parse_calls/executions ratio

In a two node RAC cluster running Oracle 10.2.0.3.0 on RHEL4 (I haven't checked a single node instance) awrrpts are showing a negative execute to parse ratio. This implies to me that there are SQL statements being parsed but not executed. What I am seeing by looking at v$sql and querying parse_calls and executions for sql statements is that for non system users (SYS,SYSMAN, etc.) the number of parse_calls is always greater than the number of executions, in the majority of cases the parse_calls are 1 more than the number of executions and for 5 other statements the difference is > 2.

Is this to be expected? This implies that a statement is being parsed at least once without being executed. Is that necessary for Oracle to determine the execution plan or something else? Am I about to learn something here?

Thanks.

Bill Wagman
Univ. of California at Davis
IET Campus Data Center
wjwagman_at_ucdavis.edu
(530) 754-6208

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