OpenTSDB Line Protocol

    • will be used as the STable name.
    • timestamp is the timestamp of current row of data. The time precision will be determined automatically based on the length of the timestamp. Second and millisecond time precision are supported.
    • value is a metric which must be a numeric value, The corresponding column name is “value”.
    • The last part is the tag set separated by spaces, all tags will be converted to NCHAR type automatically.

    For example:

    1. meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3
    • The child table name is created automatically in a rule to guarantee its uniqueness. But 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 automatically created. 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. Please refer to for more details.
    • Java
    • Python
    • Go
    • Node.js
    • C#
    • C
    1. package com.taos.example;
    3. import com.taosdata.jdbc.SchemalessWriter;
    4. import com.taosdata.jdbc.enums.SchemalessProtocolType;
    5. import com.taosdata.jdbc.enums.SchemalessTimestampType;
    7. import java.sql.Connection;
    8. import java.sql.DriverManager;
    9. import java.sql.SQLException;
    10. import java.sql.Statement;
    12. public class TelnetLineProtocolExample {
    13.     // format: <metric> <timestamp> <value> <tagk_1>=<tagv_1>[ <tagk_n>=<tagv_n>]
    14.     private static String[] lines = { "meters.current 1648432611249 10.3 location=California.SanFrancisco groupid=2",
    15.             "meters.current 1648432611250 12.6 location=California.SanFrancisco groupid=2",
    16.             "meters.current 1648432611249 10.8 location=California.LosAngeles groupid=3",
    17.             "meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3",
    18.             "meters.voltage 1648432611249 219 location=California.SanFrancisco groupid=2",
    19.             "meters.voltage 1648432611250 218 location=California.SanFrancisco groupid=2",
    20.             "meters.voltage 1648432611249 221 location=California.LosAngeles groupid=3",
    21.             "meters.voltage 1648432611250 217 location=California.LosAngeles groupid=3",
    22.     };
    24.     private static Connection getConnection() throws SQLException {
    25.         String jdbcUrl = "jdbc:TAOS://localhost:6030?user=root&password=taosdata";
    26.         return DriverManager.getConnection(jdbcUrl);
    27.     }
    29.     private static void createDatabase(Connection conn) throws SQLException {
    30.         try (Statement stmt = conn.createStatement()) {
    31.             // the default precision is ms (microsecond), but we use us(microsecond) here.
    32.             stmt.execute("CREATE DATABASE IF NOT EXISTS test precision 'us'");
    33.             stmt.execute("USE test");
    34.         }
    35.     }
    37.     public static void main(String[] args) throws SQLException {
    38.         try (Connection conn = getConnection()) {
    39.             createDatabase(conn);
    40.             SchemalessWriter writer = new SchemalessWriter(conn);
    41.             writer.write(lines, SchemalessProtocolType.TELNET, SchemalessTimestampType.NOT_CONFIGURED);
    42.         }
    43.     }
    45. }

    1. package main
    3. import (
    5.     "github.com/taosdata/driver-go/v3/af"
    6. )
    9.     _, err := conn.Exec("CREATE DATABASE test")
    10.     if err != nil {
    11.         panic(err)
    12.     }
    13.     _, err = conn.Exec("USE test")
    14.     if err != nil {
    15.         panic(err)
    16.     }
    17. }
    19. func main() {
    20.     conn, err := af.Open("localhost", "root", "taosdata", "", 6030)
    21.     if err != nil {
    22.         log.Fatalln("fail to connect, err:", err)
    23.     }
    24.     defer conn.Close()
    25.     prepareDatabase(conn)
    26.     var lines = []string{
    27.         "meters.current 1648432611249 10.3 location=California.SanFrancisco groupid=2",
    28.         "meters.current 1648432611250 12.6 location=California.SanFrancisco groupid=2",
    29.         "meters.current 1648432611249 10.8 location=California.LosAngeles groupid=3",
    30.         "meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3",
    31.         "meters.voltage 1648432611249 219 location=California.SanFrancisco groupid=2",
    32.         "meters.voltage 1648432611250 218 location=California.SanFrancisco groupid=2",
    33.         "meters.voltage 1648432611249 221 location=California.LosAngeles groupid=3",
    34.         "meters.voltage 1648432611250 217 location=California.LosAngeles groupid=3",
    35.     }
    37.     err = conn.OpenTSDBInsertTelnetLines(lines)
    38.     if err != nil {
    39.         log.Fatalln("insert error:", err)
    40.     }
    41. }

    view source code

    1. const taos = require("@tdengine/client");
    3. const conn = taos.connect({
    4.   host: "localhost",
    5. });
    7. const cursor = conn.cursor();
    9. function createDatabase() {
    10.   cursor.execute("CREATE DATABASE test");
    11.   cursor.execute("USE test");
    12. }
    14. function insertData() {
    15.   const lines = [
    16.     "meters.current 1648432611249 10.3 location=California.SanFrancisco groupid=2",
    17.     "meters.current 1648432611250 12.6 location=California.SanFrancisco groupid=2",
    18.     "meters.current 1648432611249 10.8 location=California.LosAngeles groupid=3",
    19.     "meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3",
    20.     "meters.voltage 1648432611249 219 location=California.SanFrancisco groupid=2",
    21.     "meters.voltage 1648432611250 218 location=California.SanFrancisco groupid=2",
    22.     "meters.voltage 1648432611249 221 location=California.LosAngeles groupid=3",
    23.     "meters.voltage 1648432611250 217 location=California.LosAngeles groupid=3",
    24.   ];
    25.   cursor.schemalessInsert(
    26.     taos.SCHEMALESS_PROTOCOL.TSDB_SML_TELNET_PROTOCOL,
    27.     taos.SCHEMALESS_PRECISION.TSDB_SML_TIMESTAMP_NOT_CONFIGURED
    29. }
    31. try {
    32.   createDatabase();
    33.   insertData();
    34. } finally {
    35.   cursor.close();
    36.   conn.close();
    37. }

    1. int main() {
    2.   TAOS *taos = taos_connect("localhost", "root", "taosdata", "", 6030);
    3.   if (taos == NULL) {
    4.     printf("failed to connect to server\n");
    5.     exit(EXIT_FAILURE);
    6.   }
    7.   executeSQL(taos, "DROP DATABASE IF EXISTS test");
    8.   executeSQL(taos, "CREATE DATABASE test");
    9.   executeSQL(taos, "USE test");
    10.   char *lines[] = {
    11.       "meters.current 1648432611249 10.3 location=California.SanFrancisco groupid=2",
    12.       "meters.current 1648432611250 12.6 location=California.SanFrancisco groupid=2",
    13.       "meters.current 1648432611249 10.8 location=California.LosAngeles groupid=3",
    14.       "meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3",
    15.       "meters.voltage 1648432611249 219 location=California.SanFrancisco groupid=2",
    16.       "meters.voltage 1648432611250 218 location=California.SanFrancisco groupid=2",
    17.       "meters.voltage 1648432611249 221 location=California.LosAngeles groupid=3",
    18.       "meters.voltage 1648432611250 217 location=California.LosAngeles groupid=3",
    19.   };
    20.   TAOS_RES *res = taos_schemaless_insert(taos, lines, 8, TSDB_SML_TELNET_PROTOCOL, TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
    21.   if (taos_errno(res) != 0) {
    22.     printf("failed to insert schema-less data, reason: %s\n", taos_errstr(res));
    23.   } else {
    24.     int affectedRow = taos_affected_rows(res);
    25.     printf("successfully inserted %d rows\n", affectedRow);
    26.   }
    28.   taos_free_result(res);
    29.   taos_close(taos);
    30.   taos_cleanup();
    31. }
    32. // output:
    33. // successfully inserted 8 rows

    view source code

    2 STables will be created automatically and each STable has 4 rows of data in the above sample code.

    1. taos> use test;
    2. Database changed.
    4. taos> show stables;
    5.               name              |
    6. =================================
    7.  meters.current                 |
    8.  meters.voltage                 |
    9. Query OK, 2 row(s) in set (0.002544s)
    11. taos> select tbname, * from `meters.current`;
    12.              tbname             |           _ts            |           _value           | groupid |            location            |
    13. ==================================================================================================================================
    14.  t_0e7bcfa21a02331c06764f275... | 2022-03-28 09:56:51.249 |              10.800000000 | 3       | California.LosAngeles                |
    15.  t_0e7bcfa21a02331c06764f275... | 2022-03-28 09:56:51.250 |              11.300000000 | 3       | California.LosAngeles                |
    16.  t_7e7b26dd860280242c6492a16... | 2022-03-28 09:56:51.249 |              10.300000000 | 2       | California.SanFrancisco               |
    17.  t_7e7b26dd860280242c6492a16... | 2022-03-28 09:56:51.250 |              12.600000000 | 2       | California.SanFrancisco               |
    18. Query OK, 4 row(s) in set (0.005399s)