ClickHouse

Data Source

ClickHouse datasource for Grafana

ClickHouse datasource for Grafana 4.6+

ClickHouse datasource plugin provides a support for ClickHouse as a backend database.

Quick start

Install from grafana.net

OR

Copy files to your Grafana plugin directory. Restart Grafana, check datasources list at http://your.grafana.instance/datasources/new, choose ClickHouse option.

Features:

  • Access to CH via HTTP
  • Query setup
  • Raw SQL editor
  • Query formatting
  • Macros support
  • Additional functions
  • Templates
  • Table view
  • SingleStat view

Access to CH via HTTP

Page configuration is standard

settings

There is a small feature - ClickHouse treats HTTP Basic Authentication credentials as a database user and will try to run queries using its name.

CHProxy (optional)

Using of CHProxy will bring additional features:

  • Easily setup HTTPS access to ClickHouse as shown here to provide secure access.
  • Limit concurrency and time execution for requests from Grafana as shown here to prevent ClickHouse overloading from Grafana.
  • Protection against request bursts for dashboards with numerous graphs. CHProxy allows to queue requests and execute them sequentially. To learn more - read about params max_queue_size and max_queue_time at CHProxy page.
  • Response caching for the most frequent queries as shown here. Caching will protect ClickHouse from excessive refreshes and will be optimal option for popular dashboards.

Hint - if you need to cache requests like last 24h where timestamp changes constantly then try to use Round option at Raw Editor

Query setup

Query setup interface:

query editor image

First row FROM contains two options: database and table. Table values depends on selected database. Second row contains selectors for time filtering:

Plugin will try to detect date columns automatically

Column:DateTime or Column:TimeStamp are required for time-based macros and functions, because all analytics is based on these values

Button Go to Query is just a toggler to Raw SQL Editor

Raw SQL Editor

Raw Editor allows custom SQL queries to be written:

raw editor image

Raw Editor allows to type queries, get info about functions and macroses, format queries as Clickhouse do. Under the Editor you can find a raw query (all macros and functions have already been replaced) which will be sent directly to ClickHouse.

Macros

Plugin supports the following marcos:

  • $table - replaced with selected table name from Query Builder
  • $timeCol - replaced with Date:Col value from Query Builder
  • $dateTimeCol - replaced with Column:DateTime or Column:TimeStamp value from Query Builder
  • $from - replaced with timestamp/1000 value of selected "Time Range:From"
  • $to - replaced with timestamp/1000 value of selected "Time Range:To"
  • $interval - replaced with selected "Group by time interval" value (as a number of seconds)
  • $timeFilter - replaced with currently selected "Time Range". Require Column:Date and Column:DateTime or Column:TimeStamp to be selected
  • $timeSeries - replaced with special ClickHouse construction to convert results as time-series data. Use it as "SELECT $timeSeries...". Require Column:DateTime or Column:TimeStamp to be selected

A description of macros is available by typing their names in Raw Editor

Functions

Functions are just templates of SQL queries and you can check the final query at Raw SQL Editor mode. If some additional complexity is needed - just copy raw sql into Raw Editor and make according changes. Remember that macros are still available to use.

There are some limits in function use because of poor query analysis:

  • Column:Date and Column:DateTime or Column:TimeStamp must be set in Query Builder
  • Query must begins from function name
  • Only one function can be used per query

Plugin supports the following functions:

$rate(cols...) - converts query results as "change rate per interval"

Example usage:

$rate(countIf(Type = 200) AS good, countIf(Type != 200) AS bad) FROM requests

Query will be transformed into:

SELECT 
    t, 
    good / runningDifference(t / 1000) AS goodRate, 
    bad / runningDifference(t / 1000) AS badRate
FROM 
(
    SELECT 
        (intDiv(toUInt32(EventTime), 60)) * 1000 AS t, 
        countIf(Type = 200) AS good, 
        countIf(Type != 200) AS bad
    FROM requests 
    WHERE ((EventDate >= toDate(1482796747)) AND (EventDate <= toDate(1482853383))) AND ((EventTime >= toDateTime(1482796747)) AND (EventTime <= toDateTime(1482853383)))
    GROUP BY t
    ORDER BY t ASC
) 

$columns(key, value) - query values as array of [key, value], where key will be used as label

Example usage:

$columns(OSName, count(*) c) FROM requests

Query will be transformed into:

SELECT 
    t, 
    groupArray((OSName, c)) AS groupArr
FROM 
(
    SELECT 
        (intDiv(toUInt32(EventTime), 60) * 60) * 1000 AS t, 
        OSName, 
        count(*) AS c
    FROM requests 
    ANY INNER JOIN oses USING (OS)
    WHERE ((EventDate >= toDate(1482796627)) AND (EventDate <= toDate(1482853383))) AND ((EventTime >= toDateTime(1482796627)) AND (EventTime <= toDateTime(1482853383)))
    GROUP BY 
        t, 
        OSName
    ORDER BY 
        t ASC, 
        OSName ASC
) 
GROUP BY t
ORDER BY t ASC

This will help to build the next graph:

req_by_os image


$rateColumns(key, value) - is a combination of $columns and $rate

Example usage:

$rateColumns(OS, count(*) c) FROM requests

Query will be transformed into:

SELECT 
    t, 
    arrayMap(lambda(tuple(a), (a.1, a.2 / runningDifference(t / 1000))), groupArr)
FROM 
(
    SELECT 
        t, 
        groupArray((OS, c)) AS groupArr
    FROM 
    (
        SELECT 
            (intDiv(toUInt32(EventTime), 60) * 60) * 1000 AS t, 
            OS, 
            count(*) AS c
        FROM requests 
        WHERE ((EventDate >= toDate(1482796867)) AND (EventDate <= toDate(1482853383))) AND ((EventTime >= toDateTime(1482796867)) AND (EventTime <= toDateTime(1482853383)))
        GROUP BY 
            t, 
            OS
        ORDER BY 
            t ASC, 
            OS ASC
    ) 
    GROUP BY t
    ORDER BY t ASC
) 

Working with panels

Piechart (https://grafana.com/plugins/grafana-piechart-panel)

Remember that piechart plugin is not welcome for using in grafana - see https://grafana.com/blog/2015/12/04/friends-dont-let-friends-abuse-pie-charts

top5things

To create "Top 5" diagram we will need two queries: one for 'Top 5' rows and one for 'Other' row.

Top5:

SELECT
    1, /* fake timestamp value */
    groupArray((UserName,  Reqs))
FROM
(
    SELECT
        UserName,
        sum(Reqs) AS Reqs
    FROM requests
    GROUP BY UserName
    ORDER BY Reqs desc
    LIMIT 5
)

Other:

SELECT
    1, /* fake timestamp value */
    tuple(tuple('Other',  sum(Reqs)))
FROM
(
    SELECT
        UserName,
        sum(Reqs) AS Reqs
    FROM requests
    GROUP BY UserName
    ORDER BY Reqs desc
    LIMIT 5,10000000000000 /* select some ridiculous number after first 5 */
)

Table (https://grafana.com/plugins/table)

There are no any tricks in displaying time-series data. But to display some summary we will need to fake timestamp data:

SELECT
    rand() Time, /* fake timestamp value */
    UserName,
    sum(Reqs) as Reqs
FROM requests
GROUP BY
    UserName
ORDER BY 
    Reqs

Better to hide Time column at Options tab while editing panel

Vertical histogram (https://grafana.com/plugins/graph)

vertical histogram

To make vertical histogram from graph panel we will need to edit some settings:

  • Display -> Draw Modes -> Bars
  • Axes -> X-Axis -> Mode -> Series

And use next query:

$columns(
    Size,
    sum(Items) Items)
FROM some_table

// It is also possible to use query without macros

Contribute

Since we developed this plugin only for internal needs we don't have some of Grafana's features:

  • Alerts (this feature requires additional changes at backend and can't be solved by js-plugin)
  • Annotations
  • Labels

We know that code quality needs a tons of improvements and unit-tests. We will continue working on this. If you have any idea for an improvement or found a bug do not hesitate to open an issue or submit a pull request. We will appreciate any help from the community which will make working with such amazing products as ClickHouse and Grafana more convenient.

Plugin creation was inspired by great grafana-sqldb-datasource

License

MIT License, please see LICENSE for details.

Install Plugin

Version