NanoMQ Broker

The system configuration provides settings to control the number of task queue threads, the maximum number of concurrent tasks, and cache settings in the NanoMQ broker.

Task Queue

Example Configuration

system {
    num_taskq_thread = 0  # Use a specified number of task queue threads
    max_taskq_thread = 0  # Use a specified maximum number of task queue threads
    parallel = 0          # Handle a specified maximum number of outstanding requests
}

Configuration Item

• num_taskq_thread: Specifies the number of task queue threads to use. The acceptable range is between 1 and 255. If the value is set to 0, the system automatically determines the number of threads.
• max_taskq_thread: Specifies the maximum number of task queue threads to use. The acceptable range is between 1 and 255. If the value is set to 0, the system automatically determines the maximum number of threads.
• parallel: Specifies the maximum number of outstanding requests that the system can handle at once. The acceptable range is between 1 and 255. If the value is set to 0, the system automatically determines the number of parallel tasks.

Cache

NanoMQ uses SQLite to implement the caching for MQTT data bridges.

Example Configuration

sqlite {
    disk_cache_size = 102400  # Max message limitation for caching
    mounted_file_path="/tmp/" # Mounted file path 
    flush_mem_threshold = 100 # The threshold of flushing messages to flash
    resend_interval = 5000    # Resend interval (ms)
}

Configuration Items

• disk_cache_size: Specifies the maximum number of messages that can be cached in the SQLite database; default: 102400; Optional Values:
  • 0: Ineffecitve
  • 1 - infinity
• mounted_file_path: Specifies the file path where the SQLite database file is mounted; default: nanomq running path
• flush_mem_threshold: Specifies the threshold for flushing messages to the SQLite database. When the number of messages reaches this threshold, they are flushed to the SQLite database; default: 100, Value range: 1-infinity
• resend_interval: Specifies the interval, in milliseconds, for resending the messages after a failure is recovered. This is unrelated to the trigger for the resend operation; default: 5000. Note: Only work for the NanoMQ broker to resend cached messages to local client, not for bridging connections.