4 - filter(("OPERATION"<>'D' OR "OPERATION" IS NULL) AND ("STARTSCN"<=12723378743688 OR "STARTSCN"
IS NULL) AND "ENDSCN">12723378743688 AND "ENDSCN"<=12723378801092)
5 - filter("STARTSCN"<=12723378743688 OR "STARTSCN" IS NULL)
8 - filter("T"."VERSIONS_STARTSCN" IS NULL)
9 - access("RID"(+)=ROWIDTOCHAR("T".ROWID))
filter("RID"(+)=ROWIDTOCHAR("T".ROWID))
10 - filter(("ENDSCN"(+) IS NULL OR "ENDSCN"(+)>12723378801092) AND ("STARTSCN"(+)<12723378801092 OR
"STARTSCN"(+) IS NULL))
29 rows selected.
2、如果flashback archive被purge了，那么flashback query还是会通过SYS_FBT系列表访问before-image
SQL> explain plan for select * from t0516_7 as of scn 12723393908514;
Explained.
SQL> set pagesize 100 linesize 150
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------
Plan hash value: 4190489988
----------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
----------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 5 | 80 | 21 (10)| 00:00:01 | | |
| 1 | VIEW | | 5 | 80 | 21 (10)| 00:00:01 | | |
| 2 | UNION-ALL | | | | | | | |
| 3 | PARTITION RANGE SINGLE| | 1 | 44 | 14 (0)| 00:00:01 | 1 | 1 |
|* 4 | TABLE ACCESS FULL | SYS_FBA_HIST_549255 | 1 | 44 | 14 (0)| 00:00:01 | 1 | 1 |
|* 5 | FILTER | | | | | | | |
| 6 | MERGE JOIN OUTER | | 4 | 8224 | 7 (29)| 00:00:01 | | |
| 7 | SORT JOIN | | 4 | 112 | 3 (34)| 00:00:01 | | |
|* 8 | TABLE ACCESS FULL | T0516_7 | 4 | 112 | 2 (0)| 00:00:01 | | |
|* 9 | SORT JOIN | | 2 | 4056 | 4 (25)| 00:00:01 | | |
|* 10 | TABLE ACCESS FULL | SYS_FBA_TCRV_549255 | 2 | 4056 | 3 (0)| 00:00:01 | | |
----------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------