Oracle Metric parse count (hard)

Oracle Tips by Burleson Consulting

The Oracle Documentation notes:

"If a session executes an SQL statement that does not exist in the shared pool, then Oracle has to do a hard parse.

The parse count (hard) Oracle metric data item represents the number of hard parses per second during this sample period. A hard parse occurs when a SQL statement has to be loaded into the shared pool. In this case, the Oracle Server has to allocate memory in the shared pool and parse the statement.

Each time a particular SQL cursor is parsed, this count will increase by one. There are certain operations which will cause a SQL cursor to be parsed. Parsing a SQL statement breaks it down into atomic steps which the optimizer will evaluate when generating an execution plan for the cursor."

A high value of hard parses indicates non-reentrant SQL, and my notes include:

AWR Report Load Profile

v$sys_time_model scripts

v$sess_time_model scripts

v$sess_time_model

On Oracle MOSC Forums, a user was wondering why his profile read that, "Hard parses 5 and on parse count (hard) 18568" were different. The responded notified that the reason was because the parse count (hard) metric is, "cumulative since the last database startup. The information in the statspack would just represent the snapshot period. They both represent the number of hard parses but likely for different intervals."

This, and many other Oracle performance metrics are discussed in my book "Oracle Tuning" by Rampant TechPress. You can buy it directly from the publisher and save 30% at this link:

http://www.rampant-books.com/book_1002_oracle_tuning_definitive_reference_2nd_ed.htm

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