TDengine is an open source, high-performance, cloud native [time-series database](https://tdengine.com/tsdb/) optimized for Internet of Things (IoT), Connected Cars, and Industrial IoT. Its code, including its cluster feature is open source under GNU AGPL v3.0. Besides the database engine, it provides [caching](../develop/cache), [stream processing](../develop/stream), [data subscription](../develop/tmq) and other functionalities to reduce the system complexity and cost of development and operation.
TDengine is an open source, high-performance, cloud native [time-series database](https://tdengine.com/tsdb/) optimized for Internet of Things (IoT), Connected Cars, and Industrial IoT. Its code, including its cluster feature is open source under GNU AGPL v3.0. Besides the database engine, it provides [caching](/develop/cache), [stream processing](/develop/stream), [data subscription](/develop/tmq) and other functionalities to reduce the system complexity and cost of development and operation.
This section introduces the major features, competitive advantages, typical use-cases and benchmarks to help you get a high level overview of TDengine.
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@@ -11,21 +11,33 @@ This section introduces the major features, competitive advantages, typical use-
The major features are listed below:
1. While TDengine supports [using SQL to insert](/develop/insert-data/sql-writing), it also supports [Schemaless writing](/reference/schemaless/) just like NoSQL databases. TDengine also supports standard protocols like [InfluxDB LINE](/develop/insert-data/influxdb-line)，[OpenTSDB Telnet](/develop/insert-data/opentsdb-telnet), [OpenTSDB JSON ](/develop/insert-data/opentsdb-json) among others.
2. TDengine supports seamless integration with third-party data collection agents like [Telegraf](/third-party/telegraf)，[Prometheus](/third-party/prometheus)，[StatsD](/third-party/statsd)，[collectd](/third-party/collectd)，[icinga2](/third-party/icinga2), [TCollector](/third-party/tcollector), [EMQX](/third-party/emq-broker), [HiveMQ](/third-party/hive-mq-broker). These agents can write data into TDengine with simple configuration and without a single line of code.
3. Support for [all kinds of queries](/develop/query-data), including aggregation, nested query, downsampling, interpolation and others.
4. Support for [user defined functions](/develop/udf).
5. Support for [caching](/develop/cache). TDengine always saves the last data point in cache, so Redis is not needed in some scenarios.
6. Support for [continuous query](../develop/stream).
7. Support for [data subscription](../develop/tmq) with the capability to specify filter conditions.
8. Support for [cluster](../deployment/), with the capability of increasing processing power by adding more nodes. High availability is supported by replication.
9. Provides an interactive [command-line interface](/reference/taos-shell) for management, maintenance and ad-hoc queries.
10. Provides many ways to [import](/operation/import) and [export](/operation/export) data.
11. Provides [monitoring](/operation/monitor) on running instances of TDengine.
12. Provides [connectors](/reference/connector/) for [C/C++](/reference/connector/cpp), [Java](/reference/connector/java), [Python](/reference/connector/python), [Go](/reference/connector/go), [Rust](/reference/connector/rust), [Node.js](/reference/connector/node) and other programming languages.
13. Provides a [REST API](/reference/rest-api/).
14. Supports seamless integration with [Grafana](/third-party/grafana) for visualization.
15. Supports seamless integration with Google Data Studio.
1. Insert data
* supports [using SQL to insert](/develop/insert-data/sql-writing).
* supports [schemaless writing](/reference/schemaless/) just like NoSQL databases. It also supports standard protocols like [InfluxDB LINE](/develop/insert-data/influxdb-line)，[OpenTSDB Telnet](/develop/insert-data/opentsdb-telnet), [OpenTSDB JSON ](/develop/insert-data/opentsdb-json) among others.
* supports seamless integration with third-party tools like [Telegraf](/third-party/telegraf/), [Prometheus](/third-party/prometheus/), [collectd](/third-party/collectd/), [StatsD](/third-party/statsd/), [TCollector](/third-party/tcollector/) and [icinga2/](/third-party/icinga2/), they can write data into TDengine with simple configuration and without a single line of code.
2. Query data
* supports standard [SQL](/taos-sql/), including nested query.
* supports [time series specific functions](/taos-sql/function/#time-series-extensions) and [time series specific queries](/taos-sql/distinguished), like downsampling, interpolation, cumulated sum, time weighted average, state window, session window and many others.
* supports [user defined functions](/taos-sql/udf).
3.[Caching](/develop/cache/): TDengine always saves the last data point in cache, so Redis is not needed for time-series data processing.
4.[Stream Processing](/develop/stream/): not only is the continuous query is supported, but TDengine also supports even driven stream processing, so Flink or spark is not needed for time-series daata processing.
5.[Data Dubscription](/develop/tmq/): application can subscribe a table or a set of tables. API is the same as Kafka, but you can specify filter conditions.
6. Visualization
* supports seamless integration with [Grafana](/third-party/grafana/) for visualization.
* supports seamless integration with Google Data Studio.
7. Cluster
* supports [cluster](/deployment/) with the capability of increasing processing power by adding more nodes.
* supports [deployment on Kubernetes](/deployment/k8s/)
* supports high availability via data replication.
8. Administration
* provides [monitoring](/operation/monitor) on running instances of TDengine.
* provides many ways to [import](/operation/import) and [export](/operation/export) data.
9. Tools
* provides an interactive [command-line interface](/reference/taos-shell) for management, maintenance and ad-hoc queries.
* provides a tool [taosBenchmark](/reference/taosbenchmark/) for testing the performance of TDengine.
10. Programming
* provides [connectors](/reference/connector/) for [C/C++](/reference/connector/cpp), [Java](/reference/connector/java), [Python](/reference/connector/python), [Go](/reference/connector/go), [Rust](/reference/connector/rust), [Node.js](/reference/connector/node) and other programming languages.
* provides a [REST API](/reference/rest-api/).
For more details on features, please read through the entire documentation.
@@ -30,7 +30,7 @@ The following characters cannot occur in a password: single quotation marks ('),
- Maximum number of columns is 4096. There must be at least 2 columns, and the first column must be timestamp.
- The maximum length of a tag name is 64 bytes
- Maximum number of tags is 128. There must be at least 1 tag. The total length of tag values cannot exceed 16 KB.
- Maximum length of single SQL statement is 1 MB (1048576 bytes). It can be configured in the parameter `maxSQLLength` in the client side, the applicable range is [65480, 1048576].
- Maximum length of single SQL statement is 1 MB (1048576 bytes).
- At most 4096 columns can be returned by `SELECT`. Functions in the query statement constitute columns. An error is returned if the limit is exceeded.
- Maximum numbers of databases, STables, tables are dependent only on the system resources.
description:Install, Uninstall, Start, Stop and Upgrade
---
import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";
TDengine community version provides deb and rpm packages for users to choose from, based on their system environment. The deb package supports Debian, Ubuntu and derivative systems. The rpm package supports CentOS, RHEL, SUSE and derivative systems. Furthermore, a tar.gz package is provided for TDengine Enterprise customers.
This document gives more information about installing, uninstalling, and upgrading TDengine.
## Install
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@@ -56,7 +56,7 @@ Removing taostools (2.1.2) ...
Deb package of TDengine can be uninstalled as below:
```bash
```
$ sudo dpkg -r tdengine
(Reading database ... 137504 files and directories currently installed.)
Removing tdengine (3.0.0.0) ...
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@@ -110,109 +110,57 @@ Start to uninstall taos tools ...
taos tools is uninstalled successfully!
```
</TabItem>
<TabItemlabel="Windows uninstall"value="windows">
Run C:\TDengine\unins000.exe to uninstall TDengine on a Windows system.
</TabItem>
</Tabs>
:::note
- We strongly recommend not to use multiple kinds of installation packages on a single host TDengine.
- After deb package is installed, if the installation directory is removed manually, uninstall or reinstall will not work. This issue can be resolved by using the command below which cleans up TDengine package information. You can then reinstall if needed.
:::info
```bash
$ sudo rm-f /var/lib/dpkg/info/tdengine*
```
- We strongly recommend not to use multiple kinds of installation packages on a single host TDengine. The packages may affect each other and cause errors.
- After rpm package is installed, if the installation directory is removed manually, uninstall or reinstall will not work. This issue can be resolved by using the command below which cleans up TDengine package information. You can then reinstall if needed.
```bash
$ sudo rpm -e--noscripts tdengine
```
- After deb package is installed, if the installation directory is removed manually, uninstall or reinstall will not work. This issue can be resolved by using the command below which cleans up TDengine package information.
:::
```
$ sudo rm -f /var/lib/dpkg/info/tdengine*
```
## Installation Directory
You can then reinstall if needed.
TDengine is installed at /usr/local/taos if successful.
- After rpm package is installed, if the installation directory is removed manually, uninstall or reinstall will not work. This issue can be resolved by using the command below which cleans up TDengine package information.
```bash
$ cd /usr/local/taos
$ ll
$ ll
total 28
drwxr-xr-x 7 root root 4096 Feb 22 09:34 ./
drwxr-xr-x 12 root root 4096 Feb 22 09:34 ../
drwxr-xr-x 2 root root 4096 Feb 22 09:34 bin/
drwxr-xr-x 2 root root 4096 Feb 22 09:34 cfg/
lrwxrwxrwx 1 root root 13 Feb 22 09:34 data -> /var/lib/taos/
drwxr-xr-x 2 root root 4096 Feb 22 09:34 driver/
drwxr-xr-x 10 root root 4096 Feb 22 09:34 examples/
- Configuration directory, data directory, and log directory are created automatically if they don't exist
- The default configuration file is located at /etc/taos/taos.cfg, which is a copy of /usr/local/taos/cfg/taos.cfg
- The default data directory is /var/lib/taos, which is a soft link to /usr/local/taos/data
- The default log directory is /var/log/taos, which is a soft link to /usr/local/taos/log
- The executables at /usr/local/taos/bin are linked to /usr/bin
- The DLL files at /usr/local/taos/driver are linked to /usr/lib
- The header files at /usr/local/taos/include are linked to /usr/include
:::
:::note
Uninstalling and Modifying Files
- When TDengine is uninstalled, the configuration /etc/taos/taos.cfg, data directory /var/lib/taos, log directory /var/log/taos are kept. They can be deleted manually with caution, because data can't be recovered. Please follow data integrity, security, backup or relevant SOPs before deleting any data.
- When reinstalling TDengine, if the default configuration file /etc/taos/taos.cfg exists, it will be kept and the configuration file in the installation package will be renamed to taos.cfg.orig and stored at /usr/local/taos/cfg to be used as configuration sample. Otherwise the configuration file in the installation package will be installed to /etc/taos/taos.cfg and used.
## Start and Stop
Linux system services `systemd`, `systemctl` or `service` are used to start, stop and restart TDengine. The server process of TDengine is `taosd`, which is started automatically after the Linux system is started. System operators can use `systemd`, `systemctl` or `service` to start, stop or restart TDengine server.
For example, if using `systemctl` , the commands to start, stop, restart and check TDengine server are below:
- Start server：`systemctl start taosd`
- Stop server：`systemctl stop taosd`
- Restart server：`systemctl restart taosd`
- Check server status：`systemctl status taosd`
Another component named as `taosAdapter` is to provide HTTP service for TDengine, it should be started and stopped using `systemctl`.
If the server process is OK, the output of `systemctl status` is like below:
```
Active: active (running)
```
Otherwise, the output is as below:
- When reinstalling TDengine, if the default configuration file /etc/taos/taos.cfg exists, it will be kept and the configuration file in the installation package will be renamed to taos.cfg.orig and stored at /usr/local/taos/cfg to be used as configuration sample. Otherwise the configuration file in the installation package will be installed to /etc/taos/taos.cfg and used.
```
Active: inactive (dead)
```
## Upgrade
There are two aspects in upgrade operation: upgrade installation package and upgrade a running server.
To upgrade a package, follow the steps mentioned previously to first uninstall the old version then install the new version.
Upgrading a running server is much more complex. First please check the version number of the old version and the new version. The version number of TDengine consists of 4 sections, only if the first 3 sections match can the old version be upgraded to the new version. The steps of upgrading a running server are as below:
- Stop inserting data
- Make sure all data is persisted to disk
- Make some simple queries (Such as total rows in stables, tables and so on. Note down the values. Follow best practices and relevant SOPs.)
- Stop the cluster of TDengine
- Uninstall old version and install new version
- Start the cluster of TDengine
- Execute simple queries, such as the ones executed prior to installing the new package, to make sure there is no data loss
- Execute simple queries, such as the ones executed prior to installing the new package, to make sure there is no data loss
- Run some simple data insertion statements to make sure the cluster works well
- Restore business services
:::warning
TDengine doesn't guarantee any lower version is compatible with the data generated by a higher version, so it's never recommended to downgrade the version.
| Unit | millisecond or microsecond , depending on time precision |
| Value Range | 10-1000000 |
| Default Value | 10 |
### minIntervalTime
| Attribute | Description |
| ------------- | --------------------------- |
| Applicable | Server Only |
| Meaning | Minimum size of time window |
| Unit | millisecond |
| Value Range | 1-1000000 |
| Default Value | 10 |
:::info
To prevent system resource from being exhausted by multiple concurrent streams, a random delay is applied on each stream automatically. `maxFirstStreamCompDelay` is the maximum delay time before a continuous query is started the first time. `streamCompDelayRatio` is the ratio for calculating delay time, with the size of the time window as base. `maxStreamCompDelay` is the maximum delay time. The actual delay time is a random time not bigger than `maxStreamCompDelay`. If a continuous query fails, `retryStreamComDelay` is the delay time before retrying it, also not bigger than `maxStreamCompDelay`.
