Which initialization parameters most affect Oracle system performance

oracle| performance which initialization parameters most affect Oracle system performance
What is the SGA (System global Area) 1, the System global Area (SGA) is a control information memory segment assigned to Oracle that contains an Oracle instance database.
Mainly includes the database cache cache (buffer cache),
Replay log cache (the redo log buffer)
Shared Pool,
Data dictionary caching (the dictionary cache) and other information.
Db_block_buffers 1, data high speed buffer
2, access to the data are placed in this piece of memory area, the larger the parameter, Oracle in memory to find the same data, the greater the likelihood, that is, speed up the query speed.
3, db_block_buffers to block as a unit, if db_block_size=2k,db_block_buffers=3200, then occupy memory =3200*2k=6400k.
Share_pool_size 1, SQL shared buffer pool
2, this parameter is the cache of the library cache and the data dictionary.
Log_buffer 1, Replay log buffer
Sort_area_size 1, sorting area
Processes 1, simultaneous number of processes connected
Global_names 1, set global_names = TRUE If the database link name and the database to which it is connected have the same name.
Otherwise, set global_names = FALSE
Db_block_size 1, database block size
2, the Oracle default block is 2KB, too small, because if we have a 8KB of data, the 2KB block database to read 4 times to read,
and 8KB block of database as long as 1 read, greatly reduced I/O operation.
3, after the completion of the database installation, you can no longer change the value of the db_block_size, you can only re-establish the database
And when you build a library, you choose to install the database manually.
Open_links 1, number of links open at the same time
Dml_locks 1, the maximum number of locks that a user can set on a table at one time
2. If three users modify 6 tables, 18 DML locks are required to achieve parallel operations, if the set dml_locks is not large enough, the operation will be interrupted, you can use the size of your application and the maximum number of users in parallel to estimate the value of the system needed dml_locks, However, the size of the value of the database does not affect the other performance, so it is generally set to a large, far more than the actual value can be achieved, if the system is running in the event of a frequent table lock, you should consider increasing the value.
Open_cursors 1, open cursor number
2. This parameter can be owned by each user process at the same time, and the maximum value of this parameter varies according to the operating system.
3. When you create a composite view that contains many tables, the view creation is unsuccessful if this parameter is small.
Dbwr_io_slaves 1, background write process number