Frequently Asked Questions

    • Frequently Asked Questions
      • How can I identify my version of IoTDB?
      • Where can I find IoTDB logs?
      • How do I know how many time series are stored in IoTDB?
      • Can I use Hadoop and Spark to read TsFile in IoTDB?
      • How does IoTDB handle duplicate points?
      • How can I tell what type of the specific timeseries?
      • How can I change IoTDB’s Cli time display format?

    How can I identify my version of IoTDB?

    • Launch IoTDB’s Command Line Interface:
    • Check pom.xml file:
    • Use JDBC API:
    1. String iotdbVersion = tsfileDatabaseMetadata.getDatabaseProductVersion();
    • Use Command Line Interface:
    1. IoTDB> show version
    2. +---------------+
    3. |version        |
    4. +---------------+
    5. |x.x.x          |
    6. +---------------+
    7. Total line number = 1

    Where can I find IoTDB logs?

    Suppose your root directory is:

    Let $IOTDB_HOME = /workspace/incubator-iotdb/server/target/iotdb-server-{project.version}

    Let $IOTDB_CLI_HOME = /workspace/incubator-iotdb/cli/target/iotdb-cli-{project.version}

    By default settings, the logs are stored under IOTDB_HOME/logs. You can change log level and storage path by configuring logback.xml under IOTDB_HOME/conf.

    How do I know how many time series are stored in IoTDB?

    Use IoTDB’s Command Line Interface:

    1. IoTDB> show timeseries root

    In the result, there will be a statement shows Total timeseries number, this number is the timeseries number in IoTDB.

    In the current version, IoTDB supports querying the number of time series. Use IoTDB’s Command Line Interface:

    1. IoTDB> count timeseries root

    If you are using Linux, you can use the following shell command:

    2. >   6

    Can I use Hadoop and Spark to read TsFile in IoTDB?

    A data point is uniquely identified by a full time series path (e.g. root.vehicle.d0.s0) and timestamp. If you submit a new point with the same path and timestamp as an existing point, IoTDB will update the value of this point instead of inserting a new point.

    How can I tell what type of the specific timeseries?

    Use SHOW TIMESERIES <timeseries path> SQL in IoTDB’s Command Line Interface:

    For example, if you want to know the type of all timeseries, the should be root. The statement will be:

    If you want to query specific sensor, you can replace the with the sensor name. For example:

    1. IoTDB> show timeseries root.fit.d1.s1

      How can I change IoTDB’s Cli time display format?

      The default IoTDB’s Cli time display format is human readable (e.g. 1970-01-01T08:00:00.001), if you want to display time in timestamp type or other readable format, add parameter -disableIS08601 in start command:

      1. > $IOTDB_CLI_HOME/sbin/start-cli.sh -h 127.0.0.1 -p 6667 -u root -pw root -disableIS08601