Explore: Fixes query hint issues (#18803)

* Explore: clear results when you change datasource

* Explore: Clear results on data source change, and fix query hints issue

* Clear results on clear all

* Prometheus: Update logic of when to re-check query hints

packages/grafana-data/src/utils/processDataFrame.ts

@@ -96,10 +96,11 @@ function convertTimeSeriesToDataFrame(timeSeries: TimeSeries): DataFrame {
 function convertGraphSeriesToDataFrame(graphSeries: GraphSeriesXY): DataFrame {
   const x = new ArrayVector();
   const y = new ArrayVector();
+
   for (let i = 0; i < graphSeries.data.length; i++) {
     const row = graphSeries.data[i];
-    x.buffer.push(row[0]);
-    y.buffer.push(row[1]);
+    x.buffer.push(row[1]);
+    y.buffer.push(row[0]);
   }
 
   return {

public/app/features/explore/state/reducers.test.ts

@@ -157,6 +157,9 @@ describe('Explore item reducer', () => {
             showingStartPage: true,
             queries,
             queryKeys,
+            graphResult: null,
+            logsResult: null,
+            tableResult: null,
             supportedModes: [ExploreMode.Metrics, ExploreMode.Logs],
             mode: ExploreMode.Metrics,
             loadingState: LoadingState.NotStarted,

public/app/features/explore/state/reducers.ts

@@ -210,6 +210,9 @@ export const itemReducer = reducerFactory<ExploreItemState>({} as ExploreItemSta
       return {
         ...state,
         queries: queries.slice(),
+        graphResult: null,
+        tableResult: null,
+        logsResult: null,
         showingStartPage: Boolean(state.StartPage),
         queryKeys: getQueryKeys(queries, state.datasourceInstance),
       };
@@ -271,6 +274,9 @@ export const itemReducer = reducerFactory<ExploreItemState>({} as ExploreItemSta
         ...state,
         datasourceInstance,
         queryErrors: [],
+        graphResult: null,
+        tableResult: null,
+        logsResult: null,
         latency: 0,
         loadingState: LoadingState.NotStarted,
         StartPage,

public/app/plugins/datasource/prometheus/components/PromQueryField.tsx

@@ -109,7 +109,7 @@ interface PromQueryFieldProps extends ExploreQueryFieldProps<PrometheusDatasourc
 interface PromQueryFieldState {
   metricsOptions: any[];
   syntaxLoaded: boolean;
-  hint: QueryHint;
+  hint: QueryHint | null;
 }
 
 class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryFieldState> {
@@ -154,8 +154,7 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
 
   componentDidUpdate(prevProps: PromQueryFieldProps) {
     const { queryResponse } = this.props;
-    const currentHasSeries = queryResponse && queryResponse.series && queryResponse.series.length > 0 ? true : false;
-    if (currentHasSeries && prevProps.queryResponse && prevProps.queryResponse.series !== queryResponse.series) {
+    if (prevProps.queryResponse && prevProps.queryResponse.series !== queryResponse.series) {
       this.refreshHint();
     }
 
@@ -177,7 +176,9 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
 
   refreshHint = () => {
     const { datasource, query, queryResponse } = this.props;
-    if (!queryResponse || !queryResponse.series || queryResponse.series.length === 0) {
+
+    if (!queryResponse.series || queryResponse.series.length === 0) {
+      this.setState({ hint: null });
       return;
     }