|Oracle® Database Reference
11g Release 2 (11.2)
|PDF · Mobi · ePub|
|Range of values||Minimum: the value equivalent of six database blocks
Maximum: operating system-dependent
Note:Oracle does not recommend using the
SORT_AREA_SIZEparameter unless the instance is configured with the shared server option. Oracle recommends that you enable automatic sizing of SQL working areas by setting
SORT_AREA_SIZEis retained for backward compatibility.
SORT_AREA_SIZE specifies (in bytes) the maximum amount of memory Oracle will use for a sort. After the sort is complete, but before the rows are returned, Oracle releases all of the memory allocated for the sort, except the amount specified by the
SORT_AREA_RETAINED_SIZE parameter. After the last row is returned, Oracle releases the remainder of the memory.
SORT_AREA_SIZE size improves the efficiency of large sorts.
Each sort in a query can consume memory up to the amount specified by
SORT_AREA_SIZE, and there can be multiple sorts in a query. Also, if a query is executed in parallel, each PQ slave can consume memory up to the amount specified by
SORT_AREA_SIZE for each sort it does.
SORT_AREA_SIZE is also used for inserts and updates to bitmap indexes. Setting this value appropriately results in a bitmap segment being updated only once for each DML operation, even if more than one row in that segment changes.
Larger values of
SORT_AREA_SIZE permit more sorts to be performed in memory. If more space is required to complete the sort than will fit into the memory provided, then temporary segments on disk are used to hold the intermediate sort runs.
The default is adequate for most OLTP operations. You might want to adjust this parameter for decision support systems, batch jobs, or large
CREATE INDEX operations.