Comments
| Explain Plan Usage - A quick guide to using AUTOTRACE and EXPLAIN PLAN. |
ravi said... good |
Good Document said... Good |
Ddddd said... hi not so good not working very bad |
Tim... said... Hi.It works fine. You must have made a mistake. Cheers Tim... |
Ashok said... Really nice article.can u tell how to tune stored procedures. |
Tim... said... Please ask questions in the forum!Cheers Tim... |
Craig said... There is a TRACEONLY option on AUTOTRACE that will display the explain plan without running the query, e.g.:set autotrace traceonly explain -Craig |
Tim... said... This is a common assumption, but it is not correct. The TRACEONLY option just supresses the output of the query data. It does not stop the query being run. This example will prove it:CREATE OR REPLACE FUNCTION pause_for_secs(p_seconds IN NUMBER) RETURN NUMBER AS BEGIN DBMS_LOCK.sleep(p_seconds); RETURN p_seconds; END; / SET TIMING ON SET AUTOTRACE ON SELECT pause_for_secs(10) FROM DUAL; SET AUTOTRACE TRACEONLY SELECT pause_for_secs(10) FROM DUAL; Both queries take the same time to return (about 10 seconds). If the second were actually not run, you would expect it to return instantly, like an EXPLAIN PLAN. Cheers Tim... |
Tim... said... I've added this example to the article to make it clear to others.Cheers Tim... |
Chriss said... A good paper which give start information upon what it possible to do. People then may go on every topic to have more information and samples.Many thanks to the author. |
sk said... the article is nice but detail explanation of the concepts would be appreciated |
steve said... Tim,The query isn't run if you use: set autotrace traceonly explain It is run if you use: set autotrace traceonly (as your response to Craig does) Use set autotrace traceonly *explain* <== !!!! ^^^^^^^^^ Steve |
Tim... said... Sure. I'll add it. :)This is an old article and I've not been near it since the 8i days. :) Cheers Tim... |
DO NOT ask technical questions here, that's what my forum is for!
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