Database Reference
In-Depth Information
Because the PL/SQL block wasn't executed by the database recursively, the recursive depth isn't shown
(the recursive depth is 0). Also, no execution plan is available:
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 34 (CHRIS)
The database waits for
SQL*Net message to client
while instructing the network layer to send data to the client
(be careful, the real time needed to send the data over the network isn't included), and the database waits for
SQL*Net
message from client
while waiting for a message from the client. Consequently, for each round-trip carried out
by the SQL*Net layer, you should see a pair of those wait events. Note that the number of round-trips carried out by
lower-level layers might be different. For example, it's not uncommon that at the network layer (for example, IP)
a larger number of round-trips are performed because of a smaller packet size:
Elapsed times include waiting on following events:
Event waited on Times Waited Max. Wait Total Waited
---------------------------------- ------------- ---------- ------------
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.00 0.00
The next SQL statement is the second one that was executed by the PL/SQL block. The structure of the
information is the same as before. What's interesting to point out is that this query was executed ten times. For each
execution, the trace file contains the execution statistics (since level 16 was enabled). As a result, the value of
Number
of plan statistics captured
is 10, the three
Rows
columns contains different values (122, 676 and 1229), and
the runtime statistics at the row source level are averages (for example, 53 disk reads over 10 executions make an
average of 5):
SQL ID: 7fjjjf0yvd05m Plan Hash: 4270555908
SELECT COUNT(N)
FROM
T WHERE ID < :B1 *123
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute
10
0.00 0.00 0 0 0 0
Fetch 10 0.00 0.02 53 303 0 10
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 21 0.01 0.02
53
303 0 10
Misses in library cache during parse: 1
Misses in library cache during execute: 1
Optimizer mode: ALL_ROWS
Parsing user id: 34 (CHRIS) (recursive depth: 1)
Number of plan statistics captured:
10
