2011-02-08 11:06:36.894238 [DEBUG] mod_sofia.c:457 Channel sofia/internal/9999999999999@domain.com hanging up, cause: NORMAL_CLEARING
2011-02-08 11:06:37.018489 [DEBUG] mod_nibblebill.c:433 Attempting to bill at $0.03864 per minute to account 9999999999999
2011-02-08 11:06:37.018489 [INFO] mod_nibblebill.c:485 Beginning new billing on 461772290@12.34.56.78
2011-02-08 11:06:37.018489 [DEBUG] mod_nibblebill.c:491 1 seconds passed since last bill time of 2011-02-08 11:06:35
2011-02-08 11:06:37.018489 [DEBUG] mod_nibblebill.c:498 Billing $0.000874 to 9999999999999 (Call: 461772290@12.34.56.78 / 0.000000 so far)
2011-02-08 11:06:37.018489 [DEBUG] mod_nibblebill.c:321 Doing update query
[UPDATE accounts SET cash=cash-0.000874 WHERE id='9999999999999']
2011-02-08 11:06:37.074740 [DEBUG] mod_nibblebill.c:366 Doing lookup query
[SELECT cash AS nibble_balance FROM accounts WHERE id='9999999999999']
2011-02-08 11:06:37.082844 [DEBUG] mod_nibblebill.c:376 Retrieved current balance for account 9999999999999 (balance = 9.579666)
2011-02-08 11:06:37.082844 [DEBUG] switch_core_state_machine.c:46 sofia/internal/9999999999999@domain.com Standard HANGUP, cause: NORMAL_CLEARING
2011-02-08 11:06:37.082844 [DEBUG] switch_core_state_machine.c:557 (sofia/internal/9999999999999@domain.com) State HANGUP going to sleep
2011-02-08 11:06:37.082844 [DEBUG] switch_core_state_machine.c:351 (sofia/internal/9999999999999@domain.com) State Change CS_HANGUP -> CS_REPORTING
2011-02-08 11:06:37.082844 [DEBUG] switch_core_session.c:1116 Send signal sofia/internal/9999999999999@domain.com [BREAK]
2011-02-08 11:06:37.082844 [DEBUG] switch_core_state_machine.c:320 (sofia/internal/9999999999999@domain.com) Running State Change CS_REPORTING
2011-02-08 11:06:37.082844 [DEBUG] switch_core_state_machine.c:617 (sofia/internal/9999999999999@domain.com) State REPORTING
2011-02-08 11:06:37.082844 [DEBUG] mod_nibblebill.c:433 Attempting to bill at $0.03864 per minute to account 9999999999999
2011-02-08 11:06:37.082844 [DEBUG] mod_nibblebill.c:491 0 seconds passed since last bill time of 2011-02-08 11:06:37
2011-02-08 11:06:37.082844 [DEBUG] mod_nibblebill.c:498 Billing $0.000041 to 9999999999999 (Call: 461772290@12.34.56.78 / 0.000874 so far)
2011-02-08 11:06:37.082844 [DEBUG] mod_nibblebill.c:321 Doing update query
[UPDATE accounts SET cash=cash-0.000041 WHERE id='9999999999999']
2011-02-08 11:06:37.133170 [DEBUG] mod_nibblebill.c:366 Doing lookup query
[SELECT cash AS nibble_balance FROM accounts WHERE id='9999999999999']
2011-02-08 11:06:37.201557 [DEBUG] mod_nibblebill.c:376 Retrieved current balance for account 9999999999999 (balance = 9.579625)

How to avoid duplicate SQL requests with nibblebill ?

Thanks