Oracle建庫必備的核心初始化引數

安裝完資料庫軟體的下一步就是建立資料庫，如果是手工建立資料庫或對資料庫所佔用的記憶體進行一些合理化配置，就需要理解必備的建庫初始化引數。

今天在手工建庫過程中，發現$ORACLE_HOME/dbs/下的init.ora和initdw.ora兩個檔案內容也是值得讀一遍。因此產生了Oracle建庫必備的核心初始化引數有哪些的想法，總結如下：

1、Oracle 9i 環境

以1G實體記憶體為例，給OS留50%，其餘用於Oracle。在Oracle9i提出了pga_agregate_target引數。

db_name = MY_DB_NAME

control_files = (ora_control1, ora_control2)

shared_pool_size = 50M

pga_aggregate_target = 200M

db_cache_size = 200M

undo_management = auto

undo_tablespace =undotbs1

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當然還有其他的引數，initdw.ora檔案中介紹的也是非常詳細，在此只是列出必備的。

# Memory is managed globally. The DBA should first determine how much

# memory is available for Oracle to use. Then, the DBA should choose

# memory parameters so that pga_aggregate_size + db_cache_size +

# shared_pool_size + large_pool_size is roughly equal to the amount

# of memory available for the Oracle database.

#

# For example, suppose that a DBA is managing a small data mart. The

# data mart server has 1GB of physical memory. The DBA has determined

# that 500M of memory will be used by the operating system and other

# applications, so that 500M is available for Oracle.

#

# The DBA may choose the following settings:

# shared_pool_size = 50M

# pga_aggregate_size = 200M

# db_cache_size = 200M

# large_pool_size =

#

# The total memory utilization is 450M plus a system-determined value

# for the large pool.

# pga_aggregate_target should, in general, be equal to 20-80% of the

# available memory, depending on the workload.

# db_cache_size should, in general, be equal to 20-80% of the

# available memory, depending on the workload.

# Shared pool size should be, in general, equal to 5-10% of the

# available memory.

2、Oracle 10g 環境

在Oracle10g，提出sga_max_size和sga_target引數

db_name = MY_DB_NAME

control_files = (ora_control1, ora_control2)

pga_aggregate_target = 200M

sga_target= 250M

undo_management = auto

undo_tablespace =undotbs1

3、Oracle 11g 環境

類似SGA_MAX_SIZE與SGA_TARGET一樣，MEMORY_MAX_TARGET與MEMORY_TARGET成對出現，這一特性的出現使得PGA+SGA作為整體記憶體使用被一致的納入自動管理範疇。。

在Oracle10g，提出sga_max_size和sga_target引數

db_name = MY_DB_NAME

control_files = (ora_control1, ora_control2)

memory_targe=450M

MEMORY_MAX_TARGET=450M

undo_management = auto

undo_tablespace =undotbs1

與Oracle10g類似，設定了自動記憶體管理之後，PGA_AGGREGATE_TARGET引數不再需要設定，取而代之發揮作用的引數是帶有2個下劃線的__PGA_AGGREGATE_TARGET引數