I am getting two summaries (LIMIT_USAGE_FOR_NS) in debug log. why?

Question

I am getting two summaries in debug log. a small portion of one single log is given below. But i do not know the reason why it is happening?

09:31:34.009 (1009893000)|SYSTEM_METHOD_EXIT|[67]|System.debug(ANY)
09:31:34.013 (1013896000)|METHOD_ENTRY|[1]|01p900000041nyx|ProcessorControl.ProcessorControl()
09:31:34.013 (1013923000)|METHOD_EXIT|[1]|ProcessorControl
09:31:34.014 (1014139000)|SOQL_EXECUTE_BEGIN|[69]|Aggregations:0|select id, SAP_KUNNR__c from account where id = :tmpVar1
09:31:34.020 (1020479000)|SOQL_EXECUTE_END|[69]|Rows:1
09:31:34.020 (1020644000)|DML_BEGIN|[71]|Op:Update|Type:Account|Rows:1
09:31:34.098 (1098297000)|CODE_UNIT_STARTED|[EXTERNAL]|01q9000000082ou|AccountCallout on Account trigger event AfterUpdate for [0019000000s9SiY]
09:31:34.098 (1098561000)|SYSTEM_METHOD_ENTRY|[2]|LIST<Account>.iterator()
09:31:34.098 (1098767000)|SYSTEM_METHOD_EXIT|[2]|LIST<Account>.iterator()
09:31:34.098 (1098790000)|SYSTEM_METHOD_ENTRY|[2]|system.ListIterator.hasNext()
09:31:34.098 (1098807000)|SYSTEM_METHOD_EXIT|[2]|system.ListIterator.hasNext()
09:31:34.098 (1098837000)|SYSTEM_METHOD_ENTRY|[2]|system.ListIterator.hasNext()
09:31:34.098 (1098847000)|SYSTEM_METHOD_EXIT|[2]|system.ListIterator.hasNext()
09:31:34.927 (1098868000)|CUMULATIVE_LIMIT_USAGE
09:31:34.927|LIMIT_USAGE_FOR_NS|(default)|
  Number of SOQL queries: 2 out of 200
  Number of query rows: 2 out of 50000
  Number of SOSL queries: 0 out of 20
  Number of DML statements: 1 out of 150
  Number of DML rows: 1 out of 10000
  Number of code statements: 0 out of 1000000
  Maximum CPU time: 0 out of 60000
  Maximum heap size: 0 out of 12000000
  Number of callouts: 1 out of 10
  Number of Email Invocations: 0 out of 10
  Number of fields describes: 0 out of 100
  Number of record type describes: 0 out of 100
  Number of child relationships describes: 0 out of 100
  Number of picklist describes: 0 out of 100
  Number of future calls: 0 out of 10

09:31:34.927|CUMULATIVE_LIMIT_USAGE_END

09:31:34.098 (1098935000)|CODE_UNIT_FINISHED|AccountCallout on Account trigger event AfterUpdate for [0019000000s9SiY]
09:31:34.103 (1103196000)|DML_END|[71]
09:31:34.103 (1103231000)|SYSTEM_MODE_EXIT|false
09:31:34.931 (1103258000)|CUMULATIVE_LIMIT_USAGE
09:31:34.931|LIMIT_USAGE_FOR_NS|(default)|
  Number of SOQL queries: 2 out of 200
  Number of query rows: 2 out of 50000
  Number of SOSL queries: 0 out of 20
  Number of DML statements: 1 out of 150
  Number of DML rows: 1 out of 10000
  Number of code statements: 0 out of 1000000
  Maximum CPU time: 0 out of 60000
  Maximum heap size: 0 out of 12000000
  Number of callouts: 1 out of 10
  Number of Email Invocations: 0 out of 10
  Number of fields describes: 0 out of 100
  Number of record type describes: 0 out of 100
  Number of child relationships describes: 0 out of 100
  Number of picklist describes: 0 out of 100
  Number of future calls: 0 out of 10

09:31:34.931|CUMULATIVE_LIMIT_USAGE_END

09:31:34.103 (1103281000)|CODE_UNIT_FINISHED|SAPServices.CreateCustomer
09:31:34.103 (1103289000)|EXECUTION_FINISHED

Thanks, Baskaran

Answer 1

The debug log will contain the Cumulative resource usage (the LIMIT_USAGE_FOR_NS event identifer) when a code unit has finished. Note: it will log this information after many code units are finished (a list is contained in the recommended reading below).

My assumption based on the debug log you have posted: on the after update transaction of the Account Trigger, you are performing some code that checks to see if the trigger has been processed, and if not to perform some update on Account. This would cause the after update to fire again, but only to find that it has been processed, and continue on.

This would show as two distinct code units within the debug log, and the cumulative resource usage will be logged after each code unit finishes, since they are triggers.

Recommended Reading: http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_debugging_debug_log.htm