Recursive Calls

Recursive calls is a call(sql statement) that must be completed before the completion of user’s SQL statement. Basically, recursive calls are generated by Oracle internal sql statements to maintain changes to tables for internal processing.

Reasons for Recursive Calls

Recursive calls can be generated due to following reasons:

The recursive calls Oracle metric maintains tables used for internal processing. When Oracle needs to make a change to these tables, it internally generates a SQL statement. These internal SQL statements generate recursive calls.

Oracle MetaLink documents also offer information regarding “OPTIMIZING ORACLE7.1 DATABASE PERFORMANCE” including some great points on the recursive calls metric:

“Recursive Calls : occur because of cache misses and dynamic storage
extension. If the dictionary data is found in cache, a recursive call is not
made and the data is read from cache directly. In general if recursive calls
is greater than 4 per process, the data dictionary cache (described below)
should be optimized and segments should be rebuilt with storage clauses
to have a few large extents. Segments include tables, indexes, rollback
segment, and temporary segments.
Also, Recursive calls should be fewer than user calls (less than one-
tenth). Where there is an imbalance the aim should be to reduce parsing.
review : recursive calls to user calls parse count to user calls. High levels
of recursive sql may also be attributable to significant use of PL/SQL.
For each sql statement in a PL/sql block, on each iteration, there are
recursive calls to do the equivalent of bind and define.”

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