Using PostgreSQL in Grafana
NOTE: In 9.5.18, 9.4.23, 9.6.14, 10.9, 11.4, 12-beta2 versions of PostgreSQL has a bug which prevents execution of multiple column modifications via
ALTER TABLEstatement. Because Grafana uses it during initial database set up and since PostgreSQL has fixed this issue, Grafana does not support these versions
Grafana ships with a built-in PostgreSQL data source plugin that allows you to query and visualize data from a PostgreSQL compatible database.
Adding the data source
- Open the side menu by clicking the Grafana icon in the top header.
- In the side menu under the
Configurationicon you should find a link named
- Click the
+ Add data sourcebutton in the top header.
- Select PostgreSQL from the Type dropdown.
Data source options
|Name||The data source name. This is how you refer to the data source in panels & queries.|
|Default||Default data source means that it will be pre-selected for new panels.|
|Host||The IP address/hostname and optional port of your PostgreSQL instance.|
|Database||Name of your PostgreSQL database.|
|User||Database user’s login/username|
|Password||Database user’s password|
|SSL Mode||This option determines whether or with what priority a secure SSL TCP/IP connection will be negotiated with the server.|
|Max open||The maximum number of open connections to the database, default |
|Max idle||The maximum number of connections in the idle connection pool, default |
|Max lifetime||The maximum amount of time in seconds a connection may be reused, default |
|Version||This option determines which functions are available in the query builder (only available in Grafana 5.3+).|
|TimescaleDB||TimescaleDB is a time-series database built as a PostgreSQL extension. If enabled, Grafana will use |
Min time interval
A lower limit for the $__interval and $__interval_ms variables. Recommended to be set to write frequency, for example
1m if your data is written every minute. This option can also be overridden/configured in a dashboard panel under data source options. It’s important to note that this value needs to be formatted as a number followed by a valid time identifier, e.g.
1m (1 minute) or
30s (30 seconds). The following time identifiers are supported:
Database User Permissions (Important!)
The database user you specify when you add the data source should only be granted SELECT permissions on the specified database & tables you want to query. Grafana does not validate that the query is safe. The query could include any SQL statement. For example, statements like
DELETE FROM user; and
DROP TABLE user; would be executed. To protect against this we highly recommend you create a specific PostgreSQL user with restricted permissions.
CREATE USER grafanareader WITH PASSWORD 'password'; GRANT USAGE ON SCHEMA schema TO grafanareader; GRANT SELECT ON schema.table TO grafanareader;
Make sure the user does not get any unwanted privileges from the public role.
Only available in Grafana v5.3+.
You find the PostgreSQL query editor in the metrics tab in Graph or Singlestat panel’s edit mode. You enter edit mode by clicking the panel title, then edit.
The query editor has a link named
Generated SQL that shows up after a query has been executed, while in panel edit mode. Click on it and it will expand and show the raw interpolated SQL string that was executed.
Select table, time column and metric column (FROM)
When you enter edit mode for the first time or add a new query Grafana will try to prefill the query builder with the first table that has a timestamp column and a numeric column.
In the FROM field, Grafana will suggest tables that are in the
search_path of the database user. To select a table or view not in your
search_path you can manually enter a fully qualified name (schema.table) like
The Time column field refers to the name of the column holding your time values. Selecting a value for the Metric column field is optional. If a value is selected, the Metric column field will be used as the series name.
The metric column suggestions will only contain columns with a text datatype (char,varchar,text). If you want to use a column with a different datatype as metric column you may enter the column name with a cast:
ip::text. You may also enter arbitrary SQL expressions in the metric column field that evaluate to a text datatype like
hostname || ' ' || container_name.
Columns, Window and Aggregation functions (SELECT)
SELECT row you can specify what columns and functions you want to use. In the column field you may write arbitrary expressions instead of a column name like
column1 * column2 / column3.
The available functions in the query editor depend on the PostgreSQL version you selected when configuring the datasource. If you use aggregate functions you need to group your resultset. The editor will automatically add a
GROUP BY time if you add an aggregate function.
The editor tries to simplify and unify this part of the query. For example:
The above will generate the following PostgreSQL
avg(tx_bytes) OVER (ORDER BY "time" ROWS 5 PRECEDING) AS "tx_bytes"
You may add further value columns by clicking the plus button and selecting
Column from the menu. Multiple value columns will be plotted as separate series in the graph panel.
Filter data (WHERE)
To add a filter click the plus icon to the right of the
WHERE condition. You can remove filters by clicking on the filter and selecting
Remove. A filter for the current selected timerange is automatically added to new queries.
To group by time or any other columns click the plus icon at the end of the GROUP BY row. The suggestion dropdown will only show text columns of your currently selected table but you may manually enter any column. You can remove the group by clicking on the item and then selecting
If you add any grouping, all selected columns need to have an aggregate function applied. The query builder will automatically add aggregate functions to all columns without aggregate functions when you add groupings.
Grafana can fill in missing values when you group by time. The time function accepts two arguments. The first argument is the time window that you would like to group by, and the second argument is the value you want Grafana to fill missing items with.
Text Editor Mode (RAW)
You can switch to the raw query editor mode by clicking the hamburger icon and selecting
Switch editor mode or by clicking
Edit SQL below the query.
If you use the raw query editor, be sure your query at minimum has
ORDER BY timeand a filter on the returned time range.
Macros can be used within a query to simplify syntax and allow for dynamic parts.
|$__time(dateColumn)||Will be replaced by an expression to rename the column to |
|$__timeSec(dateColumn)||Will be replaced by an expression to rename the column to |
|$__timeFilter(dateColumn)||Will be replaced by a time range filter using the specified column name. For example, dateColumn BETWEEN ‘2017-04-21T05:01:17Z’ AND ‘2017-04-21T05:06:17Z’|
|$__timeFrom()||Will be replaced by the start of the currently active time selection. For example, ‘2017-04-21T05:01:17Z’|
|$__timeTo()||Will be replaced by the end of the currently active time selection. For example, ‘2017-04-21T05:06:17Z’|
|$__timeGroup(dateColumn,‘5m’)||Will be replaced by an expression usable in a GROUP BY clause. For example, *(extract(epoch from dateColumn)/300)::bigint300|
|$__timeGroup(dateColumn,‘5m’, 0)||Same as above but with a fill parameter so missing points in that series will be added by Grafana and 0 will be used as the value.|
|$__timeGroup(dateColumn,‘5m’, NULL)||Same as above but NULL will be used as value for missing points.|
|$__timeGroup(dateColumn,‘5m’, previous)||Same as above but the previous value in that series will be used as fill value. If no value has been seen yet, NULL will be used (only available in Grafana 5.3+).|
|$__timeGroupAlias(dateColumn,‘5m’)||Will be replaced with an expression identical to $__timeGroup, but with an added column alias (only available in Grafana 5.3+).|
|$__unixEpochFilter(dateColumn)||Will be replaced by a time range filter using the specified column name with times represented as unix timestamps. For example, dateColumn >= 1494410783 AND dateColumn <= 1494497183|
|$__unixEpochFrom()||Will be replaced by the start of the currently active time selection as unix timestamp. For example, 1494410783|
|$__unixEpochTo()||Will be replaced by the end of the currently active time selection as unix timestamp. For example, 1494497183|
|$__unixEpochNanoFilter(dateColumn)||Will be replaced by a time range filter using the specified column name with times represented as nanosecond timestamps. For example, dateColumn >= 1494410783152415214 AND dateColumn <= 1494497183142514872|
|$__unixEpochNanoFrom()||Will be replaced by the start of the currently active time selection as nanosecond timestamp. For example, 1494410783152415214|
|$__unixEpochNanoTo()||Will be replaced by the end of the currently active time selection as unix timestamp. For example, 1494497183142514872|
|$__unixEpochGroup(dateColumn,‘5m’, [fillmode])||Same as $__timeGroup, but for times stored as unix timestamp (only available in Grafana 5.3+).|
|$__unixEpochGroupAlias(dateColumn,‘5m’, [fillmode])||Same as above, but also adds a column alias (only available in Grafana 5.3+).|
We plan to add many more macros. If you have suggestions for what macros you would like to see, please open an issue in our GitHub repo.
Format as query option is set to
Table then you can basically do any type of SQL query. The table panel will automatically show the results of whatever columns & rows your query returns.
Query editor with example query:
SELECT title as "Title", "user".login as "Created By", dashboard.created as "Created On" FROM dashboard INNER JOIN "user" on "user".id = dashboard.created_by WHERE $__timeFilter(dashboard.created)
You can control the name of the Table panel columns by using regular
as SQL column selection syntax.
The resulting table panel:
Time series queries
If you set
Format as to
Time series, for use in Graph panel for example, then the query must return a column named
time that returns either a SQL datetime or any numeric datatype representing unix epoch. Any column except
metric are treated as a value column. You may return a column named
metric that is used as metric name for the value column. If you return multiple value columns and a column named
metric then this column is used as prefix for the series name (only available in Grafana 5.3+).
Resultsets of time series queries need to be sorted by time.
SELECT $__timeGroup("time_date_time",'5m'), min("value_double"), 'min' as metric FROM test_data WHERE $__timeFilter("time_date_time") GROUP BY time ORDER BY time
Example using the fill parameter in the $__timeGroup macro to convert null values to be zero instead:
SELECT $__timeGroup("createdAt",'5m',0), sum(value) as value, measurement FROM test_data WHERE $__timeFilter("createdAt") GROUP BY time, measurement ORDER BY time
Example with multiple columns:
SELECT $__timeGroup("time_date_time",'5m'), min("value_double") as "min_value", max("value_double") as "max_value" FROM test_data WHERE $__timeFilter("time_date_time") GROUP BY time ORDER BY time
Instead of hard-coding things like server, application and sensor name in you metric queries you can use variables in their place. Variables are shown as dropdown select boxes at the top of the dashboard. These dropdowns makes it easy to change the data being displayed in your dashboard.
Checkout the Templating documentation for an introduction to the templating feature and the different types of template variables.
If you add a template variable of the type
Query, you can write a PostgreSQL query that can return things like measurement names, key names or key values that are shown as a dropdown select box.
For example, you can have a variable that contains all values for the
hostname column in a table if you specify a query like this in the templating variable Query setting.
SELECT hostname FROM host
A query can return multiple columns and Grafana will automatically create a list from them. For example, the query below will return a list with values from
SELECT host.hostname, other_host.hostname2 FROM host JOIN other_host ON host.city = other_host.city
To use time range dependent macros like
$__timeFilter(column) in your query the refresh mode of the template variable needs to be set to On Time Range Change.
SELECT event_name FROM event_log WHERE $__timeFilter(time_column)
Another option is a query that can create a key/value variable. The query should return two columns that are named
__text column value should be unique (if it is not unique then the first value is used). The options in the dropdown will have a text and value that allows you to have a friendly name as text and an id as the value. An example query with
hostname as the text and
id as the value:
SELECT hostname AS __text, id AS __value FROM host
You can also create nested variables. Using a variable named
region, you could have the hosts variable only show hosts from the current selected region with a query like this (if
region is a multi-value variable then use the
IN comparison operator rather than
= to match against multiple values):
SELECT hostname FROM host WHERE region IN($region)
Using Variables in Queries
From Grafana 4.3.0 to 4.6.0, template variables are always quoted automatically. If your template variables are strings, do not wrap them in quotes in where clauses.
From Grafana 4.7.0, template variable values are only quoted when the template variable is a
If the variable is a multi-value variable then use the
IN comparison operator rather than
= to match against multiple values.
There are two syntaxes:
$<varname> Example with a template variable named
SELECT atimestamp as time, aint as value FROM table WHERE $__timeFilter(atimestamp) and hostname in($hostname) ORDER BY atimestamp ASC
[[varname]] Example with a template variable named
SELECT atimestamp as time, aint as value FROM table WHERE $__timeFilter(atimestamp) and hostname in([[hostname]]) ORDER BY atimestamp ASC
Disabling Quoting for Multi-value Variables
Grafana automatically creates a quoted, comma-separated string for multi-value variables. For example: if
server02 are selected then it will be formatted as:
'server01', 'server02'. To disable quoting, use the csv formatting option for variables:
Read more about variable formatting options in the Variables documentation.
Annotations allow you to overlay rich event information on top of graphs. You add annotation queries via the Dashboard menu / Annotations view.
Example query using time column with epoch values:
SELECT epoch_time as time, metric1 as text, concat_ws(', ', metric1::text, metric2::text) as tags FROM public.test_data WHERE $__unixEpochFilter(epoch_time)
Example query using time column of native sql date/time data type:
SELECT native_date_time as time, metric1 as text, concat_ws(', ', metric1::text, metric2::text) as tags FROM public.test_data WHERE $__timeFilter(native_date_time)
|time||The name of the date/time field. Could be a column with a native sql date/time data type or epoch value.|
|text||Event description field.|
|tags||Optional field name to use for event tags as a comma separated string.|
Time series queries should work in alerting conditions. Table formatted queries are not yet supported in alert rule conditions.
Configure the Datasource with Provisioning
It’s now possible to configure datasources using config files with Grafana’s provisioning system. You can read more about how it works and all the settings you can set for datasources on the provisioning docs page
Here are some provisioning examples for this datasource.
apiVersion: 1 datasources: - name: Postgres type: postgres url: localhost:5432 database: grafana user: grafana secureJsonData: password: "Password!" jsonData: sslmode: "disable" # disable/require/verify-ca/verify-full maxOpenConns: 0 # Grafana v5.4+ maxIdleConns: 2 # Grafana v5.4+ connMaxLifetime: 14400 # Grafana v5.4+ postgresVersion: 903 # 903=9.3, 904=9.4, 905=9.5, 906=9.6, 1000=10 timescaledb: false