Starting the QDB server

QDB uses the Persistent Publish/Subscribe (PPS) service to dynamically configure databases. Before starting QDB, you must set up PPS. You can then use QDB to load and unload databases.

To set up and use QDB:

Note: The first step is optional and is possible only if you've installed the QNX SDK for Apps and Media. The action described herein improves performance but isn't necessary to successfully use QDB.

  1. In a QNX Neutrino terminal, enter io-fs-media to start the IO service for reading and writing to RAM-based locations.
    Although it's not required, we recommend running your QDB databases in RAM; for example, from a tmpfs filesystem. You can also run databases from locations in QNX filesystems and flash filesystems but performance may suffer with these two filesystem types due to the inherent slowness in writing to the storage media.
  2. Enter pps to start PPS as a background process.
    PPS creates a root directory (/pps by default) to store the PPS configuration objects, which are text files that describe the configuration of QDB databases.
  3. Enter mkdir -p /pps/qnx/qdb to create the directory structure used in the PPS configuration path.
  4. Enter qdb followed by any desired options to start the QDB server.

    For debugging purposes, you should start qdb with -v and -V options to get verbose output. The -v option is cumulative, with each additional v adding a level of verbosity, up to seven levels. The -V option sends output to the console and to the sloginfo log file.

The PPS and QDB server processes are running. You can now add and remove database configuration objects to and from the directory named in the PPS configuration path to dynamically load and unload databases.