mco_db_sniffer

RT

Inspect the state of all connections to an existing database.

Prototype

 
    MCO_RET	mco_db_sniffer(	/*IN*/ mco_db_h db,
                  /*IN*/ mco_sniffer_callback_t callback,
                  /*IN*/ mco_sniffer_policy policy );
 

Arguments

Description

This function inspects the state of all connections to the database using the provided user's callback function. It performs database recovery if dead connections were detected. The callback user defined function must implement logic (using OS, timeout, watchdogs,...) to detect dead database connections. If this callback returns MCO_S_DEAD_CONNECTION then recovery of the database will be performed according to the sniffer policy specified.

The following enum defines the sniffer policy (i.e. when sniffer should call the user-defined callback to check the status of the connection):

 
    typedef enum mco_sniffer_policy {
        MCO_SNIFFER_INSPECT_ACTIVE_CONNECTIONS,
        MCO_SNIFFER_INSPECT_ACTIVE_TRANSACTIONS,
        MCO_SNIFFER_INSPECT_HUNG_TRANSACTIONS
    } mco_sniffer_policy;

 

Nothing should be done to affect the input parameters, and the function should return MCO_S_DEAD_CONNECTION to force database recovery or MCO_S_OK if the connection is ok; any other return code will cause mco_db_sniffer() to interrupt and return this error code.

Return Codes

Example

The example code demonstrating how to use this function is too long to include here. Please refer to the SDK sample "samples/native/core/19-recovery/sniffer".

Files