RE: Reduce parsing

The 'parse calls' statistic is count of how many times the client program calls the database 'PARSE()' call. The *only* way to reduce that, is to modify your client program to make fewer parse calls.

It's possible to reduce the impact of each parse call, by setting 'session_cached_cursors' to a reasonable number, perhaps 50 or 100, and possibly 'cursor_space_for_time=true', but this will NOT change the parse calls statistic.

As to why parse calls is 2x the executions, the following is pure speculation, since I'm not a VB programmer.

In an ideal world, the program would parse each SQL just once, and then execute as many times as needed, possibly binding new values to bind variables before each call. This is what PL/SQL does. Many applications will parse once per execution. This is not uncommon for clients such as SQL*Plus, for example. The really bad programs do things like parse a statement to see if the database connection is alive, or to validate that a dynamically generated SQL is syntactically correct, and then parse again to execute. I've even seen/heard of code that parses a SQL and then NEVER executes it. So, anyhow, you end up with 2 parses/execution. However, sometimes, depending on the language, and the library used for Oracle communication, it's possible to disable the SQL syntactic check or the database connection check, which would drop the number of parses from 2x executions to equal to executions. What the exact root cause is in VB, and whether or not it can be disabled, I have no idea.

Hope that helps,

-Mark

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tracy Rahmlow Sent: Friday, March 20, 2009 5:09 PM
To: oracle-l_at_freelists.org
Subject: Reduce parsing

The following was identified within v$sql in a 10.2.0.4 database -

SQL> select parse_calls, executions, sql_text, module from v$sql   2 where sql_text like '%INTADM.MASK_DATA(:V%'   3 and module = 'POLDOC.EXE';

PARSE_CALLS EXECUTIONS
----------- ----------

SQL_TEXT

     206855 103410
begin :V00001 := INTADM.MASK_DATA(:V00002,:V00003,:V00004); end; POLDOC.EXE The referenced object is a function that is parsed 2x more than it is executed. This is generated from a VB application. We have other function calls that behave similarly (i.e., 2:1 parse to execute). What would cause this statement to be parsed more than executed? Are there any options (other than removing the call) to reduce the number of parse calls relative to the executions?

Thanks

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http://www.freelists.org/webpage/oracle-l Received on Fri Mar 20 2009 - 16:32:05 CDT