mco_db_sniffer_ex

RT

Inspects the state of all connections to an existing database and performs recovery if dead connections are detected.

Prototype

    MCO_RET mco_db_sniffer_ex(
        mco_db_h db,
        mco_sniffer_callback_ex_t callback,
        void *user_context,
        mco_sniffer_policy policy
    );

Arguments

Description

This function iterates over database connections or transactions (depending on policy) and invokes the provided callback for each one. The callback should determine whether the connection is dead (e.g., using timeouts, watchdogs, or OS-specific mechanisms).

If the callback returns MCO_S_DEAD_CONNECTION, the sniffer initiates database recovery for that connection according to the specified policy. If the callback returns any other error code, mco_db_sniffer_ex stops immediately and returns that code.

The policy parameter controls the inspection scope:

    typedef enum mco_sniffer_policy {
        MCO_SNIFFER_INSPECT_ACTIVE_CONNECTIONS,  // Check all active connections
        MCO_SNIFFER_INSPECT_ACTIVE_TRANSACTIONS, // Check all active transactions
        MCO_SNIFFER_INSPECT_HUNG_TRANSACTIONS    // Check only long-running/hung transactions
    } mco_sniffer_policy;

The callback must not modify its input parameters. It should return:

• MCO_S_OK — connection is alive,
• MCO_S_DEAD_CONNECTION — connection is dead (triggers recovery),
• any other error code — aborts the sniffer and propagates the error.

Return Codes

Files