- 对于嵌套查询，仅当内层查询会输出隐式时间戳列时有效。例如select elapsed(ts) from (select diff(value) from sub1)语句，diff函数会让内层查询输出隐式时间戳列，此为主键列，可以用于elapsed函数的第一个参数。相反，例如select elapsed(ts) from (select * from sub1) 语句，ts列输出到外层时已经没有了主键列的含义，无法使用elapsed函数。此外，elapsed函数作为一个与时间线强依赖的函数，形如select elapsed(ts) from (select diff(value) from st group by tbname)尽管会返回一条计算结果，但并无实际意义，这种用法后续也将被限制。
@@ -12,6 +12,6 @@ Between two major release versions, some beta versions may be delivered for user
...
@@ -12,6 +12,6 @@ Between two major release versions, some beta versions may be delivered for user
For the details please refer to [Install and Uninstall](/operation/pkg-install)。
For the details please refer to [Install and Uninstall](/operation/pkg-install)。
To see the details of versions, please refer to [Download List](https://www.taosdata.com/all-downloads) and [Release Notes](https://github.com/taosdata/TDengine/releases).
To see the details of versions, please refer to [Download List](https://tdengine.com/all-downloads) and [Release Notes](https://github.com/taosdata/TDengine/releases).
**Description**：`elapsed` function can be used to calculate the continuous time length in which there is valid data. If it's used with `INTERVAL` clause, the returned result is the calcualted time length within each time window. If it's used without `INTERVAL` caluse, the returned result is the calculated time length within the specified time range. Please be noted that the return value of `elapsed` is the number of `time_unit` in the calculated time length.
**Return value type**：Double
**Applicable Column type**：Timestamp
**Applicable versions**：Sicne version 2.6.0.0
**Applicable tables**: table, STable, outter in nested query
**Explanations**：
-`field_name` parameter can only be the first column of a table, i.e. timestamp primary key.
- The minimum value of `time_unit` is the time precision of the database. If `time_unit` is not specified, the time precision of the database is used as the default ime unit.
- It can be used with `INTERVAL` to get the time valid time length of each time window. Please be noted that the return value is same as the time window for all time windows except for the first and the last time window.
-`order by asc/desc` has no effect on the result.
-`group by tbname` must be used together when `elapsed` is used against a STable.
-`group by` must NOT be used together when `elapsed` is used against a table or sub table.
- When used in nested query, it's only applicable when the inner query outputs an implicit timestamp column as the primary key. For example, `select elapsed(ts) from (select diff(value) from sub1)` is legal usage while `select elapsed(ts) from (select * from sub1)` is not.
- It can't be used with `leastsquares`, `diff`, `derivative`, `top`, `bottom`, `last_row`, `interp`.
## Selection Functions
## Selection Functions
When any select function is used, timestamp column or tag columns including `tbname` can be specified to show that the selected value are from which rows.
When any select function is used, timestamp column or tag columns including `tbname` can be specified to show that the selected value are from which rows.
C/C++ developers can use TDengine's client driver and the C/C++ connector, to develop their applications to connect to TDengine clusters for data writing, querying, and other functions. To use it, you need to include the TDengine header file _taos.h_, which lists the function prototypes of the provided APIs; the application also needs to link to the corresponding dynamic libraries on the platform where it is located.
C/C++ developers can use TDengine's client driver and the C/C++ connector, to develop their applications to connect to TDengine clusters for data writing, querying, and other functions. To use the C/C++ connector you must include the TDengine header file _taos.h_, which lists the function prototypes of the provided APIs. The application also needs to link to the corresponding dynamic libraries on the platform where it is located.
```c
```c
#include <taos.h>
#include <taos.h>
...
@@ -26,7 +26,7 @@ Please refer to [list of supported platforms](/reference/connector#supported-pla
...
@@ -26,7 +26,7 @@ Please refer to [list of supported platforms](/reference/connector#supported-pla
## Supported versions
## Supported versions
The version number of the TDengine client driver and the version number of the TDengine server require one-to-one correspondence and recommend using the same version of client driver as what the TDengine server version is. Although a lower version of the client driver is compatible to work with a higher version of the server, if the first three version numbers are the same (i.e., only the fourth version number is different), but it is not recommended. It is strongly discouraged to use a higher version of the client driver to access a lower version of the TDengine server.
The version number of the TDengine client driver and the version number of the TDengine server should be the same. A lower version of the client driver is compatible with a higher version of the server, if the first three version numbers are the same (i.e., only the fourth version number is different). For e.g. if the client version is x.y.z.1 and the server version is x.y.z.2 the client and server are compatible. But in general we do not recommend using a lower client version with a newer server version. It is also strongly discouraged to use a higher version of the client driver to access a lower version of the TDengine server.
## Installation steps
## Installation steps
...
@@ -55,7 +55,7 @@ In the above example code, `taos_connect()` establishes a connection to port 603
...
@@ -55,7 +55,7 @@ In the above example code, `taos_connect()` establishes a connection to port 603
:::note
:::note
- If not specified, when the return value of the API is an integer, _0_ means success, the others are error codes representing the reason for failure, and when the return value is a pointer, _NULL_ means failure.
- If not specified, when the return value of the API is an integer, _0_ means success. All others are error codes representing the reason for failure. When the return value is a pointer, _NULL_ means failure.
- All error codes and their corresponding causes are described in the `taoserror.h` file.
- All error codes and their corresponding causes are described in the `taoserror.h` file.
:::
:::
...
@@ -140,13 +140,12 @@ The base API is used to do things like create database connections and provide a
...
@@ -140,13 +140,12 @@ The base API is used to do things like create database connections and provide a
- `void taos_cleanup()`
- `void taos_cleanup()`
Clean up the runtime environment and should be called before the application exits.
Cleans up the runtime environment and should be called before the application exits.
Set client options, currently supports region setting (`TSDB_OPTION_LOCALE`), character set
Set client options, currently supports region setting (`TSDB_OPTION_LOCALE`), character set
(`TSDB_OPTION_CHARSET`), time zone
(`TSDB_OPTION_CHARSET`), time zone (`TSDB_OPTION_TIMEZONE`), configuration file path (`TSDB_OPTION_CONFIGDIR`). The region setting, character set, and time zone default to the current settings of the operating system.
(`TSDB_OPTION_TIMEZONE`), configuration file path (`TSDB_OPTION_CONFIGDIR`) . The region setting, character set, and time zone default to the current settings of the operating system.
- `char *taos_get_client_info()`
- `char *taos_get_client_info()`
...
@@ -159,7 +158,7 @@ The base API is used to do things like create database connections and provide a
...
@@ -159,7 +158,7 @@ The base API is used to do things like create database connections and provide a
- host: FQDN of any node in the TDengine cluster
- host: FQDN of any node in the TDengine cluster
- user: user name
- user: user name
- pass: password
- pass: password
- db: database name, if the user does not provide, it can also be connected correctly, the user can create a new database through this connection, if the user provides the database name, it means that the database user has already created, the default use of the database
- db: the database name. Even if the user does not provide this, the connection will still work correctly. The user can create a new database through this connection. If the user provides the database name, it means that the database has already been created and the connection can be used for regular operations on the database.
- port: the port the taosd program is listening on
- port: the port the taosd program is listening on
NULL indicates a failure. The application needs to save the returned parameters for subsequent use.
NULL indicates a failure. The application needs to save the returned parameters for subsequent use.
...
@@ -187,7 +186,7 @@ The APIs described in this subsection are all synchronous interfaces. After bein
...
@@ -187,7 +186,7 @@ The APIs described in this subsection are all synchronous interfaces. After bein
Executes an SQL command, either a DQL, DML, or DDL statement. The `taos` parameter is a handle obtained with `taos_connect()`. You can't tell if the result failed by whether the return value is `NULL`, but by parsing the error code in the result set with the `taos_errno()` function.
Executes an SQL command, either a DQL, DML, or DDL statement. The `taos` parameter is a handle obtained with `taos_connect()`. If the return value is `NULL` this does not necessarily indicate a failure. You can get the error code, if any, by parsing the error code in the result set with the `taos_errno()` function.
- `int taos_result_precision(TAOS_RES *res)`
- `int taos_result_precision(TAOS_RES *res)`
...
@@ -231,7 +230,7 @@ typedef struct taosField {
...
@@ -231,7 +230,7 @@ typedef struct taosField {
- ` void taos_free_result(TAOS_RES *res)`
- ` void taos_free_result(TAOS_RES *res)`
Frees the query result set and the associated resources. Be sure to call this API to free the resources after the query is completed. Otherwise, it may lead to a memory leak in the application. However, note that the application will crash if you call a function like `taos_consume()` to get the query results after freeing the resources.
Frees the query result set and the associated resources. Be sure to call this API to free the resources after the query is completed. Failing to call this, may lead to a memory leak in the application. However, note that the application will crash if you call a function like `taos_consume()` to get the query results after freeing the resources.
- `char *taos_errstr(TAOS_RES *res)`
- `char *taos_errstr(TAOS_RES *res)`
...
@@ -242,7 +241,7 @@ typedef struct taosField {
...
@@ -242,7 +241,7 @@ typedef struct taosField {
Get the reason for the last API call failure. The return value is the error code.
Get the reason for the last API call failure. The return value is the error code.
:::note
:::note
TDengine version 2.0 and above recommends that each thread of a database application create a separate connection or a connection pool based on threads. It is not recommended to pass the connection (TAOS\*) structure to different threads for shared use in the application. Queries, writes, etc., issued based on TAOS structures are multi-thread safe, but state quantities such as "USE statement" may interfere between threads. In addition, the C connector can dynamically create new database-oriented connections on demand (this procedure is not visible to the user), and it is recommended that `taos_close()` be called only at the final exit of the program to close the connection.
TDengine version 2.0 and above recommends that each thread of a database application create a separate connection or a connection pool based on threads. It is not recommended to pass the connection (TAOS\*) structure to different threads for shared use in the application. Queries, writes, and other operations issued that are based on TAOS structures are multi-thread safe, but state quantities such as the "USE statement" may interfere between threads. In addition, the C connector can dynamically create new database-oriented connections on demand (this procedure is not visible to the user), and it is recommended that `taos_close()` be called only at the final exit of the program to close the connection.
:::
:::
...
@@ -274,12 +273,12 @@ All TDengine's asynchronous APIs use a non-blocking call pattern. Applications c
...
@@ -274,12 +273,12 @@ All TDengine's asynchronous APIs use a non-blocking call pattern. Applications c
### Parameter Binding API
### Parameter Binding API
In addition to direct calls to `taos_query()` to perform queries, TDengine also provides a set of `bind` APIs that supports parameter binding, similar in style to MySQL, and currently only supports using a question mark `? ` to represent the parameter to be bound.
In addition to direct calls to `taos_query()` to perform queries, TDengine also provides a set of `bind` APIs that supports parameter binding, similar in style to MySQL. TDengine currently only supports using a question mark `? ` to represent the parameter to be bound.
Starting with versions 2.1.1.0 and 2.1.2.0, TDengine has significantly improved the bind APIs to support for data writing (INSERT) scenarios. This avoids the resource consumption of SQL syntax parsing when writing data through the parameter binding interface, thus significantly improving write performance in most cases. A typical operation, in this case, is as follows.
Starting with versions 2.1.1.0 and 2.1.2.0, TDengine has significantly improved the bind APIs to support data writing (INSERT) scenarios. This avoids the resource consumption of SQL syntax parsing when writing data through the parameter binding interface, thus significantly improving write performance in most cases. A typical operation, in this case, is as follows.
1. call `taos_stmt_init()` to create the parameter binding object.
1. call `taos_stmt_init()` to create the parameter binding object.
2. call `taos_stmt_prepare()` to parse the INSERT statement. 3.
2. call `taos_stmt_prepare()` to parse the INSERT statement.
3. call `taos_stmt_set_tbname()` to set the table name if it is reserved in the INSERT statement but not the TAGS.
3. call `taos_stmt_set_tbname()` to set the table name if it is reserved in the INSERT statement but not the TAGS.
4. call `taos_stmt_set_tbname_tags()` to set the table name and TAGS values if the table name and TAGS are reserved in the INSERT statement (for example, if the INSERT statement takes an automatic table build).
4. call `taos_stmt_set_tbname_tags()` to set the table name and TAGS values if the table name and TAGS are reserved in the INSERT statement (for example, if the INSERT statement takes an automatic table build).
5. call `taos_stmt_bind_param_batch()` to set the value of VALUES in multiple columns, or call `taos_stmt_bind_param()` to set the value of VALUES in a single row.
5. call `taos_stmt_bind_param_batch()` to set the value of VALUES in multiple columns, or call `taos_stmt_bind_param()` to set the value of VALUES in a single row.
...
@@ -383,7 +382,7 @@ In addition to writing data using the SQL method or the parameter binding API, w
...
@@ -383,7 +382,7 @@ In addition to writing data using the SQL method or the parameter binding API, w
**return value**
**return value**
TAOS_RES structure, application can get error message by using `taos_errstr()` and also error code by using `taos_errno()`.
TAOS_RES structure, application can get error message by using `taos_errstr()` and also error code by using `taos_errno()`.
In some cases, the returned TAOS_RES is `NULL`, and it is still possible to call `taos_errno()` to safely get the error code information.
In some cases, the returned TAOS_RES is `NULL`, and it is still possible to call `taos_errno()` to safely get the error code information.
The returned TAOS_RES needs to be freed by the caller. Otherwise, a memory leak will occur.
The returned TAOS_RES needs to be freed by the caller in order to avoid memory leaks.
**Description**
**Description**
The protocol type is enumerated and contains the following three formats.
The protocol type is enumerated and contains the following three formats.
...
@@ -416,13 +415,13 @@ The Subscription API currently supports subscribing to one or more tables and co
...
@@ -416,13 +415,13 @@ The Subscription API currently supports subscribing to one or more tables and co
This function is responsible for starting the subscription service, returning the subscription object on success and `NULL` on failure, with the following parameters.
This function is responsible for starting the subscription service, returning the subscription object on success and `NULL` on failure, with the following parameters.
- taos: the database connection that has been established
- taos: the database connection that has been established.
- restart: if the subscription already exists, whether to restart or continue the previous subscription
- restart: if the subscription already exists, whether to restart or continue the previous subscription.
- topic: the topic of the subscription (i.e., the name). This parameter is the unique identifier of the subscription
- topic: the topic of the subscription (i.e., the name). This parameter is the unique identifier of the subscription.
- sql: the query statement of the subscription, this statement can only be _select_ statement, only the original data should be queried, only the data can be queried in time order
- sql: the query statement of the subscription which can only be a _select_ statement. Only the original data should be queried, and data can only be queried in temporal order.
- fp: the callback function when the query result is received (the function prototype will be introduced later), only used when called asynchronously. This parameter should be passed `NULL` when called synchronously
- fp: the callback function when the query result is received only used when called asynchronously. This parameter should be passed `NULL` when called synchronously. The function prototype is described below.
- param: additional parameter when calling the callback function, the system API will pass it to the callback function as it is, without any processing
- param: additional parameter when calling the callback function. The system API will pass it to the callback function as is, without any processing.
- interval: polling period in milliseconds. The callback function will be called periodically according to this parameter when called asynchronously. not recommended to set this parameter too small To avoid impact on system performance when called synchronously. If the interval between two calls to `taos_consume()` is less than this period, the API will block until the interval exceeds this period.
- interval: polling period in milliseconds. The callback function will be called periodically according to this parameter when called asynchronously. The interval should not be too small to avoid impact on system performance when called synchronously. If the interval between two calls to `taos_consume()` is less than this period, the API will block until the interval exceeds this period.
1. "Unable to establish connection", "Unable to resolve FQDN"
1. "Unable to establish connection", "Unable to resolve FQDN"
Usually, it cause by the FQDN configuration is incorrect, you can refer to [How to understand TDengine's FQDN (Chinese)](https://www.taosdata.com/blog/2021/07/29/2741.html) to solve it.
Usually, it's caused by an incorrect FQDN configuration. Please refer to this section in the [FAQ](https://docs.tdengine.com/2.4/train-faq/faq/#2-how-to-handle-unable-to-establish-connection) to troubleshoot.
2. Unhandled exception. System.DllNotFoundException: Unable to load DLL 'taos' or one of its dependencies: The specified module cannot be found.
2. Unhandled exception. System.DllNotFoundException: Unable to load DLL 'taos' or one of its dependencies: The specified module cannot be found.
@@ -225,7 +225,7 @@ See [video tutorial](https://www.taosdata.com/blog/2020/11/11/1957.html) for the
...
@@ -225,7 +225,7 @@ See [video tutorial](https://www.taosdata.com/blog/2020/11/11/1957.html) for the
2. "Unable to establish connection", "Unable to resolve FQDN"
2. "Unable to establish connection", "Unable to resolve FQDN"
Usually, root cause is the FQDN is not configured correctly. You can refer to [How to understand TDengine's FQDN (In Chinese)](https://www.taosdata.com/blog/2021/07/29/2741.html).
Usually, the root cause is an incorrect FQDN configuration. You can refer to this section in the [FAQ](https://docs.tdengine.com/2.4/train-faq/faq/#2-how-to-handle-unable-to-establish-connection) to troubleshoot.
@@ -7,7 +7,7 @@ TDengine Kafka Connector contains two plugins: TDengine Source Connector and TDe
...
@@ -7,7 +7,7 @@ TDengine Kafka Connector contains two plugins: TDengine Source Connector and TDe
## What is Kafka Connect?
## What is Kafka Connect?
Kafka Connect is a component of Apache Kafka that enables other systems, such as databases, cloud services, file systems, etc., to connect to Kafka easily. Data can flow from other software to Kafka via Kafka Connect and Kafka to other systems via Kafka Connect. Plugins that read data from other software are called Source Connectors, and plugins that write data to other software are called Sink Connectors. Neither Source Connector nor Sink Connector will directly connect to Kafka Broker, and Source Connector transfers data to Kafka Connect. Sink Connector receives data from Kafka Connect.
Kafka Connect is a component of [Apache Kafka](https://kafka.apache.org/) that enables other systems, such as databases, cloud services, file systems, etc., to connect to Kafka easily. Data can flow from other software to Kafka via Kafka Connect and Kafka to other systems via Kafka Connect. Plugins that read data from other software are called Source Connectors, and plugins that write data to other software are called Sink Connectors. Neither Source Connector nor Sink Connector will directly connect to Kafka Broker, and Source Connector transfers data to Kafka Connect. Sink Connector receives data from Kafka Connect.
The above script first clones the project source code and then compiles and packages it with Maven. After the package is complete, the zip package of the plugin is generated in the `target/components/packages/` directory. Unzip this zip package to the path where the plugin is installed. The path to install the plugin is in the configuration file `$CONFLUENT_HOME/etc/kafka/connect-standalone.properties`. The default path is `$CONFLUENT_HOME/share/confluent-hub-components/`.
The above script first clones the project source code and then compiles and packages it with Maven. After the package is complete, the zip package of the plugin is generated in the `target/components/packages/` directory. Unzip this zip package to plugin path. We used `$CONFLUENT_HOME/share/java/` above because it's a build in plugin path.
### Install with confluent-hub
### Install with confluent-hub
...
@@ -96,7 +96,7 @@ confluent local services start
...
@@ -96,7 +96,7 @@ confluent local services start
```
```
:::note
:::note
Be sure to install the plugin before starting Confluent. Otherwise, there will be a class not found error. The log of Kafka Connect (default path: /tmp/confluent.xxxx/connect/logs/connect.log) will output the successfully installed plugin, which users can use to determine whether the plugin is installed successfully.
Be sure to install the plugin before starting Confluent. Otherwise, Kafka Connect will fail to discover the plugins.
:::
:::
:::tip
:::tip
...
@@ -123,6 +123,59 @@ Control Center is [UP]
...
@@ -123,6 +123,59 @@ Control Center is [UP]
To clear data, execute `rm -rf /tmp/confluent.106668`.
To clear data, execute `rm -rf /tmp/confluent.106668`.
:::
:::
### Check Confluent Services Status
Use command bellow to check the status of all service:
```
confluent local services status
```
The expected output is:
```
Connect is [UP]
Control Center is [UP]
Kafka is [UP]
Kafka REST is [UP]
ksqlDB Server is [UP]
Schema Registry is [UP]
ZooKeeper is [UP]
```
### Check Successfully Loaded Plugin
After Kafka Connect was completely started, you can use bellow command to check if our plugins are installed successfully:
```
confluent local services connect plugin list
```
The output should contains `TDengineSinkConnector` and `TDengineSourceConnector` as bellow:
It should produce a path like:`/tmp/confluent.104086/connect/connect.stdout`
Besides log file `connect.stdout` there is a file named `connect.properties`. At the end of this file you can see the effective `plugin.path` which is a series of paths joined by comma. If Kafka Connect not found our plugins, it's probably because the installed path is not included in `plugin.path`.
## The use of TDengine Sink Connector
## The use of TDengine Sink Connector
The role of the TDengine Sink Connector is to synchronize the data of the specified topic to TDengine. Users do not need to create databases and super tables in advance. The name of the target database can be specified manually (see the configuration parameter connection.database), or it can be generated according to specific rules (see the configuration parameter connection.database.prefix).
The role of the TDengine Sink Connector is to synchronize the data of the specified topic to TDengine. Users do not need to create databases and super tables in advance. The name of the target database can be specified manually (see the configuration parameter connection.database), or it can be generated according to specific rules (see the configuration parameter connection.database.prefix).
@@ -356,6 +411,7 @@ The following configuration items apply to TDengine Sink Connector and TDengine
...
@@ -356,6 +411,7 @@ The following configuration items apply to TDengine Sink Connector and TDengine
4.`max.retries`: The maximum number of retries when an error occurs. Defaults to 1.
4.`max.retries`: The maximum number of retries when an error occurs. Defaults to 1.
5.`retry.backoff.ms`: The time interval for retry when sending an error. The unit is milliseconds. The default is 3000.
5.`retry.backoff.ms`: The time interval for retry when sending an error. The unit is milliseconds. The default is 3000.
6.`db.schemaless`: Data format, could be one of `line`, `json`, and `telnet`. Represent InfluxDB line protocol format, OpenTSDB JSON format, and OpenTSDB Telnet line protocol format.
6.`db.schemaless`: Data format, could be one of `line`, `json`, and `telnet`. Represent InfluxDB line protocol format, OpenTSDB JSON format, and OpenTSDB Telnet line protocol format.
7.`data.precision`: The time precision when use InfluxDB line protocol format data, could be one of `ms`, `us` and `ns`. The default is `ns`.
### TDengine Source Connector specific configuration
### TDengine Source Connector specific configuration
...
@@ -366,7 +422,13 @@ The following configuration items apply to TDengine Sink Connector and TDengine
...
@@ -366,7 +422,13 @@ The following configuration items apply to TDengine Sink Connector and TDengine
5.`fetch.max.rows`: The maximum number of rows retrieved when retrieving the database. Default is 100.
5.`fetch.max.rows`: The maximum number of rows retrieved when retrieving the database. Default is 100.
6.`out.format`: The data format. The value could be line or json. The line represents the InfluxDB Line protocol format, and json represents the OpenTSDB JSON format. Default is `line`.
6.`out.format`: The data format. The value could be line or json. The line represents the InfluxDB Line protocol format, and json represents the OpenTSDB JSON format. Default is `line`.
## feedback
## Other notes
1. To install plugin to a customized location, refer to https://docs.confluent.io/home/connect/self-managed/install.html#install-connector-manually.
2. To use Kafka Connect without confluent, refer to https://kafka.apache.org/documentation/#connect.
If the tips in FAQ don't help much, please submit an issue on [GitHub](https://github.com/taosdata/TDengine) to describe your problem description, including TDengine version, hardware and OS information, the steps to reproduce the problem, etc. It would be very helpful if you package the contents in `/var/log/taos` and `/etc/taos` and upload. These two are the default directories used by TDengine, if they have been changed in your configuration, please use according to the actual configuration. It's recommended to firstly set `debugFlag` to 135 in `taos.cfg`, restart `taosd`, then reproduce the problem and collect logs. If you don't want to restart, an alternative way of setting `debugFlag` is executing `alter dnode <dnode_id> debugFlag 135` command in TDengine CLI `taos`. During normal running, however, please make sure `debugFlag` is set to 131.
If the tips in FAQ don't help much, please submit an issue on [GitHub](https://github.com/taosdata/TDengine) to describe your problem. In your description please include the TDengine version, hardware and OS information, the steps to reproduce the problem and any other relevant information. It would be very helpful if you can package the contents in `/var/log/taos` and `/etc/taos` and upload. These two are the default directories used by TDengine. If you have changed the default directories in your configuration, please package the files in your configured directories. We recommended setting `debugFlag` to 135 in `taos.cfg`, restarting `taosd`, then reproducing the problem and collecting the logs. If you don't want to restart, an alternative way of setting `debugFlag` is executing `alter dnode <dnode_id> debugFlag 135` command in TDengine CLI `taos`. During normal running, however, please make sure `debugFlag` is set to 131.
## Frequently Asked Questions
## Frequently Asked Questions
### 1. How to upgrade to TDengine 2.0 from older version?
### 1. How to upgrade to TDengine 2.0 from older version?
version 2.x is not compatible with version 1.x regarding configuration file and data file, please do following before upgrading:
version 2.x is not compatible with version 1.x. With regard to the configuration and data files, please perform the following steps before upgrading. Please follow data integrity, security, backup and other relevant SOPs, best practices before removing/deleting any data.
3. Delete data files if the data doesn't need to be kept: `sudo rm -rf /var/lib/taos/`
3. Delete data files if the data doesn't need to be kept: `sudo rm -rf /var/lib/taos/`
4. Install latests 2.x version
4. Install latest 2.x version
5. If the data needs to be kept and migrated to newer version, please contact professional service of TDengine for assistance
5. If the data needs to be kept and migrated to newer version, please contact professional service at TDengine for assistance.
### 2. How to handle "Unable to establish connection"？
### 2. How to handle "Unable to establish connection"？
When the client is unable to connect to the server, you can try following ways to find out why.
When the client is unable to connect to the server, you can try the following ways to troubleshoot and resolve the problem.
1. Check the network
1. Check the network
- Check if the hosts where the client and server are running can be accessible to each other, for example by `ping` command.
- Check if the hosts where the client and server are running are accessible to each other, for example by `ping` command.
- Check if the TCP/UDP on port 6030-6042 are open for access if firewall is enabled. It's better to firstly disable firewall for diagnostics.
- Check if the TCP/UDP on port 6030-6042 are open for access if firewall is enabled. If possible, disable the firewall for diagnostics, but please ensure that you are following security and other relevant protocols.
- Check if the FQDN and serverPort are configured correctly in `taos.cfg` used by the server side
- Check if the FQDN and serverPort are configured correctly in `taos.cfg` used by the server side.
- Check if the `firstEp` is set properly in the `taos.cfg` used by the client side
- Check if the `firstEp` is set properly in the `taos.cfg` used by the client side.
2. Make sure the client version and server version are same.
2. Make sure the client version and server version are same.
3. On server side, check the running status of `taosd` by executing `systemctl status taosd` . If your server is started using another way instead of `systemctl`, use the proper method to check whether the server process is running normally.
3. On server side, check the running status of `taosd` by executing `systemctl status taosd` . If your server is started using another way instead of `systemctl`, use the proper method to check whether the server process is running normally.
4. If using connector of Python, Java, Go, Rust, C#, node.JS on Linux to connect toe the server, please make sure `libtaos.so` is in directory `/usr/local/taos/driver` and `/usr/local/taos/driver` is in system lib search environment variable `LD_LIBRARY_PATH`.
4. If using connector of Python, Java, Go, Rust, C#, node.JS on Linux to connect to the server, please make sure `libtaos.so` is in directory `/usr/local/taos/driver` and `/usr/local/taos/driver` is in system lib search environment variable `LD_LIBRARY_PATH`.
5. If using connector on Windows, please make sure `C:\TDengine\driver\taos.dll` is in your system lib search path, it's suggested to put`taos.dll` under `C:\Windows\System32`.
5. If using connector on Windows, please make sure `C:\TDengine\driver\taos.dll` is in your system lib search path. We recommend putting`taos.dll` under `C:\Windows\System32`.
6. Some advanced network diagnostics tools
6. Some advanced network diagnostics tools
...
@@ -45,7 +45,7 @@ When the client is unable to connect to the server, you can try following ways t
...
@@ -45,7 +45,7 @@ When the client is unable to connect to the server, you can try following ways t
Check whether a TCP port on server side is open: `nc -l {port}`
Check whether a TCP port on server side is open: `nc -l {port}`
Check whether a TCP port on client side is open: `nc {hostIP} {port}`
Check whether a TCP port on client side is open: `nc {hostIP} {port}`
- On Windows system `Net-TestConnection -ComputerName {fqdn} -Port {port}` on PowerShell can be used to check whether the port on serer side is open for access.
- On Windows system `Net-TestConnection -ComputerName {fqdn} -Port {port}` on PowerShell can be used to check whether the port on server side is open for access.
7. TDengine CLI `taos` can also be used to check network, please refer to [TDengine CLI](/reference/taos-shell).
7. TDengine CLI `taos` can also be used to check network, please refer to [TDengine CLI](/reference/taos-shell).
@@ -3,15 +3,15 @@ sidebar_label: TDengine in Docker
...
@@ -3,15 +3,15 @@ sidebar_label: TDengine in Docker
title:Deploy TDengine in Docker
title:Deploy TDengine in Docker
---
---
Even though it's not recommended to deploy TDengine using docker in production system, docker is still very useful in development environment, especially when your host is not Linux. From version 2.0.14.0, the official image of TDengine can support X86-64, X86, arm64, and rm32 .
We do not recommend deploying TDengine using Docker in a production system. However, Docker is still very useful in a development environment, especially when your host is not Linux. From version 2.0.14.0, the official image of TDengine can support X86-64, X86, arm64, and rm32 .
In this chapter a simple step by step guide of using TDengine in docker is introduced.
In this chapter we introduce a simple step by step guide to use TDengine in Docker.
## Install Docker
## Install Docker
The installation of docker please refer to [Get Docker](https://docs.docker.com/get-docker/).
To install Docker please refer to [Get Docker](https://docs.docker.com/get-docker/).
After docker is installed, you can check whether Docker is installed properly by displaying Docker version.
After Docker is installed, you can check whether Docker is installed properly by displaying Docker version.
In the above command, a docker container is started to run TDengine server, the port range 6030-6049 of the container is mapped to host port range 6030-6049. If port range 6030-6049 has been occupied on the host, please change to an available host port range. Regarding the requirements about ports on the host, please refer to [Port Configuration](/reference/config/#serverport).
In the above command, a docker container is started to run TDengine server, the port range 6030-6049 of the container is mapped to host port range 6030-6049. If port range 6030-6049 has been occupied on the host, please change to an available host port range. For port requirements on the host, please refer to [Port Configuration](/reference/config/#serverport).
-**docker run**: Launch a docker container
-**docker run**: Launch a docker container
-**-d**: the container will run in background mode
-**-d**: the container will run in background mode
...
@@ -95,7 +95,7 @@ In TDengine CLI, SQL commands can be executed to create/drop databases, tables,
...
@@ -95,7 +95,7 @@ In TDengine CLI, SQL commands can be executed to create/drop databases, tables,
### Access TDengine from host
### Access TDengine from host
If `-p` used to map ports properly between host and container, it's also able to access TDengine in container from the host as long as `firstEp` is configured correctly for the client on host.
If option `-p` used to map ports properly between host and container, it's also able to access TDengine in container from the host as long as `firstEp` is configured correctly for the client on host.
```
```
$ taos
$ taos
...
@@ -271,7 +271,7 @@ Below is an example output:
...
@@ -271,7 +271,7 @@ Below is an example output:
### Access TDengine from 3rd party tools
### Access TDengine from 3rd party tools
A lot of 3rd party tools can be used to write data into TDengine through `taosAdapter`, for details please refer to [3rd party tools](/third-party/).
A lot of 3rd party tools can be used to write data into TDengine through `taosAdapter`, for details please refer to [3rd party tools](/third-party/).
There is nothing different from the 3rd party side to access TDengine server inside a container, as long as the end point is specified correctly, the end point should be the FQDN and the mapped port of the host.
There is nothing different from the 3rd party side to access TDengine server inside a container, as long as the end point is specified correctly, the end point should be the FQDN and the mapped port of the host.
