ALTER SYSTEM SET
When we issue ALTER SYSTEM SET to modify parameter, some scope clauses can be used to specify how new value is applied in the database. For example:
Without specifying any of these clauses, they fall into their own default values according to the context, which define the final applicable range of the parameter.
1. SCOPE Clause
If you do not specify this clause, then:
- SPFILE
- PFILE
If a server parameter file (SPFILE) was used to start up the database, then BOTH is the default.
If a parameter file (PFILE) was used to start up the database, then MEMORY is the default, as well as the only scope you can specify.
| Started by | SCOPE |
|---|---|
| SPFILE | BOTH |
| PFILE | MEMORY |
2. SID Clause
If you do not specify this clause, then:
- SPFILE
- PFILE
If the instance was started up with a SPFILE (server parameter file), then Oracle Database assumes SID = '*'.
If the instance was started up with a PFILE (traditional plain-text initialization parameter file), then Oracle Database assumes the SID of the current instance.
| Started by | SID |
|---|---|
| SPFILE | * (All instances) |
| PFILE | (Current instance) |
3. CONTAINER Clause
If you omit this clause, then CONTAINER=CURRENT is the default, not CONTAINER=ALL.