Database Reference
In-Depth Information
Rows (1st) Rows (avg) Rows (max) Row Source Operation
---------- ---------- ---------- ---------------------------------------------------
1 1 1 SORT AGGREGATE (cr=30 pr=
5
pw=0 time=2607 us)
122 676 1229
TABLE ACCESS BY INDEX ROWID T (cr=30 pr=5 pw=0 time=2045 us
cost=8 size=1098 card=122)
122 676 1229 INDEX RANGE SCAN T_PK (cr=4 pr=0 pw=0 time=872 us cost=3
size=0 card=122)(object id 20991)
Rows Execution Plan
------- ---------------------------------------------------
0 SELECT STATEMENT MODE: ALL_ROWS
1 SORT (AGGREGATE)
122 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'T' (TABLE)
122 INDEX MODE: ANALYZED (RANGE SCAN) OF 'T_PK' (INDEX (UNIQUE)
)
Elapsed times include waiting on following events:
Event waited on Times Waited Max. Wait Total Waited
----------------------------------- ------------ ---------- ------------
db file sequential read 53 0.00 0.02
The last SQL statement was recursively executed by the database engine in order to get information (for example,
object statistics) about the objects being used. Among other things, the query optimizer uses such information to
figure out the most efficient execution plan. You have confirmation that this SQL statement was executed by the
database engine because the user who parsed it is SYS. Because the recursive depth is 2, you can suppose that this SQL
statement is needed to parse one SQL statement at depth 1—for example, the first SQL statement in this output file:
SQL ID: 96g93hntrzjtr Plan Hash: 2239883476
select /*+ rule */ bucket_cnt, row_cnt, cache_cnt, null_cnt, timestamp#,
sample_size, minimum, maximum, distcnt, lowval, hival, density, col#,
spare1, spare2, avgcln
from
hist_head$ where obj#=:1 and intcol#=:2
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 0 0.00 0.00 0 0 0 0
Execute 4 0.00 0.00 0 0 0 0
Fetch 4 0.00 0.01 5 12 0 4
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 8 0.00 0.01 5 12 0 4
Misses in library cache during parse: 0
Optimizer mode: RULE
Parsing user id: SYS (recursive depth: 2)
