In-depth analysis of RMAN-RMAN in memory

RMAN goes deep into parsing-RMANRMAN In the Memory creates some buffers in the memory, and then writes data blocks to the backup through these buffers. Memory utilization is related to the overall size of PGA (sometimes SGA. Memory Buffer

RMAN goes deep into parsing-RMANRMAN In the Memory creates some buffers in the memory, and then writes data blocks to the backup through these buffers. Memory utilization is related to the overall size of PGA (sometimes SGA. Memory Buffer

In-depth analysis of RMAN-RMAN in memory

RMAN creates some buffers in the memory and then writes data blocks to the backup through these buffers. Memory utilization is related to the overall size of PGA (sometimes SGA.

The memory buffer is divided into the input buffer and the output buffer. The input buffer is filled with data blocks that are read from the backup file. The output buffer is filled with data blocks that need to be backed up during memory write operations, once the output buffer is filled up, the content of the output buffer is written to the backup location.

Memory usage of RMAN

In disk backup, the PGA memory space is used as the backup buffer, and the PGA memory space is allocated from the memory space used for Channel processes. If local asynchronous I/O is not configured in the operating system, you can use the DBWR_IO_SLAVES parameter to fill in the input buffer in the memory using the I/O bundle. If the DBWR_IO_SLAVES parameter is set to any non-zero value, RMAN automatically allocates four I/O slaves to coordinate the loading of data blocks in the input buffer. To implement this function, RMAN must use a shared memory area. Therefore, the memory buffer used for disk backup is pushed into the Shared Pool. If a large pool exists, it is pushed into the large pool. If the tape I/O slave is not used, the memory used for the tape output buffer is allocated in the PGA.

View the input buffer of The RMAN backup:

[Oracle @ rh6 ~] $ Rman target/Recovery Manager: Release 11.2.0.1.0-Production on Tue Jun 17 18:30:27 2014 Copyright (c) 1982,200 9, Oracle and/or its affiliates. all rights reserved. connected to target database: PROD (DBID = 239333010) RMAN> backup database; Starting backup at 17-JUN-14allocated channel: ORA_DISK_1channel ORA_DISK_1: SID = 43 device type = DISKchannel ORA_DISK_1: starting full datafile backup setchannel ORA_DISK_1: specifying datafile (s) in backup setinput datafile file number = 00001 name =/u01/app/oracle/oradata/prod/system01.dbfinput datafile file number = 00002 name =/u01/app/oracle/oradata/prod/ sysaux01.dbfinput datafile file number = 00005 name =/u01/app/oracle/oradata/prod/example01.dbfinput datafile file number = 00003 name =/u01/app/oracle/oradata/prod/export datafile file number = 00004 name =/u01/app/oracle/oradata/prod/users01.dbfchannel ORA_DISK_1: starting piece 1 at 17-JUN-14channel ORA_DISK_1: finished piece 1 at 17-JUN-14piece handle =/u01/app/oracle/product/11.2.0/db_1/dbs/04pb386s_1_1 tag = login comment = NONEchannel ORA_DISK_1: backup set complete, elapsed time: 00: 01: 42 channel ORA_DISK_1: starting full datafile backup setchannel ORA_DISK_1: specifying datafile (s) in backup setincluding current control file in backup setincluding current SPFILE in backup setchannel ORA_DISK_1: starting piece 1 at 17-JUN-14channel ORA_DISK_1: finished piece 1 at 17-JUN-14piece handle =/u01/app/oracle/product/11.2.0/db_1/dbs/05pb38a3_1_1 tag = login comment = NONEchannel ORA_DISK_1: backup set complete, elapsed time: 00: 00: 01 Finished backup at 17-jun14 view buffer information: SQL> select set_count, device_type, type, filename, buffer_size, buffer_count, open_time, close_time 2 from v $ backup_async_io 3 * order by set_count, type, open_time, please SET_COUNT fill type filename please specify OPEN_TIME please ---------- --------- please wait ------------ --------- 4 disk aggregate 0 0 0 17-JUN-14 17-JUN-14 4 disk input/u01/app/oracle/oradata/prod/issue 524288 6 17-JUN-14 17-jun14 bf 4 disk input/u01/app/oracle/oradata/prod/sysaux01.db 524288 6 17-JUN-14 17-JUN-14 f 4 disk input/u01/app/oracle/oradata/prod/system01.db 524288 6 17-JUN-14 f 4 disk input/u01/app/oracle/oradata/prod/users01.dbf 524288 6 17-JUN-14 17-JUN-14 4 disk input/u01/app/oracle/oradata/prod/undotbs01.d 524288 6 17-jun14 17-jun14 bf 4 disk output/u01/app/oracle/product/11.2.0/db_1/dbs/1048576 4 17-jun14 04pb386s_1_17 rows selected. elapsed: 00:00:00. 02:32:19 SYS @ prod>

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