OpenTSDB JSON Protocol

Introduction

A JSON string is used in OpenTSDB JSON to represent one or more rows of data, for example: For example:

[
  {
    "metric": "sys.cpu.nice",
    "timestamp": 1346846400,
    "value": 18,
    "tags": {
      "host": "web01",
      "dc": "lga"
    }
  },
  {
    "metric": "sys.cpu.nice",
    "timestamp": 1346846400,
    "value": 9,
    "tags": {
      "host": "web02",
      "dc": "lga"
    }
  }
]

Similar to OpenTSDB line protocol, metric will be used as the STable name, timestamp is the timestamp to be used, value represents the metric collected, tags are the tag sets.

Please refer to OpenTSDB HTTP API for more details.

note

In JSON protocol, strings will be converted to NCHAR type and numeric values will be converted to double type.
The rule of table name
- The child table name is created automatically in a rule to guarantee its uniqueness.
- You can configure smlAutoChildTableNameDelimiter in taos.cfg to specify a delimiter between tag values as the table names. For example, you set smlAutoChildTableNameDelimiter=- in taos.cfg, when you insert st,t0=cpu1,t1=4 c1=3 1626006833639000000, the child table will be cpu1-4
- You can configure smlChildTableName in taos.cfg to specify a tag value as the table names if the tag value is unique globally. For example, if a tag is called tname and you set smlChildTableName=tname in taos.cfg, when you insert st,tname=cpu1,t1=4 c1=3 1626006833639000000, the child table cpu1 will be created automatically. Note that if multiple rows have the same tname but different tag_set values, the tag_set of the first row is used to create the table and the others are ignored

Examples

package com.taos.example;

import com.taosdata.jdbc.SchemalessWriter;
import com.taosdata.jdbc.enums.SchemalessProtocolType;
import com.taosdata.jdbc.enums.SchemalessTimestampType;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class JSONProtocolExample {
    private static Connection getConnection() throws SQLException {
        String jdbcUrl = "jdbc:TAOS://localhost:6030?user=root&password=taosdata";
        return DriverManager.getConnection(jdbcUrl);
    }

    private static void createDatabase(Connection conn) throws SQLException {
        try (Statement stmt = conn.createStatement()) {
            stmt.execute("CREATE DATABASE IF NOT EXISTS test");
            stmt.execute("USE test");
        }
    }

    private static String getJSONData() {
        return "[{\"metric\": \"meters.current\", \"timestamp\": 1648432611249, \"value\": 10.3, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
                " {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611249, \"value\": 219, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}, " +
                "{\"metric\": \"meters.current\", \"timestamp\": 1648432611250, \"value\": 12.6, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
                " {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611250, \"value\": 221, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}]";
    }

    public static void main(String[] args) throws SQLException {
        try (Connection conn = getConnection()) {
            createDatabase(conn);
            SchemalessWriter writer = new SchemalessWriter(conn);
            String jsonData = getJSONData();
            writer.write(jsonData, SchemalessProtocolType.JSON, SchemalessTimestampType.NOT_CONFIGURED);
        }
    }
}

view source code

import json

import taos
from taos import SmlProtocol, SmlPrecision

lines = [{"metric": "meters.current", "timestamp": 1648432611249, "value": 10.3, "tags": {"location": "California.SanFrancisco", "groupid": 2}},
         {"metric": "meters.voltage", "timestamp": 1648432611249, "value": 219,
          "tags": {"location": "California.LosAngeles", "groupid": 1}},
         {"metric": "meters.current", "timestamp": 1648432611250, "value": 12.6,
          "tags": {"location": "California.SanFrancisco", "groupid": 2}},
         {"metric": "meters.voltage", "timestamp": 1648432611250, "value": 221, "tags": {"location": "California.LosAngeles", "groupid": 1}}]


def get_connection():
    return taos.connect()


def create_database(conn):
    conn.execute("CREATE DATABASE test keep 36500")
    conn.execute("USE test")


def insert_lines(conn):
    global lines
    lines = json.dumps(lines)
    # note: the first parameter must be a list with only one element.
    affected_rows = conn.schemaless_insert(
        [lines], SmlProtocol.JSON_PROTOCOL, SmlPrecision.NOT_CONFIGURED)
    print(affected_rows)  # 4


if __name__ == '__main__':
    connection = get_connection()
    try:
        create_database(connection)
        insert_lines(connection)
    finally:
        connection.close()

view source code

package main

import (
	"log"

	"github.com/taosdata/driver-go/v3/af"
)

func prepareDatabase(conn *af.Connector) {
	_, err := conn.Exec("CREATE DATABASE test")
	if err != nil {
		panic(err)
	}
	_, err = conn.Exec("USE test")
	if err != nil {
		panic(err)
	}
}

func main() {
	conn, err := af.Open("localhost", "root", "taosdata", "", 6030)
	if err != nil {
		log.Fatalln("fail to connect, err:", err)
	}
	defer conn.Close()
	prepareDatabase(conn)

	payload := `[{"metric": "meters.current", "timestamp": 1648432611249, "value": 10.3, "tags": {"location": "California.SanFrancisco", "groupid": 2}},
				{"metric": "meters.voltage", "timestamp": 1648432611249, "value": 219, "tags": {"location": "California.LosAngeles", "groupid": 1}},
				{"metric": "meters.current", "timestamp": 1648432611250, "value": 12.6, "tags": {"location": "California.SanFrancisco", "groupid": 2}},
				{"metric": "meters.voltage", "timestamp": 1648432611250, "value": 221, "tags": {"location": "California.LosAngeles", "groupid": 1}}]`

	err = conn.OpenTSDBInsertJsonPayload(payload)
	if err != nil {
		log.Fatalln("insert error:", err)
	}
}

view source code

const taos = require("@tdengine/client");

const conn = taos.connect({
  host: "localhost",
});

const cursor = conn.cursor();

function createDatabase() {
  cursor.execute("CREATE DATABASE test");
  cursor.execute("USE test");
}

function insertData() {
  const lines = [
    {
      metric: "meters.current",
      timestamp: 1648432611249,
      value: 10.3,
      tags: { location: "California.SanFrancisco", groupid: 2 },
    },
    {
      metric: "meters.voltage",
      timestamp: 1648432611249,
      value: 219,
      tags: { location: "California.LosAngeles", groupid: 1 },
    },
    {
      metric: "meters.current",
      timestamp: 1648432611250,
      value: 12.6,
      tags: { location: "California.SanFrancisco", groupid: 2 },
    },
    {
      metric: "meters.voltage",
      timestamp: 1648432611250,
      value: 221,
      tags: { location: "California.LosAngeles", groupid: 1 },
    },
  ];

  cursor.schemalessInsert(
    [JSON.stringify(lines)],
    taos.SCHEMALESS_PROTOCOL.TSDB_SML_JSON_PROTOCOL,
    taos.SCHEMALESS_PRECISION.TSDB_SML_TIMESTAMP_NOT_CONFIGURED
  );
}

try {
  createDatabase();
  insertData();
} finally {
  cursor.close(); 
  conn.close();
}

view source code

using TDengine.Driver;
using TDengine.Driver.Client;

namespace TDengineExample
{
    internal class OptsJsonExample
    {
        public static void Main(string[] args)
        {
            var builder =
                new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                client.Exec("CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
                client.Exec("use test");
                string[] lines =
                {
                    "[{\"metric\": \"meters.current\", \"timestamp\": 1648432611249, \"value\": 10.3, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
                    " {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611249, \"value\": 219, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}, " +
                    "{\"metric\": \"meters.current\", \"timestamp\": 1648432611250, \"value\": 12.6, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
                    " {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611250, \"value\": 221, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}]"
                };
                client.SchemalessInsert(lines, TDengineSchemalessProtocol.TSDB_SML_JSON_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS, 0, ReqId.GetReqId());
            }
        }
    }
}

view source code

int main() {
  TAOS *taos = taos_connect("localhost", "root", "taosdata", "", 6030);
  if (taos == NULL) {
    printf("failed to connect to server\n");
    exit(EXIT_FAILURE);
  }
  executeSQL(taos, "DROP DATABASE IF EXISTS test");
  executeSQL(taos, "CREATE DATABASE test");
  executeSQL(taos, "USE test");
  char *line =
      "[{\"metric\": \"meters.current\", \"timestamp\": 1648432611249, \"value\": 10.3, \"tags\": {\"location\": "
      "\"California.SanFrancisco\", \"groupid\": 2}},{\"metric\": \"meters.voltage\", \"timestamp\": 1648432611249, "
      "\"value\": 219, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}},{\"metric\": \"meters.current\", "
      "\"timestamp\": 1648432611250, \"value\": 12.6, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": "
      "2}},{\"metric\": \"meters.voltage\", \"timestamp\": 1648432611250, \"value\": 221, \"tags\": {\"location\": "
      "\"California.LosAngeles\", \"groupid\": 1}}]";

  char     *lines[] = {line};
  TAOS_RES *res = taos_schemaless_insert(taos, lines, 1, TSDB_SML_JSON_PROTOCOL, TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
  if (taos_errno(res) != 0) {
    printf("failed to insert schema-less data, reason: %s\n", taos_errstr(res));
  } else {
    int affectedRow = taos_affected_rows(res);
    printf("successfully inserted %d rows\n", affectedRow);
  }
  taos_free_result(res);
  taos_close(taos);
  taos_cleanup();
}
// output:
// successfully inserted 4 rows

view source code

2 STables will be created automatically and each STable has 2 rows of data in the above sample code.

taos> use test;
Database changed.

taos> show stables;
              name              |
=================================
 meters_current                 |
 meters_voltage                 |
Query OK, 2 row(s) in set (0.001954s)

taos> select * from `meters_current`;
           _ts            |           _value           |          groupid          |            location            |
===================================================================================================================
 2022-03-28 09:56:51.249 |              10.300000000 |               2.000000000 | California.SanFrancisco               |
 2022-03-28 09:56:51.250 |              12.600000000 |               2.000000000 | California.SanFrancisco               |
Query OK, 2 row(s) in set (0.004076s)

Query Examples

If you want query the data of "tags": {"location": "California.LosAngeles", "groupid": 1}, here is the query SQL:

SELECT * FROM `meters_current` WHERE location = "California.LosAngeles" AND groupid = 3;

Introduction​

Examples​

Query Examples​

Support and Feedback

Introduction

Examples

Query Examples