[20171129]rman input memory buffer 4.txt
--//Input Memory Buffers如何测试,不清楚.不过找到一本电子书.摘要如下:
Oracle RMAN 11g Backup and Recovery.pdf
作者:Robert G. Freeman Matthew Hart
页数:689
出版社:Mc graw hill
出版号: ISBN: 978-0-07-162861-7
MHID: 0-07-162861-4
RMAN in Memory P80
RMAN builds buffers in memory through which it streams data blocks for potential backup. This
memory utilization counts against the total size of the PGA and, sometimes, the SGA. There are
two kinds of memory buffers. Input buffers are the buffers that are filled with data blocks read
from files that are being backed up. Output buffers are the buffers that are filled when the
memory-to-memory write occurs to determine whether a particular block needs to be backed up.
When the output buffer is filled, it is written to the backup location. The memory buffers differ
depending on whether you are backing up to or restoring from disk or tape. Figure 2-3 illustrates
input and output buffer allocation. It illustrates a backup of two datafiles being multiplexed into
a single backup set.
Input Memory Buffers
When you are backing up the database, the size and number of input memory buffers depend on
the exact backup command being executed. Primarily, they depend on the number of files being
multiplexed into a single backup. Multiplexing refers to the number of files that will have their
blocks backed up to the same backup piece. To keep the memory allocation within reason, the
following rules are applied to the memory buffer sizes based on the number of files being backed
up together:
■ If the number of files going into the backup set is four or less, then RMAN allocates four
buffers per file at 1MB per buffer. The total will be 16MB or less.
■ If the number of files going into the backup set is greater than four, but no greater than
eight, then each file gets four buffers, each of 512KB. This ensures that the total remains
at 16MB or less.
■ If the number of files being multiplexed is greater than eight, then RMAN allocates four
buffers of size 128KB. This ensures that each file being backed up will account for 512KB
of buffer memory.
--//可以想像如果输入缓存如果全部写入输出缓存,通过输出文件写到备份集中的数据分布,也能猜测出输入缓存大小.
--//我在11g备份9个数据文件在一个备份集合看到的input memory buffer = 512K.而不是128K,而且最后备份t09表空间对应的数据文件.
--//我在10g下重复测试:
1.环境:
SYS@test> @ &r/ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- ----------------------------------------------------------------
x86_64/Linux 2.4.xx 10.2.0.4.0 Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
CREATE TABLESPACE T01 DATAFILE '/mnt/ramdisk/test/T01.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T02 DATAFILE '/mnt/ramdisk/test/T02.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T03 DATAFILE '/mnt/ramdisk/test/T03.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T04 DATAFILE '/mnt/ramdisk/test/T04.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T05 DATAFILE '/mnt/ramdisk/test/T05.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T06 DATAFILE '/mnt/ramdisk/test/T06.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T07 DATAFILE '/mnt/ramdisk/test/T07.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T08 DATAFILE '/mnt/ramdisk/test/T08.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T09 DATAFILE '/mnt/ramdisk/test/T09.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
CREATE TABLESPACE T10 DATAFILE '/mnt/ramdisk/test/T10.dbf' SIZE 6M AUTOEXTEND OFF LOGGING ONLINE EXTENT MANAGEMENT LOCAL AUTOALLOCATE BLOCKSIZE 8K SEGMENT SPACE MANAGEMENT AUTO FLASHBACK ON;
create table t01 tablespace t01 as select rownum id ,lpad('A',32,'A') name from dual connect by level<=1e5;
create table t02 tablespace t02 as select rownum id ,lpad('B',32,'B') name from dual connect by level<=1e5;
create table t03 tablespace t03 as select rownum id ,lpad('C',32,'C') name from dual connect by level<=1e5;
create table t04 tablespace t04 as select rownum id ,lpad('D',32,'D') name from dual connect by level<=1e5;
create table t05 tablespace t05 as select rownum id ,lpad('E',32,'E') name from dual connect by level<=1e5;
create table t06 tablespace t06 as select rownum id ,lpad('F',32,'F') name from dual connect by level<=1e5;
create table t07 tablespace t07 as select rownum id ,lpad('G',32,'G') name from dual connect by level<=1e5;
create table t08 tablespace t08 as select rownum id ,lpad('H',32,'H') name from dual connect by level<=1e5;
create table t09 tablespace t09 as select rownum id ,lpad('I',32,'I') name from dual connect by level<=1e5;
create table t10 tablespace t10 as select rownum id ,lpad('J',32,'J') name from dual connect by level<=1e5;
alter system checkpoint;
alter system checkpoint;
2.测试:
RMAN> CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
new RMAN configuration parameters:
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
new RMAN configuration parameters are successfully stored
RMAN> report schema;
Report of database schema
List of Permanent Datafiles
===========================
File Size(MB) Tablespace RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1 510 SYSTEM *** /mnt/ramdisk/test/system01.dbf
2 350 UNDOTBS1 *** /mnt/ramdisk/test/undotbs01.dbf
3 380 SYSAUX *** /mnt/ramdisk/test/sysaux01.dbf
4 100 USERS *** /mnt/ramdisk/test/users01.dbf
5 100 EXAMPLE *** /mnt/ramdisk/test/example01.dbf
6 15 MSSM *** /mnt/ramdisk/test/mssm01.dbf
7 6 T01 *** /mnt/ramdisk/test/T01.dbf
8 6 T02 *** /mnt/ramdisk/test/T02.dbf
9 6 T03 *** /mnt/ramdisk/test/T03.dbf
10 6 T04 *** /mnt/ramdisk/test/T04.dbf
11 6 T05 *** /mnt/ramdisk/test/T05.dbf
12 6 T06 *** /mnt/ramdisk/test/T06.dbf
13 6 T07 *** /mnt/ramdisk/test/T07.dbf
14 6 T08 *** /mnt/ramdisk/test/T08.dbf
15 6 T09 *** /mnt/ramdisk/test/T09.dbf
16 6 T10 *** /mnt/ramdisk/test/T10.dbf
List of Temporary Files
=======================
File Size(MB) Tablespace Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1 18 TEMP 32767 /mnt/ramdisk/test/test01.dbf
RMAN> backup datafile 7,8,9,10,11,12,13,14,15,16 filesperset 10 format '/home/oracle/backup/t123456789A_%U';
Starting backup at 2017-11-29 10:43:27
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00007 name=/mnt/ramdisk/test/T01.dbf
input datafile fno=00008 name=/mnt/ramdisk/test/T02.dbf
input datafile fno=00009 name=/mnt/ramdisk/test/T03.dbf
input datafile fno=00010 name=/mnt/ramdisk/test/T04.dbf
input datafile fno=00011 name=/mnt/ramdisk/test/T05.dbf
input datafile fno=00012 name=/mnt/ramdisk/test/T06.dbf
input datafile fno=00013 name=/mnt/ramdisk/test/T07.dbf
input datafile fno=00014 name=/mnt/ramdisk/test/T08.dbf
input datafile fno=00015 name=/mnt/ramdisk/test/T09.dbf
input datafile fno=00016 name=/mnt/ramdisk/test/T10.dbf
channel ORA_DISK_1: starting piece 1 at 2017-11-29 10:43:28
channel ORA_DISK_1: finished piece 1 at 2017-11-29 10:43:29
piece handle=/home/oracle/backup/t123456789A_1jskp9ug_1_1 tag=TAG20171129T104327 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2017-11-29 10:43:29
$ strings t123456789A_1jskp9ug_1_1 | egrep "AAAAA|BBBBB|CCCCC|DDDDD|EEEEE|FFFFF|GGGGG|HHHHH|IIIII|JJJJJ" | cut -c11-20 | uniq -c
8430 AAAAAAAAAA
8430 BBBBBBBBBB
8430 CCCCCCCCCC
8430 DDDDDDDDDD
8430 EEEEEEEEEE
8430 FFFFFFFFFF
8430 GGGGGGGGGG
8430 HHHHHHHHHH
10116 AAAAAAAAAA
10116 BBBBBBBBBB
10116 CCCCCCCCCC
10116 DDDDDDDDDD
10116 EEEEEEEEEE
10116 FFFFFFFFFF
10116 GGGGGGGGGG
10116 HHHHHHHHHH
10416 AAAAAAAAAA
10416 BBBBBBBBBB
10416 CCCCCCCCCC
10416 DDDDDDDDDD
10416 EEEEEEEEEE
10416 FFFFFFFFFF
10416 GGGGGGGGGG
10416 HHHHHHHHHH
10752 AAAAAAAAAA
10752 BBBBBBBBBB
10752 CCCCCCCCCC
10752 DDDDDDDDDD
10752 EEEEEEEEEE
10752 FFFFFFFFFF
10752 GGGGGGGGGG
10752 HHHHHHHHHH
10416 AAAAAAAAAA
10416 BBBBBBBBBB
10416 CCCCCCCCCC
10416 DDDDDDDDDD
10416 EEEEEEEEEE
10416 FFFFFFFFFF
10416 GGGGGGGGGG
10416 HHHHHHHHHH
10752 AAAAAAAAAA
10752 BBBBBBBBBB
10752 CCCCCCCCCC
10752 DDDDDDDDDD
10752 EEEEEEEEEE
10752 FFFFFFFFFF
10752 GGGGGGGGGG
10752 HHHHHHHHHH
10416 AAAAAAAAAA
10416 BBBBBBBBBB
10416 CCCCCCCCCC
10416 DDDDDDDDDD
10416 EEEEEEEEEE
10416 FFFFFFFFFF
10416 GGGGGGGGGG
10416 HHHHHHHHHH
10752 AAAAAAAAAA
10752 BBBBBBBBBB
10752 CCCCCCCCCC
10752 DDDDDDDDDD
10752 EEEEEEEEEE
10752 FFFFFFFFFF
10752 GGGGGGGGGG
10752 HHHHHHHHHH
10416 AAAAAAAAAA
10416 BBBBBBBBBB
10416 CCCCCCCCCC
10416 DDDDDDDDDD
10416 EEEEEEEEEE
10416 FFFFFFFFFF
10416 GGGGGGGGGG
10416 HHHHHHHHHH
7534 AAAAAAAAAA
7534 BBBBBBBBBB
7534 CCCCCCCCCC
7534 DDDDDDDDDD
7534 EEEEEEEEEE
7534 FFFFFFFFFF
7534 GGGGGGGGGG
7534 HHHHHHHHHH
--//也是先解决8个,继续.看来我理解错误.
8430 IIIIIIIIII
8430 JJJJJJJJJJ
10116 IIIIIIIIII
10116 JJJJJJJJJJ
10416 IIIIIIIIII
10416 JJJJJJJJJJ
10752 IIIIIIIIII
10752 JJJJJJJJJJ
10416 IIIIIIIIII
10416 JJJJJJJJJJ
10752 IIIIIIIIII
10752 JJJJJJJJJJ
10416 IIIIIIIIII
10416 JJJJJJJJJJ
10752 IIIIIIIIII
10752 JJJJJJJJJJ
10416 IIIIIIIIII
10416 JJJJJJJJJJ
7534 IIIIIIIIII
7534 JJJJJJJJJJ
$ strings t123456789A_1jskp9ug_1_1 | egrep "AAAAA|BBBBB|CCCCC|DDDDD|EEEEE|FFFFF|GGGGG|HHHHH|IIIII|JJJJJ" | cut -c11-20 | uniq -c | grep "IIIII"
8430 IIIIIIIIII
10116 IIIIIIIIII
10416 IIIIIIIIII
10752 IIIIIIIIII
10416 IIIIIIIIII
10752 IIIIIIIIII
10416 IIIIIIIIII
10752 IIIIIIIIII
10416 IIIIIIIIII
7534 IIIIIIIIII
$ strings t123456789A_1jskp9ug_1_1 | egrep "AAAAA|BBBBB|CCCCC|DDDDD|EEEEE|FFFFF|GGGGG|HHHHH|IIIII|JJJJJ" | cut -c11-20 | uniq -c | grep "AAAAA"
8430 AAAAAAAAAA
10116 AAAAAAAAAA
10416 AAAAAAAAAA
10752 AAAAAAAAAA
10416 AAAAAAAAAA
10752 AAAAAAAAAA
10416 AAAAAAAAAA
10752 AAAAAAAAAA
10416 AAAAAAAAAA
7534 AAAAAAAAAA
--//备份集合大于8个,先备份8个数据文件,输入缓存512K.继续解决...,如此循环.
--//不过从数量上看读512K(64块)
SYS@test> column PARTITION_NAME noprint
SYS@test> select * from dba_extents where owner=user and segment_name in ('T01');
OWNER SEGMENT_NAME SEGMENT_TYPE TABLESPACE_NAME EXTENT_ID FILE_ID BLOCK_ID BYTES BLOCKS RELATIVE_FNO
------ ------------ ------------ --------------- --------- ------------ ------------ ------------ ------------ ------------
SYS T01 TABLE T01 0 7 9 65536 8 7
SYS T01 TABLE T01 1 7 17 65536 8 7
SYS T01 TABLE T01 2 7 25 65536 8 7
SYS T01 TABLE T01 3 7 33 65536 8 7
SYS T01 TABLE T01 4 7 41 65536 8 7
SYS T01 TABLE T01 5 7 49 65536 8 7
SYS T01 TABLE T01 6 7 57 65536 8 7
SYS T01 TABLE T01 7 7 65 65536 8 7
SYS T01 TABLE T01 8 7 73 65536 8 7
SYS T01 TABLE T01 9 7 81 65536 8 7
SYS T01 TABLE T01 10 7 89 65536 8 7
SYS T01 TABLE T01 11 7 97 65536 8 7
SYS T01 TABLE T01 12 7 105 65536 8 7
SYS T01 TABLE T01 13 7 113 65536 8 7
SYS T01 TABLE T01 14 7 121 65536 8 7
SYS T01 TABLE T01 15 7 129 65536 8 7
SYS T01 TABLE T01 16 7 137 1048576 128 7
SYS T01 TABLE T01 17 7 265 1048576 128 7
SYS T01 TABLE T01 18 7 393 1048576 128 7
SYS T01 TABLE T01 19 7 521 1048576 128 7
20 rows selected.
--//不小心建立schema=sys.
--//不过有1个细节注意10g的前面8块是os,文件头,以及位图区.而11g前面1M是os,文件头,以及位图区.不是正好对齐.
--//也就是 9-63块的内容对于的"AAAA"数量是8430.
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 9 and 63 ;
COUNT(*)
------------
8430
SELECT 'select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between '
|| TO_CHAR (64 + (ROWNUM - 1) * 64)
|| ' and '
|| TO_CHAR (64+ ROWNUM * 64 - 1)
|| ' ;'
c100
FROM DUAL
CONNECT BY LEVEL <= 9;
C100
--------------------------------------------------------------------------------------------
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 64 and 127 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 128 and 191 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 192 and 255 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 256 and 319 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 320 and 383 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 384 and 447 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 448 and 511 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 512 and 575 ;
select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 576 and 639 ;
9 rows selected.
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 64 and 127 ;
COUNT(*)
------------
10116
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 128 and 191 ;
COUNT(*)
------------
10416
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 192 and 255 ;
COUNT(*)
------------
10752
--//不再计算了.
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 512 and 575 ;
COUNT(*)
------------
10416
SYS@test> select count(*) from t01 where DBMS_ROWID.ROWID_BLOCK_NUMBER (rowid) between 576 and 639 ;
COUNT(*)
------------
7534
■ If the number of files being multiplexed is greater than eight, then RMAN allocates four
buffers of size 128KB. This ensures that each file being backed up will account for 512KB
of buffer memory.
--//也就是512K的输入缓存.分配4个每个128K.
--//10个数据文件同时备份到备份集合.
