先从Online Move Datafile说起

DATA FILE #12:
name #21: /tmp/12_mvnew.dbf
name #20: /oracle/app/oracle/oradata/ORA12C/B727E6DDCF847CEDE0555D384BFF4A69/datafile/12_mvnew.dbf ( second)
creation size=640 block size=8192 status=0xe flg=0x1 head=21 tail=20 dup=1
pdb_id 3, tablespace 5, index=14 krfil=12 prev_file_in_ts=0 prev_file_in_pdb=11
unrecoverable scn: 0x0000000000000000 01/01/1988 00:00:00
Checkpoint cnt:65 scn: 0x00000000003ff3ff 11/19/2021 22:09:10
Stop scn: 0xffffffffffffffff 11/19/2021 13:51:53
Creation Checkpointed at scn: 0x00000000001608f6 12/24/2020 03:43:36
thread:1 rba:(0x2.1c87f.10)
enabled threads: 01000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x00000000003ddac3 prev_range: 48
Online Checkpointed at scn: 0x00000000003f64d8 11/19/2021 13:54:21
thread:1 rba:(0x24.7b.10)
enabled threads: 01000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000000000000000
aux_file is NOT DEFINED
Plugged readony: NO
Plugin scnscn: 0x0000000000000000
Plugin resetlogs scn/timescn: 0x0000000000000000 01/01/1988 00:00:00
Foreign creation scn/timescn: 0x0000000000000000 01/01/1988 00:00:00
Foreign checkpoint scn/timescn: 0x0000000000000000 01/01/1988 00:00:00
Online move state: 1
查看dbwr持有的句柄发现dbwr持有了secondary file的句柄：
[root@dbtest fd]# ls -l /proc/8355/fd |grep 12_mvnew
lrwx------ 1 oracle oinstall 64 Nov 19 22:51 267 -> /oracle/app/oracle/oradata/ORA12C/B727E6DDCF847CEDE0555D384BFF4A69/datafile/12_mvnew.dbf
lrwx------ 1 oracle oinstall 64 Nov 19 22:51 272 -> /tmp/12_mvnew.dbf
第三步：调用kcffo_mv_copy_loop函数对数据文件其他block进行拷贝，从2号块开始以多块读的方式做数据文件的拷贝。
为什么函数中有loop呢？个人认为是在此过程期间如果数据文件发生自动扩展或者resize，还会调用 kcffo_mv_copy_loop 继续拷贝。
WAIT #140452597414360: nam='db file scattered read' ela= 2723 file#=12 block#=2 blocks=127 obj#=0 tim=64444328091
WAIT #140452597414360: nam='db file parallel write' ela= 2992 requests=12 interrupt=2 timeout=127 obj#=0 tim=64444331227
WAIT #140452597414360: nam='db file scattered read' ela= 2298 file#=12 block#=129 blocks=128 obj#=0 tim=64444333571
WAIT #140452597414360: nam='db file parallel write' ela= 3640 requests=12 interrupt=129 timeout=128 obj#=0 tim=64444337409
WAIT #140452597414360: nam='db file scattered read' ela= 2760 file#=12 block#=257 blocks=128 obj#=0 tim=64444340251
WAIT #140452597414360: nam='db file parallel write' ela= 3509 requests=12 interrupt=257 timeout=128 obj#=0 tim=64444343842
WAIT #140452597414360: nam='db file scattered read' ela= 2507 file#=12 block#=385 blocks=128 obj#=0 tim=64444346388
WAIT #140452597414360: nam='db file parallel write' ela= 3211 requests=12 interrupt=385 timeout=128 obj#=0 tim=64444349715
WAIT #140452597414360: nam='db file scattered read' ela= 2583 file#=12 block#=513 blocks=128 obj#=0 tim=64444352382
WAIT #140452597414360: nam='db file parallel write' ela= 3236 requests=12 interrupt=513 timeout=128 obj#=0 tim=64444355779
WAIT #140452597414360: nam='db file scattered read' ela= 1935 file#=12 block#=641 blocks=128 obj#=0 tim=64444357826
WAIT #140452597414360: nam='db file parallel write' ela= 2767 requests=12 interrupt=641 timeout=128 obj#=0 tim=64444360665
WAIT #140452597414360: nam='db file scattered read' ela= 3931 file#=12 block#=769 blocks=128 obj#=0 tim=64444364681
WAIT #140452597414360: nam='db file parallel write' ela= 2514 requests=12 interrupt=769 timeout=128 obj#=0 tim=64444367978
WAIT #140452597414360: nam='db file scattered read' ela= 2204 file#=12 block#=897 blocks=128 obj#=0 tim=64444370384
WAIT #140452597414360: nam='db file parallel write' ela= 11184 requests=12 interrupt=897 timeout=128 obj#=0 tim=64444382079
WAIT #140452597414360: nam='db file scattered read' ela= 19043 file#=12 block#=1025 blocks=128 obj#=0 tim=64444401178
WAIT #140452597414360: nam='db file parallel write' ela= 2658 requests=12 interrupt=1025 timeout=128 obj#=0 tim=64444404082
...
WAIT #140452576418240: nam='db file scattered read' ela= 6702 file#=12 block#=130817 blocks=128 obj#=0 tim=96033679518
WAIT #140452576418240: nam='db file parallel write' ela= 3469 requests=12 interrupt=130817 timeout=128 obj#=0 tim=96033683562
WAIT #140452576418240: nam='db file scattered read' ela= 3211 file#=12 block#=130945 blocks=128 obj#=0 tim=96033687162
WAIT #140452576418240: nam='db file parallel write' ela= 4810 requests=12 interrupt=130945 timeout=128 obj#=0 tim=96033692734
WAIT #140452576418240: nam='rdbms ipc reply' ela= 1291 from_process=19 p2=0 p3=0 obj#=0 tim=96033694888
WAIT #140452576418240: nam='control file sequential read' ela= 7 file#=0 block#=1 blocks=1 obj#=0 tim=96033695382
WAIT #140452576418240: nam='control file sequential read' ela= 4 file#=1 block#=1 blocks=1 obj#=0 tim=96033695560
WAIT #140452576418240: nam='control file sequential read' ela= 8 file#=0 block#=16 blocks=1 obj#=0 tim=96033695629
WAIT #140452576418240: nam='control file sequential read' ela= 7 file#=0 block#=18 blocks=1 obj#=0 tim=96033695698
WAIT #140452576418240: nam='control file sequential read' ela= 9 file#=0 block#=24 blocks=1 obj#=0 tim=96033695798
WAIT #140452576418240: nam='db file sequential read' ela= 7 file#=12 block#=1 blocks=1 obj#=0 tim=96033695868
kcffo_mv_domove: Blocks copied for file /oracle/app/oracle/oradata/ORA12C/B727E6DDCF847CEDE0555D38