FieldValues: Use plain arrays instead of Vector (part 1 of 2) (#66187)

Co-authored-by: Leon Sorokin <leeoniya@gmail.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

public/app/features/transformers/lookupGazetteer/fieldLookup.ts

@@ -1,7 +1,6 @@
 import { mergeMap, from } from 'rxjs';
 
 import {
-  ArrayVector,
   DataFrame,
   DataTransformerID,
   Field,
@@ -53,12 +52,12 @@ export function addFieldsFromGazetteer(frames: DataFrame[], gaz: Gazetteer, matc
 
       //if the field matches
       if (matcher(field, frame, frames)) {
-        const values = field.values.toArray();
+        const values = field.values;
         const sub: any[][] = [];
         for (const f of src) {
           const buffer = new Array(length);
           sub.push(buffer);
-          fields.push({ ...f, values: new ArrayVector(buffer) });
+          fields.push({ ...f, values: buffer });
         }
 
         // Add all values to the buffer

public/app/features/transformers/timeSeriesTable/timeSeriesTableTransformer.test.ts

@@ -15,8 +15,8 @@ describe('timeSeriesTableTransformer', () => {
     const result = results[0];
     expect(result.refId).toBe('A');
     expect(result.fields).toHaveLength(3);
-    expect(result.fields[0].values.toArray()).toEqual(['A', 'A', 'A']);
-    expect(result.fields[1].values.toArray()).toEqual(['B', 'C', 'D']);
+    expect(result.fields[0].values).toEqual(['A', 'A', 'A']);
+    expect(result.fields[1].values).toEqual(['B', 'C', 'D']);
     assertDataFrameField(result.fields[2], series);
   });
 
@@ -33,8 +33,8 @@ describe('timeSeriesTableTransformer', () => {
     expect(results[0]).toEqual(series[0]);
     expect(results[1].refId).toBe('A');
     expect(results[1].fields).toHaveLength(3);
-    expect(results[1].fields[0].values.toArray()).toEqual(['A', 'A']);
-    expect(results[1].fields[1].values.toArray()).toEqual(['B', 'C']);
+    expect(results[1].fields[0].values).toEqual(['A', 'A']);
+    expect(results[1].fields[1].values).toEqual(['B', 'C']);
     expect(results[2]).toEqual(series[3]);
   });
 
@@ -51,14 +51,14 @@ describe('timeSeriesTableTransformer', () => {
     expect(results).toHaveLength(2);
     expect(results[0].refId).toBe('A');
     expect(results[0].fields).toHaveLength(3);
-    expect(results[0].fields[0].values.toArray()).toEqual(['A', 'A', 'A']);
-    expect(results[0].fields[1].values.toArray()).toEqual(['B', 'C', 'D']);
+    expect(results[0].fields[0].values).toEqual(['A', 'A', 'A']);
+    expect(results[0].fields[1].values).toEqual(['B', 'C', 'D']);
     assertDataFrameField(results[0].fields[2], series.slice(0, 3));
     expect(results[1].refId).toBe('B');
     expect(results[1].fields).toHaveLength(4);
-    expect(results[1].fields[0].values.toArray()).toEqual(['B', 'B']);
-    expect(results[1].fields[1].values.toArray()).toEqual(['F', 'G']);
-    expect(results[1].fields[2].values.toArray()).toEqual(['A', 'B']);
+    expect(results[1].fields[0].values).toEqual(['B', 'B']);
+    expect(results[1].fields[1].values).toEqual(['F', 'G']);
+    expect(results[1].fields[2].values).toEqual(['A', 'B']);
     assertDataFrameField(results[1].fields[3], series.slice(3, 5));
   });
 });
@@ -66,12 +66,12 @@ describe('timeSeriesTableTransformer', () => {
 function assertFieldsEqual(field1: Field, field2: Field) {
   expect(field1.type).toEqual(field2.type);
   expect(field1.name).toEqual(field2.name);
-  expect(field1.values.toArray()).toEqual(field2.values.toArray());
+  expect(field1.values).toEqual(field2.values);
   expect(field1.labels ?? {}).toEqual(field2.labels ?? {});
 }
 
 function assertDataFrameField(field: Field, matchesFrames: DataFrame[]) {
-  const frames: DataFrame[] = field.values.toArray();
+  const frames: DataFrame[] = field.values;
   expect(frames).toHaveLength(matchesFrames.length);
   frames.forEach((frame, idx) => {
     const matchingFrame = matchesFrames[idx];

public/app/features/transformers/timeSeriesTable/timeSeriesTableTransformer.ts

@@ -68,7 +68,11 @@ export function timeSeriesToTableTransform(options: TimeSeriesTableTransformerOp
         values: new ArrayVector(),
       };
       refId2frameField[refId] = frameField;
-      const table = new MutableDataFrame();
+
+      // NOTE: MutableDataFrame.addField() makes copies, including any .values buffers
+      // since we do .values.add() later on the *originals*, we pass a custom MutableVectorCreator
+      // which will re-use the existing empty .values buffer by reference
+      const table = new MutableDataFrame(undefined, (buffer) => buffer ?? []);
       for (const label of Object.values(labelFields)) {
         table.addField(label);
       }
@@ -81,7 +85,7 @@ export function timeSeriesToTableTransform(options: TimeSeriesTableTransformerOp
     const labels = frame.fields[1].labels;
     for (const labelKey of Object.keys(labelFields)) {
       const labelValue = labels?.[labelKey] ?? null;
-      labelFields[labelKey].values.add(labelValue);
+      labelFields[labelKey].values.add(labelValue!);
     }
 
     frameField.values.add(frame);