ClickHouse
ClickHouse
Plugin: go.d.plugin Module: clickhouse
Overview
This collector retrieves performance data from ClickHouse for connections, queries, resources, replication, IO, and data operations (inserts, selects, merges) using HTTP requests and ClickHouse system tables. It monitors your ClickHouse server’s health and activity.
It sends HTTP requests to the ClickHouse HTTP interface, executing SELECT queries to retrieve data from various system tables. Specifically, it collects metrics from the following tables:
- system.metrics
- system.async_metrics
- system.events
- system.disks
- system.parts
- system.processes
This collector is supported on all platforms.
This collector supports collecting metrics from multiple instances of this integration, including remote instances.
Default Behavior
Auto-Detection
By default, it detects ClickHouse instances running on localhost that are listening on port 8123. On startup, it tries to collect metrics from:
- http://127.0.0.1:8123
Limits
The default configuration for this integration does not impose any limits on data collection.
Performance Impact
The default configuration for this integration is not expected to impose a significant performance impact on the system.
Setup
Prerequisites
No action required.
Configuration
File
The configuration file name for this integration is go.d/clickhouse.conf.
You can edit the configuration file using the edit-config script from the
Netdata config directory.
cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/clickhouse.conf
Options
The following options can be defined globally: update_every, autodetection_retry.
| Name | Description | Default | Required |
|---|---|---|---|
| update_every | Data collection frequency. | 1 | no |
| autodetection_retry | Recheck interval in seconds. Zero means no recheck will be scheduled. | 0 | no |
| url | Server URL. | http://127.0.0.1:8123 | yes |
| timeout | HTTP request timeout. | 1 | no |
| username | Username for basic HTTP authentication. | no | |
| password | Password for basic HTTP authentication. | no | |
| proxy_url | Proxy URL. | no | |
| proxy_username | Username for proxy basic HTTP authentication. | no | |
| proxy_password | Password for proxy basic HTTP authentication. | no | |
| method | HTTP request method. | GET | no |
| body | HTTP request body. | no | |
| headers | HTTP request headers. | no | |
| not_follow_redirects | Redirect handling policy. Controls whether the client follows redirects. | no | no |
| tls_skip_verify | Server certificate chain and hostname validation policy. Controls whether the client performs this check. | no | no |
| tls_ca | Certification authority that the client uses when verifying the server’s certificates. | no | |
| tls_cert | Client TLS certificate. | no | |
| tls_key | Client TLS key. | no |
Examples
Basic
A basic example configuration.
jobs:
- name: local
url: http://127.0.0.1:8123
HTTP authentication
Basic HTTP authentication.
jobs:
- name: local
url: http://127.0.0.1:8123
username: username
password: password
HTTPS with self-signed certificate
ClickHouse with enabled HTTPS and self-signed certificate.
jobs:
- name: local
url: https://127.0.0.1:8123
tls_skip_verify: yes
Multi-instance
Note: When you define multiple jobs, their names must be unique.
Collecting metrics from local and remote instances.
jobs:
- name: local
url: http://127.0.0.1:8123
- name: remote
url: http://192.0.2.1:8123
Metrics
Metrics grouped by scope.
The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.
Per ClickHouse instance
These metrics refer to the entire monitored application.
This scope has no labels.
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| clickhouse.connections | tcp, http, mysql, postgresql, interserver | connections |
| clickhouse.slow_reads | slow | reads/s |
| clickhouse.read_backoff | read_backoff | events/s |
| clickhouse.memory_usage | used | bytes |
| clickhouse.running_queries | running | queries |
| clickhouse.queries_preempted | preempted | queries |
| clickhouse.queries | successful, failed | queries/s |
| clickhouse.select_queries | successful, failed | selects/s |
| clickhouse.insert_queries | successful, failed | inserts/s |
| clickhouse.queries_memory_limit_exceeded | mem_limit_exceeded | queries/s |
| clickhouse.longest_running_query_time | longest_query_time | seconds |
| clickhouse.queries_latency | queries_time | microseconds |
| clickhouse.select_queries_latency | selects_time | microseconds |
| clickhouse.insert_queries_latency | inserts_time | microseconds |
| clickhouse.io | reads, writes | bytes/s |
| clickhouse.iops | reads, writes | ops/s |
| clickhouse.io_errors | read, write | errors/s |
| clickhouse.io_seeks | lseek | ops/s |
| clickhouse.io_file_opens | file_open | ops/s |
| clickhouse.replicated_parts_current_activity | fetch, send, check | parts |
| clickhouse.replicas_max_absolute_dela | replication_delay | seconds |
| clickhouse.replicated_readonly_tables | read_only | tables |
| clickhouse.replicated_data_loss | data_loss | events |
| clickhouse.replicated_part_fetches | successful, failed | fetches/s |
| clickhouse.inserted_rows | inserted | rows/s |
| clickhouse.inserted_bytes | inserted | bytes/s |
| clickhouse.rejected_inserts | rejected | inserts/s |
| clickhouse.delayed_inserts | delayed | inserts/s |
| clickhouse.delayed_inserts_throttle_time | delayed_inserts_throttle_time | milliseconds |
| clickhouse.selected_bytes | selected | bytes/s |
| clickhouse.selected_rows | selected | rows/s |
| clickhouse.selected_parts | selected | parts/s |
| clickhouse.selected_ranges | selected | ranges/s |
| clickhouse.selected_marks | selected | marks/s |
| clickhouse.merges | merge | ops/s |
| clickhouse.merges_latency | merges_time | milliseconds |
| clickhouse.merged_uncompressed_bytes | merged_uncompressed | bytes/s |
| clickhouse.merged_rows | merged | rows/s |
| clickhouse.merge_tree_data_writer_inserted_rows | inserted | rows/s |
| clickhouse.merge_tree_data_writer_uncompressed_bytes | inserted | bytes/s |
| clickhouse.merge_tree_data_writer_compressed_bytes | written | bytes/s |
| clickhouse.uncompressed_cache_requests | hits, misses | requests/s |
| clickhouse.mark_cache_requests | hits, misses | requests/s |
| clickhouse.max_part_count_for_partition | max_parts_partition | parts |
| clickhouse.parts_count | temporary, pre_active, active, deleting, delete_on_destroy, outdated, wide, compact | parts |
| distributed_connections | active | connections |
| distributed_connections_attempts | connection | attempts/s |
| distributed_connections_fail_retries | connection_retry | fails/s |
| distributed_connections_fail_exhausted_retries | connection_retry_exhausted | fails/s |
| distributed_files_to_insert | pending_insertions | files |
| distributed_rejected_inserts | rejected | inserts/s |
| distributed_delayed_inserts | delayed | inserts/s |
| distributed_delayed_inserts_latency | delayed_time | milliseconds |
| distributed_sync_insertion_timeout_exceeded | sync_insertion | timeouts/s |
| distributed_async_insertions_failures | async_insertions | failures/s |
| clickhouse.uptime | uptime | seconds |
Per disk
These metrics refer to the Disk.
Labels:
| Label | Description |
|---|---|
| disk_name | Name of the disk as defined in the server configuration. |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| clickhouse.disk_space_usage | free, used | bytes |
Per table
These metrics refer to the Database Table.
Labels:
| Label | Description |
|---|---|
| database | Name of the database. |
| table | Name of the table. |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| clickhouse.database_table_size | size | bytes |
| clickhouse.database_table_parts | parts | parts |
| clickhouse.database_table_rows | rows | rows |
Alerts
The following alerts are available:
| Alert name | On metric | Description |
|---|---|---|
| clickhouse_restarted | clickhouse.uptime | ClickHouse has recently been restarted |
| clickhouse_queries_preempted | clickhouse.queries_preempted | ClickHouse has queries that are stopped and waiting due to priority setting |
| clickhouse_long_running_query | clickhouse.longest_running_query_time | ClickHouse has a long-running query exceeding the threshold |
| clickhouse_rejected_inserts | clickhouse.rejected_inserts | ClickHouse has INSERT queries that are rejected due to high number of active data parts for partition in a MergeTree |
| clickhouse_delayed_inserts | clickhouse.delayed_inserts | ClickHouse has INSERT queries that are throttled due to high number of active data parts for partition in a MergeTree |
| clickhouse_replication_lag | clickhouse.replicas_max_absolute_delay | ClickHouse is experiencing replication lag greater than 5 minutes |
| clickhouse_replicated_readonly_tables | clickhouse.replicated_readonly_tables | ClickHouse has replicated tables in readonly state due to ZooKeeper session loss/startup without ZooKeeper configured |
| clickhouse_max_part_count_for_partition | clickhouse.max_part_count_for_partition | ClickHouse high number of parts per partition |
| clickhouse_distributed_connections_failures | clickhouse.distributed_connections_fail_exhausted_retries | ClickHouse has failed distributed connections after exhausting all retry attempts |
| clickhouse_distributed_files_to_insert | clickhouse.distributed_files_to_insert | ClickHouse high number of pending files to process for asynchronous insertion into Distributed tables |
Troubleshooting
Debug Mode
To troubleshoot issues with the clickhouse collector, run the go.d.plugin with the debug option enabled. The output
should give you clues as to why the collector isn’t working.
-
Navigate to the
plugins.ddirectory, usually at/usr/libexec/netdata/plugins.d/. If that’s not the case on your system, opennetdata.confand look for thepluginssetting under[directories].cd /usr/libexec/netdata/plugins.d/ -
Switch to the
netdatauser.sudo -u netdata -s -
Run the
go.d.pluginto debug the collector:./go.d.plugin -d -m clickhouse
Getting Logs
If you’re encountering problems with the clickhouse collector, follow these steps to retrieve logs and identify potential issues:
- Run the command specific to your system (systemd, non-systemd, or Docker container).
- Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.
System with systemd
Use the following command to view logs generated since the last Netdata service restart:
journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep clickhouse
System without systemd
Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector’s name:
grep clickhouse /var/log/netdata/collector.log
Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.
Docker Container
If your Netdata runs in a Docker container named “netdata” (replace if different), use this command:
docker logs netdata 2>&1 | grep clickhouse