Modify the Oracle SGA to improve Oracle performance __oracle

Modify the Oracle SGA to improve Oracle performance Under normal circumstances, the query is very slow.
1, check the SGA size, as a DBA to connect to the Oracle database, input show SGA.
2, if the SGA is too small, please modify its size
To modify the principle that the SGA must maintain:
1). Sga_target cannot be greater than sga_max_size and can be set to equal.
2). The total amount of memory consumed by other processes, such as the SGA plus the PGA, must be less than the operating system's physical memory.
You must back up all the files in the DBS directory before you do the following.
Method one: Direct SQL command line modification:
(If the SPFile file does not exist, create SPFile from Pfile is created first;)
Sql>alter system set sga_max_size=1024m scope=spfile;
Then you need to restart the database
Sql>shutdown Immediate
Sql>startup
Sql>show SGA; You can see the size of the SGA has been modified
After reboot, modify Sga_target
Sql>alter system set sga_target=1024m Scope=both;




Method Two: Modified by EM:
Log in sys to EM: admin-> (Database configuration) All initialization parameters->spfile-> this interface can directly define Sga_target and Sga_max_size
Then restart the database