db2 学习笔记

来源：作者：出处：巧巧读书 2006-03-30 进入讨论组

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db2 学习笔记

1。手工强制DB2归档

2。Not Logged Initially Option

3。BLK_LOG_DSK_FUL 参数

4。提高备份性能的参数PARALLELISM ,BACKBUFSZ

5。备份到磁盘上的文件名

1。手工强制DB2归档

db2 => ? archive log ?
ARCHIVE LOG FOR DATABASE database-alias [USER username [USING password]]
[On-DbPartitionNum-Clause]

On-DbPartitionNum-Clause:
ON {{DBPARTITIONNUM | DBPARTITIONNUMS} (db-partition-number
[TO db-partition-number] , ... ) | ALL DBPARTITIONNUMS [EXCEPT
{DBPARTITIONNUM | DBPARTITIONNUMS} (db-partition-number
[TO db-partition-number] , ...)]}

2。Not Logged Initially Option

当用create talbe 或者alter talbe 语句带上这个选项，表示不对表的insert或者update 记录日志，特别对于导入大量的数据时，而且这些数据很容易重新创建时，这个选项尤其有用。

3。BLK_LOG_DSK_FUL 参数

The DBM configuration parameter BLK_LOG_DSK_FUL can be used to prevent "disk full" errors from being generated when DB2 cannot create a new log file in the active log path.

4。提高备份性能的参数PARALLELISM ,BACKBUFSZ

BACKUP DATABASE DB2CERT TO /dev/rmt0
       WITH 2 BUFFERS
       BUFFER 512
       PARALLELISM 2

This command backs up the database DB2CERT to a tape device on an AIX system. Two buffers of 512 (4 KB) pages each are allocated. Two parallel tasks are used to backup in parallel

The value of the PARALLELISM parameter. Using this parameter can reduce the amount of time required to complete the backup. It defines the number of processes or threads that are started to read data from the database. Each process or thread is assigned to back up a specific table space. When it completes backing up the table space, it requests another. Increasing the value requires additional processor and memory resources. The default value is one.
The backup buffer size and number of buffers. If you use multiple buffers and I/O channels, you should use at least twice as many buffers as channels to ensure that the channels do not have to wait for data. The size of the buffers should ideally be a multiple of the table space extent size. If you have differing extent sizes, choose a multiple of the largest extent size. If the buffer size if not specified the value is taken from the database manager configuration parameter BACKBUFSZ, which by default is 1024 (4 KB) pages.

5。备份到磁盘上的文件名

SAMPLE.0.db2inst1.NODE0000.CATN0000.20050705103703.001

Database alias - A one to eight character database alias name that was supplied when the backup command was invoked.

Type - Type of backup taken, where: "0" is for full database, "3" is for table space.

Instance name - A one to eight character name of the instance.

Node number - The node number.

Catalog node number - The node number of the database's catalog node.

Time stamp - A 14-character representation of the date and time the backup was performed. The timestamp is in the format yyyymmddhhmmss, where:

yyyy is the year (1995 to 9999), mm is the month (01 to 12),
dd is the day of the month (01 to 31), hh is the hour (00 to 23),
mm is the minutes (00 to 59), ss is the seconds (00 to 59).

Sequence number - A three-digit sequence number used as a file extension.

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