste a lot of memory that could be used by the buffer cache.įull lists of initialization parameters, compression methods and population options are available from the documentation. If you choose wisely you will see big improvements in performance. The important thing to remember here is *you* will be responsible for deciding which objects will benefit the most from inclusion in the IM column store.

Queries with multiple large table joins.

Queries that return large numbers of rows.

Queries that return a large number of columns.

It also states it is not designed for the following.

Queries that join small tables to large tables.Queries that return a small number of columns from a table with a large number of columns.Large scans that apply "=", "" and "IN" filters.The documentation claims the IM column store is good for the following. The following commands have been modified to include additional in-memory clauses.īasic examples of their use will be shown below. Alternatively, you can enable IM column store at the tablespace level, so all tables and materialized views in the tablespace are automatically enabled for the IM column store. You can choose to store specific groups of columns, whole tables, materialized views or table partitions in the store. The In-Memory column store is a new section of the SGA, sized using the INMEMORY_SIZE initialization parameter. The IM column store is a separately licensed option of Oracle Database Enterprise Edition.