Event:10235 ~~~~~~~~~~~ Version/Use: 7.0 - 10.1.X Check memory manager internal structures. 7.0 - 10.1.X "Check memory manager internal structures" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NOTE: Events should NEVER be set by customers unless advised to do so by Oracle Support Services. Read [NOTE:75713.1] before setting any event. Summary Syntax: ~~~~~~~~~~~~~~~ EVENT="10235 trace name context forever, level LL" (Always comment exactly when and why this event is being set) ** IMPORTANT: Do **NOT** use ALTER SESSION SET EVENTS or ORADEBUG syntax to set this event in sessions. This can cause lots of ORA-600 errors against SGA heaps as not all sessions using the SGA heaps will be using the same event level. This applies to ALL levels except level 65536. Levels: ~~~~~~~ The event being set at all causes certain heap checks to be performed. *** WARNING *********************************************************** *** This event should only EVER be set at the request of Oracle Support. *** It can impact performance on most types of system. *** Level 2 and above can impact latch contention. *** Level 3 and above can have a *SEVERE* impact on performance. ************************************************************************ The bottom 3 bits of the level cause the following checks to occur: ~~~~~ ~~~~~~~~~~~~ Level Description ~~~~~ ~~~~~~~~~~~~ 1 Fast check on heap free (kghfrh) 2 Do 1 AND fill memory with junk on alloc / free 3 Do 2 AND ensure the chunk belongs to given heap on free 4 Do 3 AND make permanent chunks freeable so they can also be checked This level can give rise to increased memory use and can trigger false ORA-4030 and false ORA-4031 errors. Oracle 9205 onwards only: 65536 This is introduced by the diagnostic enhancement in bug 3293155. It is a totally independent bit setting which has minimal impact on performance (unless ORed with other levels). When this is set Oracle tries to keep comments with "permanent" memory allocations which can be useful for memory leak problems if the leaked memory appears to be a leak of "perm" memory. This level can be set/unset dynamically but will only store comments in "perm" memory allocated when the event is set. There are additional values which Oracle Support can use. Description/Steps: ~~~~~~~~~~~~~~~~~~ This event may be used to try to catch HEAP corruption problems closer to when they occur. Typically level 12 is required to get close to the corruption but this can impact performance too much to be useful. Example Output / Interpreting Output: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The event should cause an ORA-600 and heapdump to be produced if an error is detected. Related: ~~~~~~~~
本文转自maclean_007 51CTO博客，原文链接:http://blog.51cto.com/maclean/1276739
