Oracle Instance on the path of OracleDBA (III)

Modify the SPFILE Value
Log on to the Oracle server and use related commands to modify the corresponding values.
Alter system set parameter = value <comment = 'text'> <deferred> <scope = memory | spfile | both> <sid = 'sid | * '>
Sid = 'sid | *'
The default value is *, indicating all instances. Generally, the next Instance corresponds to a Database. If it is RAC (one Database corresponds to multiple instances), you must specify different SID.
<Scope = memory | spfile | both>
Memory: only modify memory Parameters
Spfile: only change files on the disk
Both: both are modified. If this parameter is not specified, both is applied by default.
<Deferred> some parameters are not currently modified and will be modified at next startup.
<Comment = 'text'> comment
Example:
Take the value of fast_start_mttr_target as an example:
First, check the default value of the fast_start_mttr_target parameter.
Show parameter fast_start_mttr_target;
Name type value
Fast_start_mttr_target integer 300
Modify:
Alter system set fast_start_mttr_target = 250;
System altered;
View the modified value (memory)
Show parameter fast_start_mttr_target;
Name type value
Fast_start_mttr_target integer 250
View spfile values
Exit sqlplus
Go to the $ ORACLE_HOEM/dbs directory
Strings spfileSID. ora
*. Fast_start_mttr_target = 250
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We only modify the value in the memory.
Alter system set fast_start_mttr_target = 260 scope = memory;
System altered;
View the modified value (memory)
Show parameter fast_start_mttr_target;
Name type value
Fast_start_mttr_target integer 260
View spfile values
Strings spfileSID. ora
*. Fast_start_mttr_target = 250
The modification of spfile is similar to that of memory. You only need to replace the value of scope with that of spfile.
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The comment value is stored in the updata_comment column of V $ parameter.
Alter system set fast_start_mttr_target = 260 comment = 'Hello word ';
View comment values
Select name, value, updata_comment from v $ parameter where name = fast_start_mttr_target '';
Name value UPDATA_COMMENT
Fast_start_mttr_target 260 hello word
View comment in spfile
*. Fast_start_mttr_target = 260 # hello word
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View which parameters need to be set deferred
Select name, issys_modifiable from V $ parameter where issys_modifiable = 'referred'
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If you want to apply the value that comes with the system, use the alter system reset command.
Alter system reset PARAMETER_NAME scopt = memory | spfile | both SID = 'sid | *';