揭密一致性读------之UNDO回滚链 - 数据库编程

8 1048576 128 EXPIRED 5 3 8192 1048576 128 EXPIRED 6 3 9600 1048576 128 EXPIRED 7 3 11136 1048576 128 EXPIRED 8 3 12800 1048576 128 EXPIRED 9 3 14208 1048576 128 EXPIRED 10 3 15744 1048576 128 EXPIRED 11 3 17408 1048576 128 EXPIRED 12 3 18688 1048576 128 EXPIRED 13 3 84864 8388608 1024 ACTIVE 14 3 178560 8388608 1024 EXPIRED sys@OCM> select * from v$rollstat; USN LATCH EXTENTS RSSIZE WRITES XACTS GETS WAITS OPTSIZE HWMSIZE SHRINKS WRAPS EXTENDSAVESHRINK AVEACTIVE STATUS CUREXT CURBLK ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- --------------- ---------- ---------- 0 0 6 385024 8112 0 93 0 385024 0 0 0 0 ONLINE 5 4 1 1 16 14802944 1172136 0 832 0 14802944 0 1 00 104857 ONLINE 15 45 2 2 5 3268608 930888 0 871 0 3268608 0 1 00 104857 ONLINE 3 53 3 0 17 2088960 1175554 0 948 0 2088960 0 16 140 123087 ONLINE 14 56 4 1 17 15851520 981912 0 779 0 15851520 0 1 00 104857 ONLINE 16 45 5 2 24 19259392 581992 0 688 0 19259392 0 1 00 104857 ONLINE 23 81 6 0 3 1171456 807088 0 810 0 1171456 0 1 00 104857 ONLINE 0 4 7 1 15 28434432 246082 1 361 0 28434432 0 0 0 0 ONLINE 13 108 8 2 5 3268608 843906 0 789 0 3268608 0 1 00 104857 ONLINE 4 95 9 0 12 10608640 725944 0 775 0 10608640 0 1 00 104857 ONLINE 3 75 10 1 5 2285568 800262 0 727 0 2285568 0 4 00 109093 ONLINE 2 83 ******************************************************************************** Undo Segment: _SYSSMU7_4222772309$ (7) ******************************************************************************** Extent Control Header ----------------------------------------------------------------- Extent Header:: spare1: 0 spare2: 0 #extents: 15 #blocks: 3471 last map 0x00000000 #maps: 0 offset: 4080 Highwater:: 0x00c14bec ext#: 13 blk#: 108 ext size: 1024 #blocks in seg. hdr's freelists: 0 #blocks below: 0 mapblk 0x00000000 offset: 13 Unlocked Map Header:: next 0x00000000 #extents: 15 obj#: 0 flag: 0x40000000 Extent Map ----------------------------------------------------------------- 0x00c000e1 length: 7 0x00c00258 length: 8 0x00c00c80 length: 128 0x00c01380 length: 128 0x00c01980 length: 128 0x00c02000 length: 128 0x00c02580 length: 128 0x00c02b80 length: 128 0x00c03200 length: 128 0x00c03780 length: 128 0x00c03d80 length: 128 0x00c04400 length: 128 0x00c04900 length: 128 0x00c14b80 length: 1024 0x00c2b980 length: 1024 Retention Table -----------------------------------------------------------

揭密一致性读------之UNDO回滚链(二)