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145 lines
6.0 KiB
Markdown
145 lines
6.0 KiB
Markdown
---
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toc_priority: 46
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toc_title: Troubleshooting
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---
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# Troubleshooting {#troubleshooting}
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- [Installation](#troubleshooting-installation-errors)
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- [Connecting to the server](#troubleshooting-accepts-no-connections)
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- [Query processing](#troubleshooting-does-not-process-queries)
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- [Efficiency of query processing](#troubleshooting-too-slow)
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## Installation {#troubleshooting-installation-errors}
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### You Cannot Get Deb Packages from ClickHouse Repository with Apt-get {#you-cannot-get-deb-packages-from-clickhouse-repository-with-apt-get}
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- Check firewall settings.
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- If you cannot access the repository for any reason, download packages as described in the [Getting started](../getting-started/index.md) article and install them manually using the `sudo dpkg -i <packages>` command. You will also need the `tzdata` package.
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## Connecting to the Server {#troubleshooting-accepts-no-connections}
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Possible issues:
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- The server is not running.
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- Unexpected or wrong configuration parameters.
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### Server Is Not Running {#server-is-not-running}
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**Check if server is runnnig**
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Command:
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``` bash
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$ sudo service clickhouse-server status
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```
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If the server is not running, start it with the command:
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``` bash
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$ sudo service clickhouse-server start
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```
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**Check logs**
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The main log of `clickhouse-server` is in `/var/log/clickhouse-server/clickhouse-server.log` by default.
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If the server started successfully, you should see the strings:
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- `<Information> Application: starting up.` — Server started.
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- `<Information> Application: Ready for connections.` — Server is running and ready for connections.
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If `clickhouse-server` start failed with a configuration error, you should see the `<Error>` string with an error description. For example:
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``` text
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2019.01.11 15:23:25.549505 [ 45 ] {} <Error> ExternalDictionaries: Failed reloading 'event2id' external dictionary: Poco::Exception. Code: 1000, e.code() = 111, e.displayText() = Connection refused, e.what() = Connection refused
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```
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If you don’t see an error at the end of the file, look through the entire file starting from the string:
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``` text
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<Information> Application: starting up.
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```
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If you try to start a second instance of `clickhouse-server` on the server, you see the following log:
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``` text
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2019.01.11 15:25:11.151730 [ 1 ] {} <Information> : Starting ClickHouse 19.1.0 with revision 54413
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2019.01.11 15:25:11.154578 [ 1 ] {} <Information> Application: starting up
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2019.01.11 15:25:11.156361 [ 1 ] {} <Information> StatusFile: Status file ./status already exists - unclean restart. Contents:
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PID: 8510
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Started at: 2019-01-11 15:24:23
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Revision: 54413
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2019.01.11 15:25:11.156673 [ 1 ] {} <Error> Application: DB::Exception: Cannot lock file ./status. Another server instance in same directory is already running.
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2019.01.11 15:25:11.156682 [ 1 ] {} <Information> Application: shutting down
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2019.01.11 15:25:11.156686 [ 1 ] {} <Debug> Application: Uninitializing subsystem: Logging Subsystem
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2019.01.11 15:25:11.156716 [ 2 ] {} <Information> BaseDaemon: Stop SignalListener thread
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```
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**See system.d logs**
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If you don’t find any useful information in `clickhouse-server` logs or there aren’t any logs, you can view `system.d` logs using the command:
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``` bash
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$ sudo journalctl -u clickhouse-server
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```
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**Start clickhouse-server in interactive mode**
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``` bash
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$ sudo -u clickhouse /usr/bin/clickhouse-server --config-file /etc/clickhouse-server/config.xml
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```
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This command starts the server as an interactive app with standard parameters of the autostart script. In this mode `clickhouse-server` prints all the event messages in the console.
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### Configuration Parameters {#configuration-parameters}
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Check:
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- Docker settings.
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If you run ClickHouse in Docker in an IPv6 network, make sure that `network=host` is set.
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- Endpoint settings.
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Check [listen\_host](server-configuration-parameters/settings.md#server_configuration_parameters-listen_host) and [tcp\_port](server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port) settings.
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ClickHouse server accepts localhost connections only by default.
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- HTTP protocol settings.
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Check protocol settings for the HTTP API.
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- Secure connection settings.
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Check:
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- The [tcp\_port\_secure](server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port_secure) setting.
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- Settings for [SSL certificates](server-configuration-parameters/settings.md#server_configuration_parameters-openssl).
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Use proper parameters while connecting. For example, use the `port_secure` parameter with `clickhouse_client`.
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- User settings.
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You might be using the wrong user name or password.
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## Query Processing {#troubleshooting-does-not-process-queries}
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If ClickHouse is not able to process the query, it sends an error description to the client. In the `clickhouse-client` you get a description of the error in the console. If you are using the HTTP interface, ClickHouse sends the error description in the response body. For example:
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``` bash
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$ curl 'http://localhost:8123/' --data-binary "SELECT a"
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Code: 47, e.displayText() = DB::Exception: Unknown identifier: a. Note that there are no tables (FROM clause) in your query, context: required_names: 'a' source_tables: table_aliases: private_aliases: column_aliases: public_columns: 'a' masked_columns: array_join_columns: source_columns: , e.what() = DB::Exception
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```
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If you start `clickhouse-client` with the `stack-trace` parameter, ClickHouse returns the server stack trace with the description of an error.
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You might see a message about a broken connection. In this case, you can repeat the query. If the connection breaks every time you perform the query, check the server logs for errors.
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## Efficiency of Query Processing {#troubleshooting-too-slow}
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If you see that ClickHouse is working too slowly, you need to profile the load on the server resources and network for your queries.
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You can use the clickhouse-benchmark utility to profile queries. It shows the number of queries processed per second, the number of rows processed per second, and percentiles of query processing times.
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