1.271 PGA_AGGREGATE_LIMIT
PGA_AGGREGATE_LIMIT
specifies a limit on the aggregate PGA memory consumed by the instance.
Property | Description |
---|---|
Parameter type |
Big integer |
Syntax |
|
Default value |
If If If In all cases, the default For a PDB, the default value is the same as the CDB's default value. |
Modifiable |
|
Modifiable in a PDB |
Yes |
Range of values |
Do not attempt to set |
Basic |
No |
Actions Taken When PGA_AGGREGATE_LIMIT is Exceeded
Parallel queries will be treated as a unit. First, the sessions that are using the most untunable memory will have their calls aborted. Then, if the total PGA memory usage is still over the limit, the sessions that are using the most untunable memory will be terminated.
SYS processes and background processes other than job queue processes will not be subjected to any of the actions described in this section. Instead, if they are using the most untunable memory, they will periodically write a brief summary of their PGA usage to a trace file.
Note:
This parameter is optional for pluggable databases (PDBs). When this parameter is set for a PDB, it specifies the maximum PGA size for the PDB.
To be able to use Resource Manager in a CDB to control the amount of memory each PDB can use:
-
The
NONCDB_COMPATIBLE
initialization parameter must be set toFALSE
at the CDB level (in the root of the CDB). -
The
MEMORY_TARGET
initialization parameter must not be set at the CDB level. -
You must set the
PGA_AGGREGATE_LIMIT
initialization parameter in a PDB to a value that meets these requirements:-
Less than or equal to the
PGA_AGGREGATE_LIMIT
value set at the CDB level -
Greater than or equal to twice the value of
PGA_AGGREGATE_TARGET
set in the PDB
When you set
PGA_AGGREGATE_LIMIT
in a PDB to a value that does not meet these requirements, you receive an error. If these requirements are violated after the PDB’s parameter is set (for example, if thePGA_AGGREGATE_LIMIT
value is changed at the CDB level, Oracle will adjust the PDB’s value to meet these requirements. -
See Also:
-
Oracle Multitenant Administrator's Guide for more information about the initialization parameters that control the memory usage of PDBs
-
Oracle Database Performance Tuning Guide for more information about this parameter