> NOTE: If you're not seeing the `Data Sources` link in your side menu it means that your current user does not have the `Admin` role for the current organization.
*HTTP mode* | How to query the database (`GET` or `POST` HTTP verb). The `POST` verb allows heavy queries that would return an error using the `GET` verb. Default is `GET`.
All requests will be made from the browser to Grafana backend/server which in turn will forward the requests to the data source and by that circumvent possible Cross-Origin Resource Sharing (CORS) requirements. The URL needs to be accessible from the grafana backend/server if you select this access mode.
### Browser access mode
All requests will be made from the browser directly to the data source and may be subject to Cross-Origin Resource Sharing (CORS) requirements. The URL needs to be accessible from the browser if you select this access mode.
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
group by time you need an aggregation function. Some functions like derivative require an aggregation function. The editor tries simplify and unify this part of the query. For example:<br>
- $tag_exampletag = replaced with the value of the `exampletag` tag. The syntax is `$tag_yourTagName` (must start with `$tag_`). To use your tag as an alias in the ALIAS BY field then the tag must be used to group by in the query.
- You can also use [[tag_hostname]] pattern replacement syntax. For example, in the ALIAS BY field using this text `Host: [[tag_hostname]]` would substitute in the `hostname` tag value for each legend value and an example legend value would be: `Host: server1`.
Querying and displaying log data from InfluxDB is available via [Explore](/features/explore).
Select the InfluxDB data source, change to Logs using the Metrics/Logs switcher,
and then use the `Measurements/Fields` button to display your logs.
### Log Queries
The Logs Explorer (the `Measurements/Fields` button) next to the query field shows a list of measurements and fields. Choose the desired measurement that contains your log data and then choose which field Explore should use to display the log message.
Once the result is returned, the log panel shows a list of log rows and a bar chart where the x-axis shows the time and the y-axis shows the frequency/count.
### Filter search
To add a filter click the plus icon to the right of the `Measurements/Fields` button or a condition. You can remove tag filters by clicking on the first select and choosing `--remove filter--`.
Checkout the [Templating]({{< relref "../../reference/templating.md" >}}) documentation for an introduction to the templating feature and the different
If you add a template variable of the type `Query` you can write a InfluxDB exploration (meta data) query. These queries can
return things like measurement names, key names or key values.
For example you can have a variable that contains all values for tag `hostname` if you specify a query like this in the templating variable *Query* setting.
If you have a variable with key names you can use this variable in a group by clause. This will allow you to change group by using the variable dropdown at the top
SELECT mean("value") FROM "logins" WHERE "hostname" =~ /^$host$/ AND $timeFilter GROUP BY time($__interval), "hostname"
```
`[[varname]]` Example:
```sql
SELECT mean("value") FROM "logins" WHERE "hostname" =~ /^[[host]]$/ AND $timeFilter GROUP BY time($__interval), "hostname"
```
Why two ways? The first syntax is easier to read and write but does not allow you to use a variable in the middle of a word. When the *Multi-value* or *Include all value*
options are enabled, Grafana converts the labels from plain text to a regex compatible string. Which means you have to use `=~` instead of `=`.
InfluxDB supports the special `Ad hoc filters` variable type. This variable allows you to specify any number of key/value filters on the fly. These filters will automatically
It's now possible to configure data sources using config files with Grafana's provisioning system. You can read more about how it works and all the settings you can set for data sources on the [provisioning docs page](/administration/provisioning/#datasources)
