Range Splitting: ignore empty queries from splitting and fix result resetting (#64053)

Range splitting: ignore empty queries from splitting

public/app/plugins/datasource/loki/queryUtils.test.ts

@@ -13,6 +13,7 @@ import {
   obfuscate,
   combineResponses,
   cloneQueryResponse,
+  requestSupportsPartitioning,
 } from './queryUtils';
 import { LokiQuery, LokiQueryType } from './types';
 
@@ -526,3 +527,47 @@ describe('combineResponses', () => {
     });
   });
 });
+
+describe('requestSupportsPartitioning', () => {
+  it('hidden requests are not partitioned', () => {
+    const requests: LokiQuery[] = [
+      {
+        expr: '{a="b"}',
+        refId: 'A',
+        hide: true,
+      },
+    ];
+    expect(requestSupportsPartitioning(requests)).toBe(false);
+  });
+  it('special requests are not partitioned', () => {
+    const requests: LokiQuery[] = [
+      {
+        expr: '{a="b"}',
+        refId: 'do-not-chunk',
+      },
+    ];
+    expect(requestSupportsPartitioning(requests)).toBe(false);
+  });
+  it('empty requests are not partitioned', () => {
+    const requests: LokiQuery[] = [
+      {
+        expr: '',
+        refId: 'A',
+      },
+    ];
+    expect(requestSupportsPartitioning(requests)).toBe(false);
+  });
+  it('all other requests are partitioned', () => {
+    const requests: LokiQuery[] = [
+      {
+        expr: '{a="b"}',
+        refId: 'A',
+      },
+      {
+        expr: 'count_over_time({a="b"}[1h])',
+        refId: 'B',
+      },
+    ];
+    expect(requestSupportsPartitioning(requests)).toBe(true);
+  });
+});

public/app/plugins/datasource/loki/queryUtils.ts

@@ -305,7 +305,10 @@ export function getStreamSelectorsFromQuery(query: string): string[] {
 }
 
 export function requestSupportsPartitioning(allQueries: LokiQuery[]) {
-  const queries = allQueries.filter((query) => !query.hide).filter((query) => !query.refId.includes('do-not-chunk'));
+  const queries = allQueries
+    .filter((query) => !query.hide)
+    .filter((query) => !query.refId.includes('do-not-chunk'))
+    .filter((query) => query.expr);
 
   const instantQueries = queries.some((query) => query.queryType === LokiQueryType.Instant);
   if (instantQueries) {