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3#
发表于 2012-5-17 12:11:44
4.16.4 [SQL] Fetch Time (ms)
Time taken to retrieve data from the server.
User Action
Fetch Time might be slow if the network bandwidth is low or if database performance is slow. If you have an Enterprise Manager target instance for the database, you should consult the homepage for the database.
用较小的arraysize模拟 慢速的网络
SQL>
SQL> alter session set events '10046 trace name context forever,level 12';
Session altered.
SQL> set pagesize 9999
SQL> set arraysize 1;
SQL> select * from obj$;
72881 rows selected.
select *
from
obj$
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 36442 0.84 2.47 0 36934 0 72881
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 36444 0.84 2.47 0 36934 0 72881
SQL> set arraysize 5000
SQL> select * from obj$;
72881 rows selected.
select *
from
obj$
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 16 0.08 0.12 0 949 0 72881
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 18 0.08 0.12 0 949 0 72881 |
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