MySQL Datasource: Add timezone parameter (#27535)

* Add MySQL timezone parameter

* Reword docs/sources/features/datasources/mysql.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

* update documentation

* fix formatting mistake from merge

* enhance documentation with reason for parameter usage

* enhance documentation with reason for parameter usage

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

docs/sources/datasources/mysql.md

@@ -22,13 +22,14 @@ Grafana ships with a built-in MySQL data source plugin that allows you to query
 ### Data source options
 
 Name               | Description
--------------- | -------------
+------------------ | -------------
 `Name`             | The data source name. This is how you refer to the data source in panels and 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 MySQL instance.
 `Database`         | Name of your MySQL database.
 `User`             | Database user's login/username
 `Password`         | Database user's password
+`Session Timezone` | Specify the time zone used in the database session, such as `Europe/Berlin` or `+02:00`. This is necessary, if the timezone of the database (or the host of the database) is set to something other than UTC. Set the value used in the session with `SET time_zone='...'`. If you leave this field empty, then the time zone is not updated. For more information, refer to the [MySQL documentation](https://dev.mysql.com/doc/refman/8.0/en/time-zone-support.html).
 `Max open`         | The maximum number of open connections to the database, default `unlimited` (Grafana v5.4+).
 `Max idle`         | The maximum number of connections in the idle connection pool, default `2` (Grafana v5.4+).
 `Max lifetime`     | The maximum amount of time in seconds a connection may be reused, default `14400`/4 hours. This should always be lower than configured [wait_timeout](https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_wait_timeout) in MySQL (Grafana v5.4+).

pkg/tsdb/mysql/mysql.go

@@ -64,6 +64,13 @@ func New(httpClientProvider httpclient.Provider) func(datasource *models.DataSou
 			cnnstr += "&tls=" + tlsConfigString
 		}
 
+		if datasource.JsonData != nil {
+			timezone, hasTimezone := datasource.JsonData.CheckGet("timezone")
+			if hasTimezone && timezone.MustString() != "" {
+				cnnstr += fmt.Sprintf("&time_zone='%s'", url.QueryEscape(timezone.MustString()))
+			}
+		}
+
 		if setting.Env == setting.Dev {
 			logger.Debug("getEngine", "connection", cnnstr)
 		}

public/app/plugins/datasource/mysql/partials/config.html

@@ -27,6 +27,24 @@
 		</div>
 	</div>
 
+  <div class="gf-form max-width-30">
+    <span class="gf-form-label width-10">Session Timezone</span>
+    <input
+            type="text"
+            class="gf-form-input gf-form-input--has-help-icon"
+            ng-model="ctrl.current.jsonData.timezone"
+            spellcheck='false'
+            placeholder="(default)"
+    ></input>
+    <info-popover mode="right-absolute">
+      Specify the time zone used in the database session, e.g. <code>Europe/Berlin</code> or <code>+02:00</code>.
+      This is necessary, if the timezone of the database (or the host of the database) is set to something other than UTC.
+      The value is set in the session with <code>SET time_zone='...'</code>. If you leave this field empty,
+      the timezone is not updated. You can find more information in the
+      <a href="https://dev.mysql.com/doc/refman/8.0/en/time-zone-support.html">MySQL documentation</a>.
+    </info-popover>
+  </div>
+
 	<div class="gf-form-group">
 		<div class="gf-form-inline">
 			<gf-form-checkbox class="gf-form" label="TLS Client Auth" label-class="width-10"