pass interval through

src/plugins/data/common/search/aggs/buckets/histogram.test.ts

@@ -12,6 +12,8 @@ import { AggTypesDependencies } from '../agg_types';
 import { BUCKET_TYPES } from './bucket_agg_types';
 import { IBucketHistogramAggConfig, getHistogramBucketAgg, AutoBounds } from './histogram';
 import { BucketAggType } from './bucket_agg_type';
+import { SerializableState } from 'src/plugins/expressions/common';
+import { isSerializedAutoInterval } from '../utils/get_number_histogram_interval';
 
 describe('Histogram Agg', () => {
   let aggTypesDependencies: AggTypesDependencies;
@@ -230,6 +232,27 @@ describe('Histogram Agg', () => {
         expect(params.interval).toBeNaN();
       });
 
+      test('will serialize the auto interval along with the actually chosen interval and deserialize correctly', () => {
+        const aggConfigs = getAggConfigs({
+          interval: 'auto',
+          field: {
+            name: 'field',
+          },
+        });
+        (aggConfigs.aggs[0] as IBucketHistogramAggConfig).setAutoBounds({ min: 0, max: 1000 });
+        const serializedAgg = aggConfigs.aggs[0].serialize();
+        const serializedIntervalParam = (serializedAgg.params as SerializableState).interval;
+        expect(isSerializedAutoInterval(serializedIntervalParam as string | number)).toBe(true);
+        const freshHistogramAggConfig = getAggConfigs({
+          interval: 100,
+          field: {
+            name: 'field',
+          },
+        }).aggs[0];
+        freshHistogramAggConfig.setParams(serializedAgg.params);
+        expect(freshHistogramAggConfig.getParam('interval')).toEqual('auto');
+      });
+
       describe('interval scaling', () => {
         const getInterval = (
           maxBars: number,

src/plugins/data/common/search/aggs/buckets/histogram.ts

@@ -20,6 +20,10 @@ import { aggHistogramFnName } from './histogram_fn';
 import { ExtendedBounds } from './lib/extended_bounds';
 import { isAutoInterval, autoInterval } from './_interval_options';
 import { calculateHistogramInterval } from './lib/histogram_calculate_interval';
+import {
+  buildSerializedAutoInterval,
+  isSerializedAutoInterval,
+} from '../utils/get_number_histogram_interval';
 
 export interface AutoBounds {
   min: number;
@@ -152,6 +156,29 @@ export const getHistogramBucketAgg = ({
             esTypes: aggConfig.params.field?.spec?.esTypes || [],
           });
         },
+        serialize(val, aggConfig) {
+          // store actually used auto interval in serialized agg config to be able to read it from the result data table meta information
+          const autoBounds = aggConfig?.getAutoBounds();
+          if (aggConfig && autoBounds) {
+            const usedInterval = calculateHistogramInterval({
+              values: autoBounds,
+              interval: aggConfig.params.interval,
+              maxBucketsUiSettings: getConfig(UI_SETTINGS.HISTOGRAM_MAX_BARS),
+              maxBucketsUserInput: aggConfig.params.maxBars,
+              intervalBase: aggConfig.params.intervalBase,
+              esTypes: aggConfig.params.field?.spec?.esTypes || [],
+            });
+            return buildSerializedAutoInterval(usedInterval);
+          } else {
+            return val;
+          }
+        },
+        deserialize(val) {
+          if (isSerializedAutoInterval(val)) {
+            return autoInterval;
+          }
+          return val;
+        },
       },
       {
         name: 'maxBars',

src/plugins/data/common/search/aggs/utils/get_number_histogram_interval.test.ts

@@ -0,0 +1,96 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { getNumberHistogramIntervalByDatatableColumn } from '.';
+import { BUCKET_TYPES } from '../buckets';
+
+describe('getNumberHistogramIntervalByDatatableColumn', () => {
+  it('returns nothing on column from other data source', () => {
+    expect(
+      getNumberHistogramIntervalByDatatableColumn({
+        id: 'test',
+        name: 'test',
+        meta: {
+          type: 'date',
+          source: 'essql',
+        },
+      })
+    ).toEqual(undefined);
+  });
+
+  it('returns nothing on non histogram column', () => {
+    expect(
+      getNumberHistogramIntervalByDatatableColumn({
+        id: 'test',
+        name: 'test',
+        meta: {
+          type: 'date',
+          source: 'esaggs',
+          sourceParams: {
+            type: BUCKET_TYPES.TERMS,
+          },
+        },
+      })
+    ).toEqual(undefined);
+  });
+
+  it('returns interval on resolved auto interval', () => {
+    expect(
+      getNumberHistogramIntervalByDatatableColumn({
+        id: 'test',
+        name: 'test',
+        meta: {
+          type: 'date',
+          source: 'esaggs',
+          sourceParams: {
+            type: BUCKET_TYPES.HISTOGRAM,
+            params: {
+              interval: 'auto$$$20',
+            },
+          },
+        },
+      })
+    ).toEqual(20);
+  });
+
+  it('returns interval on fixed interval', () => {
+    expect(
+      getNumberHistogramIntervalByDatatableColumn({
+        id: 'test',
+        name: 'test',
+        meta: {
+          type: 'date',
+          source: 'esaggs',
+          sourceParams: {
+            type: BUCKET_TYPES.HISTOGRAM,
+            params: {
+              interval: 7,
+            },
+          },
+        },
+      })
+    ).toEqual(7);
+  });
+
+  it('returns undefined if information is not available', () => {
+    expect(
+      getNumberHistogramIntervalByDatatableColumn({
+        id: 'test',
+        name: 'test',
+        meta: {
+          type: 'date',
+          source: 'esaggs',
+          sourceParams: {
+            type: BUCKET_TYPES.HISTOGRAM,
+            params: {},
+          },
+        },
+      })
+    ).toEqual(undefined);
+  });
+});

src/plugins/data/common/search/aggs/utils/get_number_histogram_interval.ts

@@ -0,0 +1,48 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { DatatableColumn } from 'src/plugins/expressions/common';
+import type { AggParamsHistogram } from '../buckets';
+import { BUCKET_TYPES } from '../buckets/bucket_agg_types';
+
+const SEPARATOR = '$$$';
+
+function parseSerializedInterval(interval: string | number) {
+  if (typeof interval === 'number') {
+    return interval;
+  }
+  if (interval === 'auto') {
+    return 'auto';
+  }
+  return Number(interval.split(SEPARATOR)[1]);
+}
+
+export function buildSerializedAutoInterval(usedInterval: number) {
+  return `auto${SEPARATOR}${usedInterval}`;
+}
+
+export function isSerializedAutoInterval(interval: string | number) {
+  return typeof interval === 'string' && interval.startsWith('auto');
+}
+
+/**
+ * Helper function returning the used interval for data table column created by the histogramm agg type.
+ * "auto" will get expanded to the actually used interval.
+ * If the column is not a column created by a histogram aggregation of the esaggs data source,
+ * this function will return undefined.
+ */
+export const getNumberHistogramIntervalByDatatableColumn = (column: DatatableColumn) => {
+  if (column.meta.source !== 'esaggs') return;
+  if (column.meta.sourceParams?.type !== BUCKET_TYPES.HISTOGRAM) return;
+  const params = (column.meta.sourceParams.params as unknown) as AggParamsHistogram;
+
+  if (!params.interval) {
+    return undefined;
+  }
+  return parseSerializedInterval(params.interval);
+};

src/plugins/data/common/search/aggs/utils/index.ts

@@ -7,6 +7,7 @@
  */
 
 export * from './calculate_auto_time_expression';
+export { getNumberHistogramIntervalByDatatableColumn } from './get_number_histogram_interval';
 export * from './date_interval_utils';
 export * from './get_format_with_aggs';
 export * from './ipv4_address';

src/plugins/data/public/index.ts

@@ -308,6 +308,7 @@ import {
   parseInterval,
   toAbsoluteDates,
   boundsDescendingRaw,
+  getNumberHistogramIntervalByDatatableColumn,
   // expressions utils
   getRequestInspectorStats,
   getResponseInspectorStats,
@@ -416,6 +417,7 @@ export const search = {
     termsAggFilter,
     toAbsoluteDates,
     boundsDescendingRaw,
+    getNumberHistogramIntervalByDatatableColumn,
   },
   getRequestInspectorStats,
   getResponseInspectorStats,