Programming - Session

Usage

Dependencies

• JDK >= 1.8
• Maven >= 3.1

How to package only client module

In root directory:

mvn clean package -pl client -am -Dmaven.test.skip=true

How to install in local maven repository

In root directory:

mvn clean install -pl client -am -Dmaven.test.skip=true

Using IoTDB Session with Maven

<dependencies>
    <dependency>
      <groupId>org.apache.iotdb</groupId>
      <artifactId>iotdb-session</artifactId>
      <version>0.9.3</version>
    </dependency>
</dependencies>

Examples with Session interfaces

Here we show the commonly used interfaces and their parameters in the Session:

Run the Session

• Initialize a Session

  Session(String host, int port)

  Session(String host, String port, String username, String password)

  Session(String host, int port, String username, String password)

• Open a Session

  ​ Session.open()

• Close a Session

  ​ Session.close()

Operate the Session

• Set storage group

  ​ TSStatus setStorageGroup(String storageGroupId)

• Delete one or several storage groups

  ​ TSStatus deleteStorageGroup(String storageGroup)

  TSStatus deleteStorageGroups(List<String> storageGroups)

• Create one timeseries under a existing storage group

  ​ TSStatus createTimeseries(String path, TSDataType dataType, TSEncoding encoding, CompressionType compressor)

• Delete one or several timeseries

  ​ TSStatus deleteTimeseries(String path)

  TSStatus deleteTimeseries(List<String> paths)

• Delete one or several timeseries before a certain timestamp

  ​ TSStatus deleteData(String path, long time)

  TSStatus deleteData(List<String> paths, long time)

• Insert data into existing timeseries

  TSStatus insert(String deviceId, long time, List<String> measurements, List<String> values)

• Batch insertion into timeseries

  ​ TSExecuteBatchStatementResp insertBatch(RowBatch rowBatch)

Sample code

To get more information of the following interfaces, please view session/src/main/java/org/apache/iotdb/session/Session.java

The sample code of using these interfaces is in example/session/src/main/java/org/apache/iotdb/SessionExample.java，which provides an example of how to open an IoTDB session, execute a batch insertion.

Session Pool for Native API

We provided a connection pool (`SessionPool) for Native API. Using the interface, you need to define the pool size.

If you can not get a session connection in 60 secondes, there is a warning log but the program will hang.

If a session has finished an operation, it will be put back to the pool automatically. If a session connection is broken, the session will be removed automatically and the pool will try to create a new session and redo the operation.

For query operations:

1. When using SessionPool to query data, the result set is SessionDataSetWrapper;
2. Given a SessionDataSetWrapper, if you have not scanned all the data in it and stop to use it, you have to call SessionPool.closeResultSet(wrapper) manually;
3. When you call hasNext() and next() of a SessionDataSetWrapper and there is an exception, then you have to call SessionPool.closeResultSet(wrapper) manually;

Examples: session/src/test/java/org/apache/iotdb/session/pool/SessionPoolTest.java