> 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.
| _URL_ | The URL of the Loki instance, e.g., `http://localhost:3100` |
| _Maximum lines_ | Upper limit for number of log lines returned by Loki (default is 1000). Decrease if your browser is sluggish when displaying logs in Explore. |
Querying and displaying log data from Loki is available via [Explore](/features/explore), and with the [logs panel](/features/panels/logs/) in dashboards. Select the Loki data source, and then enter a log query to display your logs.
A log query consists of two parts: **log stream selector**, and a **search expression**. For performance reasons you need to start by choosing a log stream by selecting a log label.
The Logs Explorer (the `Log labels` button) next to the query field shows a list of labels of available log streams. An alternative way to write a query is to use the query field's autocomplete - you start by typing a left curly brace `{` and the autocomplete menu will suggest a list of labels. Press the `enter` key to execute the query.
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.
For the label part of the query expression, wrap it in curly braces `{}` and then use the key value syntax for selecting labels. Multiple label expressions are separated by a comma:
`{app="mysql",name="mysql-backup"}`
The following label matching operators are currently supported:
*`=` exactly equal.
*`!=` not equal.
*`=~` regex-match.
*`!~` do not regex-match.
Examples:
*`{name=~"mysql.+"}`
*`{name!~"mysql.+"}`
The [same rules that apply for Prometheus Label Selectors](https://prometheus.io/docs/prometheus/latest/querying/basics/#instant-vector-selectors) apply for Loki Log Stream Selectors.
Another way to add a label selector, is in the table section, clicking on the **Filter** button beside a label will add the label to the query expression. This even works for multiple queries and will the label selector to each query.
### Search Expression
After writing the Log Stream Selector, you can filter the results further by writing a search expression. The search expression can be just text or a regex expression.
> Note: For more details about LogQL, Loki's query language, refer to the [documentation](https://github.com/grafana/loki/blob/master/docs/querying.md)
## Live tailing
Loki supports Live tailing which displays logs in real-time. This feature is supported in [Explore](/features/explore/#loki-specific-features) and in dashboards with a Live toggle in the query editor.
Note that Live Tailing relies on two Websocket connections: one between the browser and the Grafana server, and another between the Grafana server and the Loki server. If you run any reverse proxies, please configure them accordingly.
> Note: This feature is only available in Grafana v6.3+
## Log Context
When using a search expression as detailed above, you now have the ability to retrieve the context surrounding your filtered results.
By clicking the `Show Context` link on the filtered rows, you'll be able to investigate the log messages that came before and after the
log message you're interested in.
> Note: This feature is only available in Grafana v6.3+
Instead of hard-coding things like server, application and sensor name in your metric queries, you can use variables in their place. Variables are shown as drop-down select boxes at the top of the dashboard. These drop-down boxes make it easy to change the data being displayed in your dashboard.
Checkout the [Templating](/reference/templating) documentation for an introduction to the templating feature and the different types of template variables.
You can use any non-metric Loki query as a source for annotations. Log content will be used as annotation text, so there is no need for additional mapping.
> Note: Annotations for Loki are only available in Grafana v6.4+
You can set up the data source via 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)
