postgres: fix precision for the time column in table/annotation query mode

Use the ConvertSqlTimeColumnToEpochMs function to convert any native
datetime data type or epoch time (millisecond precision).
Additional tests and update of existing due to timezone issues
running postgres on UTC and dev environment on non-utc.
Added test dashboard.

pkg/tsdb/postgres/postgres.go

@@ -63,7 +63,6 @@ func (e *PostgresQueryEndpoint) Query(ctx context.Context, dsInfo *models.DataSo
 }
 
 func (e PostgresQueryEndpoint) transformToTable(query *tsdb.Query, rows *core.Rows, result *tsdb.QueryResult, tsdbQuery *tsdb.TsdbQuery) error {
-
 	columnNames, err := rows.Columns()
 	if err != nil {
 		return err
@@ -100,14 +99,10 @@ func (e PostgresQueryEndpoint) transformToTable(query *tsdb.Query, rows *core.Ro
 			return err
 		}
 
-		// convert column named time to unix timestamp to make
-		// native datetime postgres types work in annotation queries
-		if timeIndex != -1 {
-			switch value := values[timeIndex].(type) {
-			case time.Time:
-				values[timeIndex] = float64(value.UnixNano() / 1e9)
-			}
-		}
+		// converts column named time to unix timestamp in milliseconds to make
+		// native postgres datetime types and epoch dates work in
+		// annotation and table queries.
+		tsdb.ConvertSqlTimeColumnToEpochMs(values, timeIndex)
 
 		table.Rows = append(table.Rows, values)
 	}
@@ -118,7 +113,6 @@ func (e PostgresQueryEndpoint) transformToTable(query *tsdb.Query, rows *core.Ro
 }
 
 func (e PostgresQueryEndpoint) getTypedRowData(rows *core.Rows) (tsdb.RowValues, error) {
-
 	types, err := rows.ColumnTypes()
 	if err != nil {
 		return nil, err
@@ -209,7 +203,6 @@ func (e PostgresQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *co
 			fillValue.Float64 = query.Model.Get("fillValue").MustFloat64()
 			fillValue.Valid = true
 		}
-
 	}
 
 	for rows.Next() {

public/app/plugins/datasource/postgres/partials/annotations.editor.html

@@ -18,15 +18,16 @@
 
   <div class="gf-form"  ng-show="ctrl.showHelp">
 		<pre class="gf-form-pre alert alert-info"><h6>Annotation Query Format</h6>
-An annotation is an event that is overlayed on top of graphs. The query can have up to four columns per row, the time column is mandatory. Annotation rendering is expensive so it is important to limit the number of rows returned.
+An annotation is an event that is overlayed on top of graphs. The query can have up to three columns per row, the time column is mandatory. Annotation rendering is expensive so it is important to limit the number of rows returned.
 
-- column with alias: <b>time</b> for the annotation event. Format is UTC in seconds, use extract(epoch from column) as "time"
+- column with alias: <b>time</b> for the annotation event time. Use epoch time or any native date data type.
 - column with alias: <b>text</b> for the annotation text
 - column with alias: <b>tags</b> for annotation tags. This is a comma separated string of tags e.g. 'tag1,tag2'
 
 
 Macros:
 - $__time(column) -&gt; column as "time"
+- $__timeEpoch -&gt; extract(epoch from column) as "time"
 - $__timeFilter(column) -&gt;  column &ge; to_timestamp(1492750877) AND column &le; to_timestamp(1492750877)
 - $__unixEpochFilter(column) -&gt;  column &gt; 1492750877 AND column &lt; 1492750877
 

public/app/plugins/datasource/postgres/response_parser.ts

@@ -134,7 +134,7 @@ export default class ResponseParser {
       const row = table.rows[i];
       list.push({
         annotation: options.annotation,
-        time: Math.floor(row[timeColumnIndex]) * 1000,
+        time: Math.floor(row[timeColumnIndex]),
         title: row[titleColumnIndex],
         text: row[textColumnIndex],
         tags: row[tagsColumnIndex] ? row[tagsColumnIndex].trim().split(/\s*,\s*/) : [],