Latter company technology, research and development is asking how I install the function that can optimize Oracle about memory parameter, smoked time to arrange this documentation so, in order to make reference.
Purpose:
The hope is passed arrange this documentation, make the company works in the same place to have a comprehensive knowledge to Oracle memory structure, apply neatly in real work, make the memory function of Oracle achieves best configuration, promotion uses program response rate, undertake reasonable memory use.
Example structure
Structure of memory of Oracle example = process structure
The process that Oracle example starts, the value to load that is setting of Oracle memory parameter actually arrives in memory, start corresponding tiring-room process to have relevant service process.
Process structure
Process of server of Oracle process = user process
A few significant tiring-room progresses:
DBWR: Data keeps a process.
LGWR: Overspread Ju Ciguo ?
ARCH: Does Lv arrive ?
CKPT: After an examination is nodded, the daily record that surpassed designation time; to be defined beforehand again piece write Cheng of disk; exemple to shut, DBA arises compulsively, express dimensional Offline)
LCKn(0-9) : Block process.
Dnnn: Ju Ran ?
Memory structure (we explain mainly)
Area of overall situation of system of memory structure =SGA() area of PGA(program overall situation)
SGA is the main target that the memory shift that we say actors or actress. We install SGA namely mainly
Principle: SGA PGA OS uses RAM of memory < total physics
1, area of SGA system overall situation. (Include the following 5 areas)
Buffer of A, data: (The data that Db_block_buffers) memory reads in by disk data file.
Size: Db_block_buffers*db_block_size
Oracle9i installs data buffer to be: Db_cache_size
Principle: The target basically is set in SGA, it is usable memory commonly 40% .
B, share a pool: (Shared_pool_size) : Feng is worth amortize of clear 瑂 Ql, PL/SQL parse. Increase can raise rate.
Principle: The target basically is set in SGA, it is usable memory commonly 10%
Buffer of C, log: (The modification information of Log_buffer) memory database.
Principle: 128K----Between 1M, not too should big
Pool of D, Java (the development that Java_pool_size) basically uses at JAVA language.
Principle: If do not use Java, in principle cannot be less than 20M, to 30M normally enough
E, big pool (if Large_pool_size) does not install MTS, basically use at database backup to restore to manage implement RMAN.
Principle: If do not use MTS, 5----Between 10M, not too should big
SGA= . Db_block_buffers*db_block_size Shared_pool_size Log_buffer Java_pool size large_pool_size
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