diff --git a/src/core_plugins/input_control_vis/public/control/create_search_source.js b/src/core_plugins/input_control_vis/public/control/create_search_source.js
index f00125c8ba757..87cf9da28ba0a 100644
--- a/src/core_plugins/input_control_vis/public/control/create_search_source.js
+++ b/src/core_plugins/input_control_vis/public/control/create_search_source.js
@@ -21,16 +21,16 @@
 export function createSearchSource(kbnApi, initialState, indexPattern, aggs, useTimeFilter, filters = []) {
   const searchSource = new kbnApi.SearchSource(initialState);
   // Do not not inherit from rootSearchSource to avoid picking up time and globals
-  searchSource.inherits(false);
-  searchSource.filter(() => {
+  searchSource.setParent(false);
+  searchSource.setField('filter', () => {
     const activeFilters = [...filters];
     if (useTimeFilter) {
       activeFilters.push(kbnApi.timeFilter.createFilter(indexPattern));
     }
     return activeFilters;
   });
-  searchSource.size(0);
-  searchSource.index(indexPattern);
-  searchSource.aggs(aggs);
+  searchSource.setField('size', 0);
+  searchSource.setField('index', indexPattern);
+  searchSource.setField('aggs', aggs);
   return searchSource;
 }
diff --git a/src/core_plugins/kibana/public/context/api/__tests__/_stubs.js b/src/core_plugins/kibana/public/context/api/__tests__/_stubs.js
index 2100745f54e73..53aa102864141 100644
--- a/src/core_plugins/kibana/public/context/api/__tests__/_stubs.js
+++ b/src/core_plugins/kibana/public/context/api/__tests__/_stubs.js
@@ -39,18 +39,17 @@ export function createSearchSourceStubProvider(hits, timeField) {
     }),
   };
 
-  searchSourceStub.filter = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.inherits = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.set = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.get = sinon.spy(key => {
-    const previousSetCall = searchSourceStub.set.withArgs(key).lastCall;
+  searchSourceStub.setParent = sinon.stub().returns(searchSourceStub);
+  searchSourceStub.setField = sinon.stub().returns(searchSourceStub);
+  searchSourceStub.getField = sinon.spy(key => {
+    const previousSetCall = searchSourceStub.setField.withArgs(key).lastCall;
     return previousSetCall ? previousSetCall.args[1] : null;
   });
   searchSourceStub.fetch = sinon.spy(() => {
     const timeField = searchSourceStub._stubTimeField;
-    const lastQuery = searchSourceStub.set.withArgs('query').lastCall.args[1];
+    const lastQuery = searchSourceStub.setField.withArgs('query').lastCall.args[1];
     const timeRange = lastQuery.query.constant_score.filter.range[timeField];
-    const lastSort = searchSourceStub.set.withArgs('sort').lastCall.args[1];
+    const lastSort = searchSourceStub.setField.withArgs('sort').lastCall.args[1];
     const sortDirection = lastSort[0][timeField];
     const sortFunction =
       sortDirection === 'asc'
diff --git a/src/core_plugins/kibana/public/context/api/__tests__/anchor.js b/src/core_plugins/kibana/public/context/api/__tests__/anchor.js
index 044e61d8608e2..1fd84edb43156 100644
--- a/src/core_plugins/kibana/public/context/api/__tests__/anchor.js
+++ b/src/core_plugins/kibana/public/context/api/__tests__/anchor.js
@@ -26,6 +26,24 @@ import { SearchSourceProvider } from 'ui/courier';
 
 import { fetchAnchorProvider } from '../anchor';
 
+function createSearchSourceStubProvider(hits) {
+  const searchSourceStub = {
+    _stubHits: hits,
+  };
+
+  searchSourceStub.setParent = sinon.stub().returns(searchSourceStub);
+  searchSourceStub.setField = sinon.stub().returns(searchSourceStub);
+  searchSourceStub.fetch = sinon.spy(() => Promise.resolve({
+    hits: {
+      hits: searchSourceStub._stubHits,
+      total: searchSourceStub._stubHits.length,
+    },
+  }));
+
+  return function SearchSourceStubProvider() {
+    return searchSourceStub;
+  };
+}
 
 describe('context app', function () {
   beforeEach(ngMock.module('kibana'));
@@ -61,9 +79,9 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const inheritsSpy = searchSourceStub.inherits;
-          expect(inheritsSpy.calledOnce).to.be(true);
-          expect(inheritsSpy.firstCall.args[0]).to.eql(false);
+          const setParentSpy = searchSourceStub.setParent;
+          expect(setParentSpy.calledOnce).to.be(true);
+          expect(setParentSpy.firstCall.args[0]).to.eql(false);
         });
     });
 
@@ -72,9 +90,8 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const setIndexSpy = searchSourceStub.set.withArgs('index');
-          expect(setIndexSpy.calledOnce).to.be(true);
-          expect(setIndexSpy.firstCall.args[1]).to.eql({ id: 'INDEX_PATTERN_ID' });
+          const setFieldSpy = searchSourceStub.setField;
+          expect(setFieldSpy.firstCall.args[1]).to.eql({ id: 'INDEX_PATTERN_ID' });
         });
     });
 
@@ -83,7 +100,7 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const setVersionSpy = searchSourceStub.set.withArgs('version');
+          const setVersionSpy = searchSourceStub.setField.withArgs('version');
           expect(setVersionSpy.calledOnce).to.be(true);
           expect(setVersionSpy.firstCall.args[1]).to.eql(true);
         });
@@ -94,7 +111,7 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const setSizeSpy = searchSourceStub.set.withArgs('size');
+          const setSizeSpy = searchSourceStub.setField.withArgs('size');
           expect(setSizeSpy.calledOnce).to.be(true);
           expect(setSizeSpy.firstCall.args[1]).to.eql(1);
         });
@@ -105,7 +122,7 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const setQuerySpy = searchSourceStub.set.withArgs('query');
+          const setQuerySpy = searchSourceStub.setField.withArgs('query');
           expect(setQuerySpy.calledOnce).to.be(true);
           expect(setQuerySpy.firstCall.args[1]).to.eql({
             query: {
@@ -128,7 +145,7 @@ describe('context app', function () {
 
       return fetchAnchor('INDEX_PATTERN_ID', 'doc', 'id', [{ '@timestamp': 'desc' }, { '_doc': 'asc' }])
         .then(() => {
-          const setSortSpy = searchSourceStub.set.withArgs('sort');
+          const setSortSpy = searchSourceStub.setField.withArgs('sort');
           expect(setSortSpy.calledOnce).to.be(true);
           expect(setSortSpy.firstCall.args[1]).to.eql([
             { '@timestamp': 'desc' },
@@ -167,23 +184,3 @@ describe('context app', function () {
     });
   });
 });
-
-function createSearchSourceStubProvider(hits) {
-  const searchSourceStub = {
-    _stubHits: hits,
-  };
-
-  searchSourceStub.filter = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.inherits = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.set = sinon.stub().returns(searchSourceStub);
-  searchSourceStub.fetch = sinon.spy(() => Promise.resolve({
-    hits: {
-      hits: searchSourceStub._stubHits,
-      total: searchSourceStub._stubHits.length,
-    },
-  }));
-
-  return function SearchSourceStubProvider() {
-    return searchSourceStub;
-  };
-}
diff --git a/src/core_plugins/kibana/public/context/api/__tests__/predecessors.js b/src/core_plugins/kibana/public/context/api/__tests__/predecessors.js
index e940468bcbcd9..2e461ff836fe6 100644
--- a/src/core_plugins/kibana/public/context/api/__tests__/predecessors.js
+++ b/src/core_plugins/kibana/public/context/api/__tests__/predecessors.js
@@ -95,7 +95,7 @@ describe('context app', function () {
         []
       )
         .then((hits) => {
-          const intervals = searchSourceStub.set.args
+          const intervals = searchSourceStub.setField.args
             .filter(([property]) => property === 'query')
             .map(([, { query }]) => _.get(query, ['constant_score', 'filter', 'range', '@timestamp']));
 
@@ -131,7 +131,7 @@ describe('context app', function () {
         []
       )
         .then((hits) => {
-          const intervals = searchSourceStub.set.args
+          const intervals = searchSourceStub.setField.args
             .filter(([property]) => property === 'query')
             .map(([, { query }]) => _.get(query, ['constant_score', 'filter', 'range', '@timestamp']));
 
@@ -177,9 +177,9 @@ describe('context app', function () {
         []
       )
         .then(() => {
-          const inheritsSpy = searchSourceStub.inherits;
-          expect(inheritsSpy.alwaysCalledWith(false)).to.be(true);
-          expect(inheritsSpy.called).to.be(true);
+          const setParentSpy = searchSourceStub.setParent;
+          expect(setParentSpy.alwaysCalledWith(false)).to.be(true);
+          expect(setParentSpy.called).to.be(true);
         });
     });
   });
diff --git a/src/core_plugins/kibana/public/context/api/__tests__/successors.js b/src/core_plugins/kibana/public/context/api/__tests__/successors.js
index bede78439a22f..1974d55655e25 100644
--- a/src/core_plugins/kibana/public/context/api/__tests__/successors.js
+++ b/src/core_plugins/kibana/public/context/api/__tests__/successors.js
@@ -95,7 +95,7 @@ describe('context app', function () {
         []
       )
         .then((hits) => {
-          const intervals = searchSourceStub.set.args
+          const intervals = searchSourceStub.setField.args
             .filter(([property]) => property === 'query')
             .map(([, { query }]) => _.get(query, ['constant_score', 'filter', 'range', '@timestamp']));
 
@@ -133,7 +133,7 @@ describe('context app', function () {
         []
       )
         .then((hits) => {
-          const intervals = searchSourceStub.set.args
+          const intervals = searchSourceStub.setField.args
             .filter(([property]) => property === 'query')
             .map(([, { query }]) => _.get(query, ['constant_score', 'filter', 'range', '@timestamp']));
 
@@ -179,9 +179,9 @@ describe('context app', function () {
         []
       )
         .then(() => {
-          const inheritsSpy = searchSourceStub.inherits;
-          expect(inheritsSpy.alwaysCalledWith(false)).to.be(true);
-          expect(inheritsSpy.called).to.be(true);
+          const setParentSpy = searchSourceStub.setParent;
+          expect(setParentSpy.alwaysCalledWith(false)).to.be(true);
+          expect(setParentSpy.called).to.be(true);
         });
     });
   });
diff --git a/src/core_plugins/kibana/public/context/api/anchor.js b/src/core_plugins/kibana/public/context/api/anchor.js
index 81d88f0394504..4c541845251f6 100644
--- a/src/core_plugins/kibana/public/context/api/anchor.js
+++ b/src/core_plugins/kibana/public/context/api/anchor.js
@@ -32,11 +32,11 @@ export function fetchAnchorProvider(indexPatterns, Private) {
   ) {
     const indexPattern = await indexPatterns.get(indexPatternId);
     const searchSource = new SearchSource()
-      .inherits(false)
-      .set('index', indexPattern)
-      .set('version', true)
-      .set('size', 1)
-      .set('query', {
+      .setParent(false)
+      .setField('index', indexPattern)
+      .setField('version', true)
+      .setField('size', 1)
+      .setField('query', {
         query: {
           constant_score: {
             filter: {
@@ -49,7 +49,7 @@ export function fetchAnchorProvider(indexPatterns, Private) {
         },
         language: 'lucene',
       })
-      .set('sort', sort);
+      .setField('sort', sort);
 
     const response = await searchSource.fetch();
 
diff --git a/src/core_plugins/kibana/public/context/api/context.js b/src/core_plugins/kibana/public/context/api/context.js
index d9446502e8e0c..68ca81e83a20e 100644
--- a/src/core_plugins/kibana/public/context/api/context.js
+++ b/src/core_plugins/kibana/public/context/api/context.js
@@ -33,8 +33,8 @@ import { reverseSortDirection } from './utils/sorting';
 /**
  * @typedef {Object} SearchSourceT
  * @prop {function(): Promise<SearchResult>} fetch
- * @prop {function(string, any): SearchSourceT} set
- * @prop {function(any): SearchSourceT} inherits
+ * @prop {function(string, any): SearchSourceT} setField
+ * @prop {function(any): SearchSourceT} setParent
  */
 
 /**
@@ -162,9 +162,9 @@ function fetchContextProvider(indexPatterns, Private) {
     const indexPattern = await indexPatterns.get(indexPatternId);
 
     return new SearchSource()
-      .inherits(false)
-      .set('index', indexPattern)
-      .set('filter', filters);
+      .setParent(false)
+      .setField('index', indexPattern)
+      .setField('filter', filters);
   }
 
   /**
@@ -209,8 +209,8 @@ function fetchContextProvider(indexPatterns, Private) {
     };
 
     const response = await searchSource
-      .set('size', maxCount)
-      .set('query', {
+      .setField('size', maxCount)
+      .setField('query', {
         query: {
           constant_score: {
             filter: {
@@ -225,15 +225,15 @@ function fetchContextProvider(indexPatterns, Private) {
         },
         language: 'lucene'
       })
-      .set('searchAfter', [
+      .setField('searchAfter', [
         afterTimeValue !== null ? afterTimeValue : startTimeValue,
         tieBreakerValue,
       ])
-      .set('sort', [
+      .setField('sort', [
         { [timeField]: timeSortDirection },
         { [tieBreakerField]: tieBreakerSortDirection },
       ])
-      .set('version', true)
+      .setField('version', true)
       .fetch();
 
     return response.hits ? response.hits.hits : [];
diff --git a/src/core_plugins/kibana/public/dashboard/__tests__/get_saved_dashboard_mock.js b/src/core_plugins/kibana/public/dashboard/__tests__/get_saved_dashboard_mock.js
index 8802683cb8453..d11436dead80c 100644
--- a/src/core_plugins/kibana/public/dashboard/__tests__/get_saved_dashboard_mock.js
+++ b/src/core_plugins/kibana/public/dashboard/__tests__/get_saved_dashboard_mock.js
@@ -24,7 +24,7 @@ export function getSavedDashboardMock(config) {
     title: 'my dashboard',
     panelsJSON: '[]',
     searchSource: {
-      getOwn: (param) => param
+      getOwnField: (param) => param
     }
   };
   return Object.assign(defaults, config);
diff --git a/src/core_plugins/kibana/public/dashboard/dashboard_state_manager.js b/src/core_plugins/kibana/public/dashboard/dashboard_state_manager.js
index ebdfb20cfaf8e..cafda9c386e68 100644
--- a/src/core_plugins/kibana/public/dashboard/dashboard_state_manager.js
+++ b/src/core_plugins/kibana/public/dashboard/dashboard_state_manager.js
@@ -579,8 +579,8 @@ export class DashboardStateManager {
    */
   applyFilters(query, filters) {
     this.appState.query = query;
-    this.savedDashboard.searchSource.set('query', query);
-    this.savedDashboard.searchSource.set('filter', filters);
+    this.savedDashboard.searchSource.setField('query', query);
+    this.savedDashboard.searchSource.setField('filter', filters);
     this.saveState();
   }
 
diff --git a/src/core_plugins/kibana/public/dashboard/lib/filter_utils.js b/src/core_plugins/kibana/public/dashboard/lib/filter_utils.js
index acb04a43390b0..cb5b88ca0c6e4 100644
--- a/src/core_plugins/kibana/public/dashboard/lib/filter_utils.js
+++ b/src/core_plugins/kibana/public/dashboard/lib/filter_utils.js
@@ -44,7 +44,7 @@ export class FilterUtils {
    * both query filters and filter bar filters.
    */
   static getDashboardFilters(dashboard) {
-    return dashboard.searchSource.getOwn('filter');
+    return dashboard.searchSource.getOwnField('filter');
   }
 
   /**
@@ -53,8 +53,8 @@ export class FilterUtils {
    * @returns {QueryFilter}
    */
   static getQueryFilterForDashboard(dashboard) {
-    if (dashboard.searchSource.getOwn('query')) {
-      return dashboard.searchSource.getOwn('query');
+    if (dashboard.searchSource.getOwnField('query')) {
+      return dashboard.searchSource.getOwnField('query');
     }
 
     const dashboardFilters = this.getDashboardFilters(dashboard);
diff --git a/src/core_plugins/kibana/public/discover/controllers/discover.js b/src/core_plugins/kibana/public/discover/controllers/discover.js
index 24177f1380a58..d7c6d982eb828 100644
--- a/src/core_plugins/kibana/public/discover/controllers/discover.js
+++ b/src/core_plugins/kibana/public/discover/controllers/discover.js
@@ -196,18 +196,17 @@ function discoverController(
   $scope.searchSource = savedSearch.searchSource;
   $scope.indexPattern = resolveIndexPatternLoading();
   $scope.searchSource
-    .set('index', $scope.indexPattern)
-    .highlightAll(true)
-    .version(true);
+    .setField('index', $scope.indexPattern)
+    .setField('highlightAll', true)
+    .setField('version', true);
 
   // searchSource which applies time range
-  const timeRangeSearchSource = savedSearch.searchSource.new();
-  timeRangeSearchSource.set('filter', () => {
+  const timeRangeSearchSource = savedSearch.searchSource.create();
+  timeRangeSearchSource.setField('filter', () => {
     return timefilter.createFilter($scope.indexPattern);
   });
 
-  $scope.searchSource.inherits(timeRangeSearchSource);
-
+  $scope.searchSource.setParent(timeRangeSearchSource);
 
   const pageTitleSuffix = savedSearch.id && savedSearch.title ? `: ${savedSearch.title}` : '';
   docTitle.change(`Discover${pageTitleSuffix}`);
@@ -258,26 +257,26 @@ function discoverController(
   };
 
   this.getSharingData = async () => {
-    const searchSource = $scope.searchSource.clone();
+    const searchSource = $scope.searchSource.createCopy();
 
     const { searchFields, selectFields } = await getSharingDataFields();
-    searchSource.set('fields', searchFields);
-    searchSource.set('sort', getSort($state.sort, $scope.indexPattern));
-    searchSource.set('highlight', null);
-    searchSource.set('highlightAll', null);
-    searchSource.set('aggs', null);
-    searchSource.set('size', null);
+    searchSource.setField('fields', searchFields);
+    searchSource.setField('sort', getSort($state.sort, $scope.indexPattern));
+    searchSource.setField('highlight', null);
+    searchSource.setField('highlightAll', null);
+    searchSource.setField('aggs', null);
+    searchSource.setField('size', null);
 
     const body = await searchSource.getSearchRequestBody();
     return {
       searchRequest: {
-        index: searchSource.get('index').title,
+        index: searchSource.getField('index').title,
         body
       },
       fields: selectFields,
       metaFields: $scope.indexPattern.metaFields,
       conflictedTypesFields: $scope.indexPattern.fields.filter(f => f.type === 'conflict').map(f => f.name),
-      indexPatternId: searchSource.get('index').id
+      indexPatternId: searchSource.getField('index').id
     };
   };
 
@@ -293,7 +292,7 @@ function discoverController(
 
   function getStateDefaults() {
     return {
-      query: $scope.searchSource.get('query') || {
+      query: $scope.searchSource.getField('query') || {
         query: '',
         language: localStorage.get('kibana.userQueryLanguage') || config.get('search:queryLanguage')
       },
@@ -301,7 +300,7 @@ function discoverController(
       columns: savedSearch.columns.length > 0 ? savedSearch.columns : config.get('defaultColumns').slice(),
       index: $scope.indexPattern.id,
       interval: 'auto',
-      filters: _.cloneDeep($scope.searchSource.getOwn('filter'))
+      filters: _.cloneDeep($scope.searchSource.getOwnField('filter'))
     };
   }
 
@@ -344,7 +343,7 @@ function discoverController(
           if (!sort) return;
 
           // get the current sort from {key: val} to ["key", "val"];
-          const currentSort = _.pairs($scope.searchSource.get('sort')).pop();
+          const currentSort = _.pairs($scope.searchSource.getField('sort')).pop();
 
           // if the searchSource doesn't know, tell it so
           if (!angular.equals(sort, currentSort)) $scope.fetch();
@@ -535,7 +534,11 @@ function discoverController(
     }
 
     $scope.updateTime();
-    if (sort[0] === '_score') segmented.setMaxSegments(1);
+
+    if (sort[0] === '_score') {
+      segmented.setMaxSegments(1);
+    }
+
     segmented.setDirection(sortBy === 'time' ? (sort[1] || 'desc') : 'desc');
     segmented.setSortFn(sortFn);
     segmented.setSize($scope.opts.sampleSize);
@@ -567,14 +570,14 @@ function discoverController(
           .resolve(responseHandler($scope.vis, merged))
           .then(resp => {
             $scope.visData = resp;
-            const visEl = $element.find('.visualization-container')[0];
+            const visEl = $element.find('#discoverHistogram')[0];
             visualizationLoader(visEl, $scope.vis, $scope.visData, $scope.uiState, { listenOnChange: true });
           });
       }
 
       $scope.hits = merged.hits.total;
 
-      const indexPattern = $scope.searchSource.get('index');
+      const indexPattern = $scope.searchSource.getField('index');
 
       // the merge rows, use a new array to help watchers
       $scope.rows = merged.hits.hits.slice();
@@ -646,10 +649,10 @@ function discoverController(
 
   $scope.updateDataSource = Promise.method(function updateDataSource() {
     $scope.searchSource
-      .size($scope.opts.sampleSize)
-      .sort(getSort($state.sort, $scope.indexPattern))
-      .query(!$state.query ? null : $state.query)
-      .set('filter', queryFilter.getFilters());
+      .setField('size', $scope.opts.sampleSize)
+      .setField('sort', getSort($state.sort, $scope.indexPattern))
+      .setField('query', !$state.query ? null : $state.query)
+      .setField('filter', queryFilter.getFilters());
   });
 
   $scope.setSortOrder = function setSortOrder(columnName, direction) {
@@ -731,7 +734,7 @@ function discoverController(
         return $scope.vis.getAggConfig().onSearchRequestStart(searchSource, searchRequest);
       });
 
-      $scope.searchSource.aggs(function () {
+      $scope.searchSource.setField('aggs', function () {
         return $scope.vis.getAggConfig().toDsl();
       });
     }
@@ -747,7 +750,7 @@ function discoverController(
     const stateVal = props.stateVal;
     const stateValFound = props.stateValFound;
 
-    const own = $scope.searchSource.getOwn('index');
+    const own = $scope.searchSource.getOwnField('index');
 
     if (own && !stateVal) return own;
     if (stateVal && !stateValFound) {
diff --git a/src/core_plugins/kibana/public/discover/embeddable/search_embeddable.js b/src/core_plugins/kibana/public/discover/embeddable/search_embeddable.js
index 47a94aa4e45ea..8b076ce825e2e 100644
--- a/src/core_plugins/kibana/public/discover/embeddable/search_embeddable.js
+++ b/src/core_plugins/kibana/public/discover/embeddable/search_embeddable.js
@@ -29,7 +29,7 @@ export class SearchEmbeddable extends Embeddable {
       metadata: {
         title: savedSearch.title,
         editUrl,
-        indexPattern: savedSearch.searchSource.get('index')
+        indexPattern: savedSearch.searchSource.getField('index')
       }
     });
     this.onEmbeddableStateChanged = onEmbeddableStateChanged;
@@ -58,8 +58,8 @@ export class SearchEmbeddable extends Embeddable {
     this.searchScope.sort = this.customization.sort || this.savedSearch.sort;
     this.searchScope.sharedItemTitle = this.panelTitle;
 
-    this.filtersSearchSource.set('filter', this.filters);
-    this.filtersSearchSource.set('query', this.query);
+    this.filtersSearchSource.setField('filter', this.filters);
+    this.filtersSearchSource.setField('query', this.query);
   }
 
   onContainerStateChanged(containerState) {
@@ -85,15 +85,15 @@ export class SearchEmbeddable extends Embeddable {
     this.searchScope.description = this.savedSearch.description;
     this.searchScope.searchSource = this.savedSearch.searchSource;
 
-    const timeRangeSearchSource = this.searchScope.searchSource.new();
-    timeRangeSearchSource.filter(() => {
-      return getTime(this.searchScope.searchSource.get('index'), this.timeRange);
+    const timeRangeSearchSource = this.searchScope.searchSource.create();
+    timeRangeSearchSource.setField('filter', () => {
+      return getTime(this.searchScope.searchSource.getField('index'), this.timeRange);
     });
 
-    this.filtersSearchSource = this.searchScope.searchSource.new();
-    this.filtersSearchSource.inherits(timeRangeSearchSource);
+    this.filtersSearchSource = this.searchScope.searchSource.create();
+    this.filtersSearchSource.setParent(timeRangeSearchSource);
 
-    this.searchScope.searchSource.inherits(this.filtersSearchSource);
+    this.searchScope.searchSource.setParent(this.filtersSearchSource);
 
     this.pushContainerStateParamsToScope();
 
@@ -103,14 +103,14 @@ export class SearchEmbeddable extends Embeddable {
     };
 
     this.searchScope.addColumn = (columnName) => {
-      this.savedSearch.searchSource.get('index').popularizeField(columnName, 1);
+      this.savedSearch.searchSource.getField('index').popularizeField(columnName, 1);
       columnActions.addColumn(this.searchScope.columns, columnName);
       this.searchScope.columns = this.customization.columns = this.searchScope.columns;
       this.emitEmbeddableStateChange(this.getEmbeddableState());
     };
 
     this.searchScope.removeColumn = (columnName) => {
-      this.savedSearch.searchSource.get('index').popularizeField(columnName, 1);
+      this.savedSearch.searchSource.getField('index').popularizeField(columnName, 1);
       columnActions.removeColumn(this.searchScope.columns, columnName);
       this.customization.columns = this.searchScope.columns;
       this.emitEmbeddableStateChange(this.getEmbeddableState());
@@ -123,7 +123,7 @@ export class SearchEmbeddable extends Embeddable {
     };
 
     this.searchScope.filter = (field, value, operator) => {
-      const index = this.savedSearch.searchSource.get('index').id;
+      const index = this.savedSearch.searchSource.getField('index').id;
       const stagedFilter = {
         field,
         value,
diff --git a/src/core_plugins/kibana/public/discover/index.html b/src/core_plugins/kibana/public/discover/index.html
index 589f99a66e192..a8fde71b987fb 100644
--- a/src/core_plugins/kibana/public/discover/index.html
+++ b/src/core_plugins/kibana/public/discover/index.html
@@ -48,7 +48,7 @@ <h1 tabindex="0" id="kui_local_breadcrumb" class="kuiLocalBreadcrumb">
           columns="state.columns"
           hits="rows"
           field-counts="fieldCounts"
-          index-pattern="searchSource.get('index')"
+          index-pattern="searchSource.getField('index')"
           index-pattern-list="opts.indexPatternList"
           state="state"
           on-add-field="addColumn"
@@ -129,7 +129,7 @@ <h2>Searching</h2>
 
               </header>
 
-              <div class="visualization-container"
+              <div id="discoverHistogram"
                  ng-if="vis && rows.length !== 0"
                  style="display: flex; height: 200px"
                 >
diff --git a/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/__tests__/flyout.test.js b/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/__tests__/flyout.test.js
index 0b2f03ba9801d..cd0cd57871028 100644
--- a/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/__tests__/flyout.test.js
+++ b/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/__tests__/flyout.test.js
@@ -163,7 +163,7 @@ describe('Flyout', () => {
         },
         obj: {
           searchSource: {
-            getOwn: () => 'MyIndexPattern*',
+            getOwnField: () => 'MyIndexPattern*',
           },
         },
       },
diff --git a/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/flyout.js b/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/flyout.js
index f4aa2cda9d5c5..a48623c5225cc 100644
--- a/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/flyout.js
+++ b/src/core_plugins/kibana/public/management/sections/objects/components/objects_table/components/flyout/flyout.js
@@ -144,7 +144,7 @@ export class Flyout extends Component {
     );
 
     const byId = groupBy(conflictedIndexPatterns, ({ obj }) =>
-      obj.searchSource.getOwn('index')
+      obj.searchSource.getOwnField('index')
     );
     const conflicts = Object.entries(byId).reduce(
       (accum, [existingIndexPatternId, list]) => {
diff --git a/src/core_plugins/kibana/public/management/sections/objects/lib/__tests__/resolve_saved_objects.test.js b/src/core_plugins/kibana/public/management/sections/objects/lib/__tests__/resolve_saved_objects.test.js
index b775551b234d3..acfb6d0040bb2 100644
--- a/src/core_plugins/kibana/public/management/sections/objects/lib/__tests__/resolve_saved_objects.test.js
+++ b/src/core_plugins/kibana/public/management/sections/objects/lib/__tests__/resolve_saved_objects.test.js
@@ -238,7 +238,7 @@ describe('resolveSavedObjects', () => {
         {
           obj: {
             searchSource: {
-              getOwn: () => '1',
+              getOwnField: () => '1',
             },
             hydrateIndexPattern,
             save,
@@ -247,7 +247,7 @@ describe('resolveSavedObjects', () => {
         {
           obj: {
             searchSource: {
-              getOwn: () => '3',
+              getOwnField: () => '3',
             },
             hydrateIndexPattern,
             save,
diff --git a/src/core_plugins/kibana/public/management/sections/objects/lib/resolve_saved_objects.js b/src/core_plugins/kibana/public/management/sections/objects/lib/resolve_saved_objects.js
index 257a1f3226052..f3976ec37e531 100644
--- a/src/core_plugins/kibana/public/management/sections/objects/lib/resolve_saved_objects.js
+++ b/src/core_plugins/kibana/public/management/sections/objects/lib/resolve_saved_objects.js
@@ -81,7 +81,7 @@ export async function resolveIndexPatternConflicts(
 ) {
   let importCount = 0;
   await awaitEachItemInParallel(conflictedIndexPatterns, async ({ obj }) => {
-    let oldIndexId = obj.searchSource.getOwn('index');
+    let oldIndexId = obj.searchSource.getOwnField('index');
     // Depending on the object, this can either be the raw id or the actual index pattern object
     if (typeof oldIndexId !== 'string') {
       oldIndexId = oldIndexId.id;
diff --git a/src/core_plugins/kibana/public/visualize/editor/editor.js b/src/core_plugins/kibana/public/visualize/editor/editor.js
index d70d836ba4a13..b0afb15197916 100644
--- a/src/core_plugins/kibana/public/visualize/editor/editor.js
+++ b/src/core_plugins/kibana/public/visualize/editor/editor.js
@@ -191,11 +191,11 @@ function VisEditor(
   const stateDefaults = {
     uiState: savedVis.uiStateJSON ? JSON.parse(savedVis.uiStateJSON) : {},
     linked: !!savedVis.savedSearchId,
-    query: searchSource.getOwn('query') || {
+    query: searchSource.getOwnField('query') || {
       query: '',
       language: localStorage.get('kibana.userQueryLanguage') || config.get('search:queryLanguage')
     },
-    filters: searchSource.getOwn('filter') || [],
+    filters: searchSource.getOwnField('filter') || [],
     vis: savedVisState
   };
 
@@ -252,7 +252,7 @@ function VisEditor(
     };
 
     $scope.$watchMulti([
-      'searchSource.get("index")',
+      'searchSource.getField("index")',
       'vis.type.options.showTimePicker',
     ], function ([index, requiresTimePicker]) {
       const showTimeFilter = Boolean((!index || index.timeFieldName) && requiresTimePicker);
@@ -279,8 +279,8 @@ function VisEditor(
     // update the searchSource when query updates
     $scope.fetch = function () {
       $state.save();
-      savedVis.searchSource.set('query', $state.query);
-      savedVis.searchSource.set('filter', $state.filters);
+      savedVis.searchSource.setField('query', $state.query);
+      savedVis.searchSource.setField('filter', $state.filters);
       $scope.vis.forceReload();
     };
 
@@ -348,23 +348,23 @@ function VisEditor(
     toastNotifications.addSuccess(`Unlinked from saved search '${savedVis.savedSearch.title}'`);
 
     $state.linked = false;
-    const parent = searchSource.getParent(true);
-    const parentsParent = parent.getParent(true);
+    const searchSourceParent = searchSource.getParent(true);
+    const searchSourceGrandparent = searchSourceParent.getParent(true);
 
     delete savedVis.savedSearchId;
-    parent.set('filter', _.union(searchSource.getOwn('filter'), parent.getOwn('filter')));
+    searchSourceParent.setField('filter', _.union(searchSource.getOwnField('filter'), searchSourceParent.getOwnField('filter')));
 
     // copy over all state except "aggs", "query" and "filter"
-    _(parent.toJSON())
+    _(searchSourceParent.toJSON())
       .omit(['aggs', 'filter', 'query'])
       .forOwn(function (val, key) {
-        searchSource.set(key, val);
+        searchSource.setField(key, val);
       })
       .commit();
 
-    $state.query = searchSource.get('query');
-    $state.filters = searchSource.get('filter');
-    searchSource.inherits(parentsParent);
+    $state.query = searchSource.getField('query');
+    $state.filters = searchSource.getField('filter');
+    searchSource.setParent(searchSourceGrandparent);
 
     $scope.fetch();
   };
diff --git a/src/core_plugins/kibana/public/visualize/saved_visualizations/_saved_vis.js b/src/core_plugins/kibana/public/visualize/saved_visualizations/_saved_vis.js
index e8d9dc19b5cc9..8909fabb97b33 100644
--- a/src/core_plugins/kibana/public/visualize/saved_visualizations/_saved_vis.js
+++ b/src/core_plugins/kibana/public/visualize/saved_visualizations/_saved_vis.js
@@ -95,7 +95,7 @@ uiModules
 
       return self._getLinkedSavedSearch()
         .then(function () {
-          self.searchSource.size(0);
+          self.searchSource.setField('size', 0);
 
           return self.vis ? self._updateVis() : self._createVis();
         });
@@ -111,7 +111,7 @@ uiModules
       }
 
       if (self.savedSearch) {
-        self.searchSource.inherits(self.savedSearch.searchSource.getParent());
+        self.searchSource.setParent(self.savedSearch.searchSource.getParent());
         self.savedSearch.destroy();
         self.savedSearch = null;
       }
@@ -120,7 +120,7 @@ uiModules
         return savedSearches.get(self.savedSearchId)
           .then(function (savedSearch) {
             self.savedSearch = savedSearch;
-            self.searchSource.inherits(self.savedSearch.searchSource);
+            self.searchSource.setParent(self.savedSearch.searchSource);
           });
       }
     });
@@ -137,7 +137,7 @@ uiModules
         self.visState.title = self.title;
       }
       self.vis = new Vis(
-        self.searchSource.get('index'),
+        self.searchSource.getField('index'),
         self.visState
       );
 
@@ -147,7 +147,7 @@ uiModules
     SavedVis.prototype._updateVis = function () {
       const self = this;
 
-      self.vis.indexPattern = self.searchSource.get('index');
+      self.vis.indexPattern = self.searchSource.getField('index');
       self.visState.title = self.title;
       self.vis.setState(self.visState);
     };
diff --git a/src/core_plugins/kibana/server/lib/export/collect_index_patterns.js b/src/core_plugins/kibana/server/lib/export/collect_index_patterns.js
index 1f1be4baf9ad2..441871208dc08 100644
--- a/src/core_plugins/kibana/server/lib/export/collect_index_patterns.js
+++ b/src/core_plugins/kibana/server/lib/export/collect_index_patterns.js
@@ -22,15 +22,15 @@ export async function collectIndexPatterns(savedObjectsClient, panels) {
     const { kibanaSavedObjectMeta, savedSearchId } = panel.attributes;
 
     if (kibanaSavedObjectMeta && kibanaSavedObjectMeta.searchSourceJSON && !savedSearchId) {
-      let searchSource;
+      let searchSourceData;
       try {
-        searchSource = JSON.parse(kibanaSavedObjectMeta.searchSourceJSON);
+        searchSourceData = JSON.parse(kibanaSavedObjectMeta.searchSourceJSON);
       } catch (err) {
         return acc;
       }
 
-      if (searchSource.index && !acc.find(s => s.id === searchSource.index)) {
-        acc.push({ type: 'index-pattern', id: searchSource.index });
+      if (searchSourceData.index && !acc.find(s => s.id === searchSourceData.index)) {
+        acc.push({ type: 'index-pattern', id: searchSourceData.index });
       }
     }
     return acc;
diff --git a/src/core_plugins/tile_map/public/coordinate_maps_visualization.js b/src/core_plugins/tile_map/public/coordinate_maps_visualization.js
index 8f8c18f9b83a0..3fec239c504c1 100644
--- a/src/core_plugins/tile_map/public/coordinate_maps_visualization.js
+++ b/src/core_plugins/tile_map/public/coordinate_maps_visualization.js
@@ -185,9 +185,9 @@ export function CoordinateMapsVisualizationProvider(Notifier, Private) {
     async getGeohashBounds() {
       const agg = this._getGeoHashAgg();
       if (agg) {
-        const searchSource = this.vis.searchSource.makeChild();
-        searchSource.size(0);
-        searchSource.aggs(function () {
+        const searchSource = this.vis.searchSource.createChild();
+        searchSource.setField('size', 0);
+        searchSource.setField('aggs', function () {
           const geoBoundsAgg = new AggConfig(agg.vis, {
             type: 'geo_bounds',
             enabled: true,
diff --git a/src/fixtures/stubbed_search_source.js b/src/fixtures/stubbed_search_source.js
index 5af4f37952130..3a36b97e6757e 100644
--- a/src/fixtures/stubbed_search_source.js
+++ b/src/fixtures/stubbed_search_source.js
@@ -27,16 +27,15 @@ export default function stubSearchSource(Private, $q, Promise) {
 
   let onResultsCount = 0;
   return {
-    sort: sinon.spy(),
-    size: sinon.spy(),
+    setField: sinon.spy(),
     fetch: sinon.spy(),
     destroy: sinon.spy(),
-    get: function (param) {
+    getField: function (param) {
       switch (param) {
         case 'index':
           return indexPattern;
         default:
-          throw new Error('Param "' + param + '" is not implemented in the stubbed search source');
+          throw new Error(`Param "${param}" is not implemented in the stubbed search source`);
       }
     },
     crankResults: function () {
diff --git a/src/ui/public/agg_types/buckets/histogram.js b/src/ui/public/agg_types/buckets/histogram.js
index fd553cbb7fb55..7fda6537de79e 100644
--- a/src/ui/public/agg_types/buckets/histogram.js
+++ b/src/ui/public/agg_types/buckets/histogram.js
@@ -70,9 +70,9 @@ export const histogramBucketAgg = new BucketAggType({
           : { field: field.name };
 
         return searchSource
-          .extend()
-          .size(0)
-          .aggs({
+          .createChild()
+          .setField('size', 0)
+          .setField('aggs', {
             maxAgg: {
               max: aggBody
             },
diff --git a/src/ui/public/agg_types/buckets/terms.js b/src/ui/public/agg_types/buckets/terms.js
index 30882aa929654..0c362fa9488ba 100644
--- a/src/ui/public/agg_types/buckets/terms.js
+++ b/src/ui/public/agg_types/buckets/terms.js
@@ -93,10 +93,10 @@ export const termsBucketAgg = new BucketAggType({
   },
   createFilter: createFilterTerms,
   postFlightRequest: async (resp, aggConfigs, aggConfig, searchSource) => {
-    const nestedSearchSource = searchSource.makeChild();
+    const nestedSearchSource = searchSource.createChild();
     if (aggConfig.params.otherBucket) {
       const filterAgg = buildOtherBucketAgg(aggConfigs, aggConfig, resp);
-      nestedSearchSource.set('aggs', filterAgg);
+      nestedSearchSource.setField('aggs', filterAgg);
 
       const request = aggConfigs.vis.API.inspectorAdapters.requests.start('Other bucket', {
         description: `This request counts the number of documents that fall
diff --git a/src/ui/public/courier/fetch/merge_duplicate_requests.js b/src/ui/public/courier/fetch/merge_duplicate_requests.js
index eb4cbc29bcb09..435971ed0bbf1 100644
--- a/src/ui/public/courier/fetch/merge_duplicate_requests.js
+++ b/src/ui/public/courier/fetch/merge_duplicate_requests.js
@@ -30,16 +30,16 @@ export function MergeDuplicatesRequestProvider(Private) {
     return requests.map(function (req) {
       if (!isRequest(req)) return req;
 
-      const iid = req.source._instanceid;
-      if (!index[iid]) {
+      const searchSourceId = req.source.getId();
+      if (!index[searchSourceId]) {
         // this request is unique so far
-        index[iid] = req;
+        index[searchSourceId] = req;
         // keep the request
         return req;
       }
 
       // the source was requested at least twice
-      req._uniq = index[iid];
+      req._uniq = index[searchSourceId];
       return DUPLICATE;
     });
   }
diff --git a/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.create_queue.js b/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.create_queue.js
index d83a11123f013..714bbb340969d 100644
--- a/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.create_queue.js
+++ b/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.create_queue.js
@@ -55,28 +55,28 @@ describe('SegmentedSearchRequest _createQueue', () => {
   });
 
   it('relies on indexPattern.toDetailedIndexList to generate queue', async function () {
-    const source = new MockSource();
-    const ip = source.get('index');
+    const searchSource = new MockSource();
+    const indexPattern = searchSource.getField('index');
     const indices = [1, 2, 3];
-    sinon.stub(ip, 'toDetailedIndexList').returns(Promise.resolve(indices));
+    sinon.stub(indexPattern, 'toDetailedIndexList').returns(Promise.resolve(indices));
 
-    const req = new SegmentedSearchRequest({ source, errorHandler: () => {} });
+    const req = new SegmentedSearchRequest({ source: searchSource, errorHandler: () => {} });
     const output = await req._createQueue();
     expect(output).to.equal(indices);
   });
 
   it('tells the index pattern its direction', async function () {
-    const source = new MockSource();
-    const ip = source.get('index');
-    const req = new SegmentedSearchRequest({ source, errorHandler: () => {} });
-    sinon.stub(ip, 'toDetailedIndexList').returns(Promise.resolve([1, 2, 3]));
+    const searchSource = new MockSource();
+    const indexPattern = searchSource.getField('index');
+    const req = new SegmentedSearchRequest({ source: searchSource, errorHandler: () => {} });
+    sinon.stub(indexPattern, 'toDetailedIndexList').returns(Promise.resolve([1, 2, 3]));
 
     req.setDirection('asc');
     await req._createQueue();
-    expect(ip.toDetailedIndexList.lastCall.args[2]).to.be('asc');
+    expect(indexPattern.toDetailedIndexList.lastCall.args[2]).to.be('asc');
 
     req.setDirection('desc');
     await req._createQueue();
-    expect(ip.toDetailedIndexList.lastCall.args[2]).to.be('desc');
+    expect(indexPattern.toDetailedIndexList.lastCall.args[2]).to.be('desc');
   });
 });
diff --git a/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.index_selection.js b/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.index_selection.js
index c73c217c2ec65..b1cc13d057f90 100644
--- a/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.index_selection.js
+++ b/src/ui/public/courier/fetch/request/segmented_search_request/__tests__/segmented_search_request.index_selection.js
@@ -50,8 +50,8 @@ describe('SegmentedSearchRequest index selection', function () {
   }));
 
   it('queries with size until all 500 docs returned', async function () {
-    const search = new MockSource();
-    const indexPattern = search.get('index');
+    const searchSource = new MockSource();
+    const indexPattern = searchSource.getField('index');
     sinon.stub(indexPattern, 'toDetailedIndexList').returns(Promise.resolve([
       { index: 'one', min: 0, max: 1 },
       { index: 'two', min: 0, max: 1 },
@@ -60,7 +60,7 @@ describe('SegmentedSearchRequest index selection', function () {
       { index: 'five', min: 0, max: 1 },
     ]));
 
-    const req = new SegmentedSearchRequest({ source: search, errorHandler: () => {} });
+    const req = new SegmentedSearchRequest({ source: searchSource, errorHandler: () => {} });
     req._handle.setDirection('desc');
     req._handle.setSortFn(new HitSortFn('desc'));
     req._handle.setSize(500);
@@ -96,8 +96,8 @@ describe('SegmentedSearchRequest index selection', function () {
   });
 
   it(`sets size 0 for indices that couldn't preclude hits`, async function () {
-    const search = new MockSource();
-    const indexPattern = search.get('index');
+    const searchSource = new MockSource();
+    const indexPattern = searchSource.getField('index');
 
     // the segreq is looking for 10 documents, and we will give it ten docs with time:5 in the first response.
     // on the second index it should still request 10 documents because it could produce documents with time:5.
@@ -111,7 +111,7 @@ describe('SegmentedSearchRequest index selection', function () {
       { index: 'five', min: 5, max: 50 },
     ]));
 
-    const req = new SegmentedSearchRequest({ source: search, errorHandler: () => {} });
+    const req = new SegmentedSearchRequest({ source: searchSource, errorHandler: () => {} });
     req._handle.setDirection('desc');
     req._handle.setSortFn(new HitSortFn('desc'));
     req._handle.setSize(10);
diff --git a/src/ui/public/courier/fetch/request/segmented_search_request/segmented_search_request.js b/src/ui/public/courier/fetch/request/segmented_search_request/segmented_search_request.js
index 244bc03720ab1..3245a0f03dee0 100644
--- a/src/ui/public/courier/fetch/request/segmented_search_request/segmented_search_request.js
+++ b/src/ui/public/courier/fetch/request/segmented_search_request/segmented_search_request.js
@@ -195,7 +195,7 @@ export function SegmentedSearchRequestProvider(Private, config) {
 
     _createQueue() {
       const timeBounds = timefilter.getBounds();
-      const indexPattern = this.source.get('index');
+      const indexPattern = this.source.getField('index');
       this._queueCreated = false;
 
       return indexPattern.toDetailedIndexList(timeBounds.min, timeBounds.max, this._direction)
@@ -298,7 +298,7 @@ export function SegmentedSearchRequestProvider(Private, config) {
 
     _detectHitsWindow(hits) {
       hits = hits || [];
-      const indexPattern = this.source.get('index');
+      const indexPattern = this.source.getField('index');
       const desiredSize = this._desiredSize;
 
       const size = _.size(hits);
diff --git a/src/ui/public/courier/saved_object/__tests__/saved_object.js b/src/ui/public/courier/saved_object/__tests__/saved_object.js
index 62c67ee26ee3f..957269b741257 100644
--- a/src/ui/public/courier/saved_object/__tests__/saved_object.js
+++ b/src/ui/public/courier/saved_object/__tests__/saved_object.js
@@ -432,11 +432,11 @@ describe('Saved Object', function () {
         });
 
         const savedObject = new SavedObject(config);
-        expect(!!savedObject.searchSource.get('index')).to.be(false);
+        expect(!!savedObject.searchSource.getField('index')).to.be(false);
 
         return savedObject.init().then(() => {
           expect(afterESRespCallback.called).to.be(true);
-          const index = savedObject.searchSource.get('index');
+          const index = savedObject.searchSource.getField('index');
           expect(index instanceof IndexPattern).to.be(true);
           expect(index.id).to.equal(indexPatternId);
         });
diff --git a/src/ui/public/courier/saved_object/saved_object.js b/src/ui/public/courier/saved_object/saved_object.js
index da035b9f5e7e8..1e50c53d70a53 100644
--- a/src/ui/public/courier/saved_object/saved_object.js
+++ b/src/ui/public/courier/saved_object/saved_object.js
@@ -112,23 +112,23 @@ export function SavedObjectProvider(Promise, Private, Notifier, confirmModalProm
     const parseSearchSource = (searchSourceJson) => {
       if (!this.searchSource) return;
 
-      // if we have a searchSource, set its state based on the searchSourceJSON field
-      let state;
+      // if we have a searchSource, set its values based on the searchSourceJson field
+      let searchSourceValues;
       try {
-        state = JSON.parse(searchSourceJson);
+        searchSourceValues = JSON.parse(searchSourceJson);
       } catch (e) {
-        state = {};
+        searchSourceValues = {};
       }
 
-      const oldState = this.searchSource.toJSON();
-      const fnProps = _.transform(oldState, function (dynamic, val, name) {
+      const searchSourceFields = this.searchSource.getFields();
+      const fnProps = _.transform(searchSourceFields, function (dynamic, val, name) {
         if (_.isFunction(val)) dynamic[name] = val;
       }, {});
 
-      this.searchSource.set(_.defaults(state, fnProps));
+      this.searchSource.setFields(_.defaults(searchSourceValues, fnProps));
 
-      if (!_.isUndefined(this.searchSource.getOwn('query'))) {
-        this.searchSource.set('query', migrateLegacyQuery(this.searchSource.getOwn('query')));
+      if (!_.isUndefined(this.searchSource.getOwnField('query'))) {
+        this.searchSource.setField('query', migrateLegacyQuery(this.searchSource.getOwnField('query')));
       }
     };
 
@@ -144,11 +144,11 @@ export function SavedObjectProvider(Promise, Private, Notifier, confirmModalProm
       }
 
       if (config.clearSavedIndexPattern) {
-        this.searchSource.set('index', undefined);
+        this.searchSource.setField('index', null);
         return Promise.resolve(null);
       }
 
-      let index = id || config.indexPattern || this.searchSource.getOwn('index');
+      let index = id || config.indexPattern || this.searchSource.getOwnField('index');
 
       if (!index) {
         return Promise.resolve(null);
@@ -162,7 +162,7 @@ export function SavedObjectProvider(Promise, Private, Notifier, confirmModalProm
       // At this point index will either be an IndexPattern, if cached, or a promise that
       // will return an IndexPattern, if not cached.
       return Promise.resolve(index).then(indexPattern => {
-        this.searchSource.set('index', indexPattern);
+        this.searchSource.setField('index', indexPattern);
       });
     };
 
@@ -260,8 +260,9 @@ export function SavedObjectProvider(Promise, Private, Notifier, confirmModalProm
       });
 
       if (this.searchSource) {
+        const searchSourceFields = _.omit(this.searchSource.getFields(), ['sort', 'size']);
         body.kibanaSavedObjectMeta = {
-          searchSourceJSON: angular.toJson(_.omit(this.searchSource.toJSON(), ['sort', 'size']))
+          searchSourceJSON: angular.toJson(searchSourceFields)
         };
       }
 
diff --git a/src/ui/public/courier/search_source/__tests__/search_source.js b/src/ui/public/courier/search_source/__tests__/search_source.js
index 694b2fb2cec08..a17cebccae23f 100644
--- a/src/ui/public/courier/search_source/__tests__/search_source.js
+++ b/src/ui/public/courier/search_source/__tests__/search_source.js
@@ -54,18 +54,18 @@ describe('SearchSource', function () {
 
   describe('#onResults()', function () {
     it('adds a request to the searchRequestQueue', function () {
-      const source = new SearchSource();
+      const searchSource = new SearchSource();
 
       expect(searchRequestQueue.getCount()).to.be(0);
-      source.onResults();
+      searchSource.onResults();
       expect(searchRequestQueue.getCount()).to.be(1);
     });
 
     it('returns a promise that is resolved with the results', function () {
-      const source = new SearchSource();
+      const searchSource = new SearchSource();
       const fakeResults = {};
 
-      const promise = source.onResults().then((results) => {
+      const promise = searchSource.onResults().then((results) => {
         expect(results).to.be(fakeResults);
       });
 
@@ -77,106 +77,132 @@ describe('SearchSource', function () {
 
   describe('#destroy()', function () {
     it('aborts all startable requests', function () {
-      const source = new SearchSource();
-      source.onResults();
+      const searchSource = new SearchSource();
+      searchSource.onResults();
       const searchRequest = searchRequestQueue.getSearchRequestAt(0);
       sinon.stub(searchRequest, 'canStart').returns(true);
-      source.destroy();
+      searchSource.destroy();
       expect(searchRequestQueue.getCount()).to.be(0);
     });
 
     it('aborts all non-startable requests', function () {
-      const source = new SearchSource();
-      source.onResults();
+      const searchSource = new SearchSource();
+      searchSource.onResults();
       const searchRequest = searchRequestQueue.getSearchRequestAt(0);
       sinon.stub(searchRequest, 'canStart').returns(false);
-      source.destroy();
+      searchSource.destroy();
       expect(searchRequestQueue.getCount()).to.be(0);
     });
   });
 
-  describe('#index()', function () {
+  describe('#setField()', function () {
+    it('sets the value for the property', function () {
+      const searchSource = new SearchSource();
+      searchSource.setField('aggs', 5);
+      expect(searchSource.getField('aggs')).to.be(5);
+    });
+
+    it('throws an error if the property is not accepted', function () {
+      const searchSource = new SearchSource();
+      expect(() => searchSource.setField('index', 5)).to.throwError();
+    });
+  });
+
+  describe('#getField()', function () {
+    it('gets the value for the property', function () {
+      const searchSource = new SearchSource();
+      searchSource.setField('aggs', 5);
+      expect(searchSource.getField('aggs')).to.be(5);
+    });
+
+    it('throws an error if the property is not accepted', function () {
+      const searchSource = new SearchSource();
+      expect(() => searchSource.getField('unacceptablePropName')).to.throwError();
+    });
+  });
+
+  describe(`#setField('index')`, function () {
     describe('auto-sourceFiltering', function () {
       describe('new index pattern assigned', function () {
-        it('generates a source filter', function () {
-          const source = new SearchSource();
-          expect(source.get('index')).to.be(undefined);
-          expect(source.get('source')).to.be(undefined);
-          source.set('index', indexPattern);
-          expect(source.get('index')).to.be(indexPattern);
-          expect(source.get('source')).to.be.a('function');
+        it('generates a searchSource filter', function () {
+          const searchSource = new SearchSource();
+          expect(searchSource.getField('index')).to.be(undefined);
+          expect(searchSource.getField('source')).to.be(undefined);
+          searchSource.setField('index', indexPattern);
+          expect(searchSource.getField('index')).to.be(indexPattern);
+          expect(searchSource.getField('source')).to.be.a('function');
         });
 
-        it('removes created source filter on removal', function () {
-          const source = new SearchSource();
-          source.set('index', indexPattern);
-          source.set('index', null);
-          expect(source.get('index')).to.be(undefined);
-          expect(source.get('source')).to.be(undefined);
+        it('removes created searchSource filter on removal', function () {
+          const searchSource = new SearchSource();
+          searchSource.setField('index', indexPattern);
+          searchSource.setField('index', null);
+          expect(searchSource.getField('index')).to.be(undefined);
+          expect(searchSource.getField('source')).to.be(undefined);
         });
       });
 
       describe('new index pattern assigned over another', function () {
-        it('replaces source filter with new', function () {
-          const source = new SearchSource();
-          source.set('index', indexPattern);
-          const sourceFilter1 = source.get('source');
-          source.set('index', indexPattern2);
-          expect(source.get('index')).to.be(indexPattern2);
-          expect(source.get('source')).to.be.a('function');
-          expect(source.get('source')).to.not.be(sourceFilter1);
+        it('replaces searchSource filter with new', function () {
+          const searchSource = new SearchSource();
+          searchSource.setField('index', indexPattern);
+          const searchSourceFilter1 = searchSource.getField('source');
+          searchSource.setField('index', indexPattern2);
+          expect(searchSource.getField('index')).to.be(indexPattern2);
+          expect(searchSource.getField('source')).to.be.a('function');
+          expect(searchSource.getField('source')).to.not.be(searchSourceFilter1);
         });
 
-        it('removes created source filter on removal', function () {
-          const source = new SearchSource();
-          source.set('index', indexPattern);
-          source.set('index', indexPattern2);
-          source.set('index', null);
-          expect(source.get('index')).to.be(undefined);
-          expect(source.get('source')).to.be(undefined);
+        it('removes created searchSource filter on removal', function () {
+          const searchSource = new SearchSource();
+          searchSource.setField('index', indexPattern);
+          searchSource.setField('index', indexPattern2);
+          searchSource.setField('index', null);
+          expect(searchSource.getField('index')).to.be(undefined);
+          expect(searchSource.getField('source')).to.be(undefined);
         });
       });
 
-      describe('ip assigned before custom source filter', function () {
-        it('custom source filter becomes new source', function () {
-          const source = new SearchSource();
+      describe('ip assigned before custom searchSource filter', function () {
+        it('custom searchSource filter becomes new searchSource', function () {
+          const searchSource = new SearchSource();
           const football = {};
-          source.set('index', indexPattern);
-          expect(source.get('source')).to.be.a('function');
-          source.set('source', football);
-          expect(source.get('index')).to.be(indexPattern);
-          expect(source.get('source')).to.be(football);
+          searchSource.setField('index', indexPattern);
+          expect(searchSource.getField('source')).to.be.a('function');
+          searchSource.setField('source', football);
+          expect(searchSource.getField('index')).to.be(indexPattern);
+          expect(searchSource.getField('source')).to.be(football);
         });
 
-        it('custom source stays after removal', function () {
-          const source = new SearchSource();
+        it('custom searchSource stays after removal', function () {
+          const searchSource = new SearchSource();
           const football = {};
-          source.set('index', indexPattern);
-          source.set('source', football);
-          source.set('index', null);
-          expect(source.get('index')).to.be(undefined);
-          expect(source.get('source')).to.be(football);
+          searchSource.setField('index', indexPattern);
+          searchSource.setField('source', football);
+          searchSource.setField('index', null);
+          expect(searchSource.getField('index')).to.be(undefined);
+          expect(searchSource.getField('source')).to.be(football);
         });
       });
 
-      describe('ip assigned after custom source filter', function () {
+      describe('ip assigned after custom searchSource filter', function () {
         it('leaves the custom filter in place', function () {
-          const source = new SearchSource();
+          const searchSource = new SearchSource();
           const football = {};
-          source.set('source', football);
-          source.set('index', indexPattern);
-          expect(source.get('index')).to.be(indexPattern);
-          expect(source.get('source')).to.be(football);
+          searchSource.setField('source', football);
+          searchSource.setField('index', indexPattern);
+          expect(searchSource.getField('index')).to.be(indexPattern);
+          expect(searchSource.getField('source')).to.be(football);
         });
 
-        it('custom source stays after removal', function () {
-          const source = new SearchSource();
+        it('custom searchSource stays after removal', function () {
+          const searchSource = new SearchSource();
           const football = {};
-          source.set('source', football);
-          source.set('index', indexPattern);
-          source.set('index', null);
-          expect(source.get('index')).to.be(undefined);
-          expect(source.get('source')).to.be(football);
+          searchSource.setField('source', football);
+          searchSource.setField('index', indexPattern);
+          searchSource.setField('index', null);
+          expect(searchSource.getField('index')).to.be(undefined);
+          expect(searchSource.getField('source')).to.be(football);
         });
       });
     });
@@ -184,66 +210,66 @@ describe('SearchSource', function () {
 
   describe('#onRequestStart()', () => {
     it('should be called when starting a request', async () => {
-      const source = new SearchSource();
+      const searchSource = new SearchSource();
       const fn = sinon.spy();
-      source.onRequestStart(fn);
+      searchSource.onRequestStart(fn);
       const request = {};
-      source.requestIsStarting(request);
+      searchSource.requestIsStarting(request);
       await timeout();
-      expect(fn.calledWith(source, request)).to.be(true);
+      expect(fn.calledWith(searchSource, request)).to.be(true);
     });
 
     it('should not be called on parent searchSource', async () => {
       const parent = new SearchSource();
-      const source = new SearchSource().inherits(parent);
+      const searchSource = new SearchSource().setParent(parent);
 
       const fn = sinon.spy();
-      source.onRequestStart(fn);
+      searchSource.onRequestStart(fn);
       const parentFn = sinon.spy();
       parent.onRequestStart(parentFn);
       const request = {};
-      source.requestIsStarting(request);
+      searchSource.requestIsStarting(request);
       await timeout();
-      expect(fn.calledWith(source, request)).to.be(true);
+      expect(fn.calledWith(searchSource, request)).to.be(true);
       expect(parentFn.notCalled).to.be(true);
     });
 
     it('should be called on parent searchSource if callParentStartHandlers is true', async () => {
       const parent = new SearchSource();
-      const source = new SearchSource().inherits(parent, { callParentStartHandlers: true });
+      const searchSource = new SearchSource().setParent(parent, { callParentStartHandlers: true });
 
       const fn = sinon.spy();
-      source.onRequestStart(fn);
+      searchSource.onRequestStart(fn);
       const parentFn = sinon.spy();
       parent.onRequestStart(parentFn);
       const request = {};
-      source.requestIsStarting(request);
+      searchSource.requestIsStarting(request);
       await timeout();
-      expect(fn.calledWith(source, request)).to.be(true);
-      expect(parentFn.calledWith(source, request)).to.be(true);
+      expect(fn.calledWith(searchSource, request)).to.be(true);
+      expect(parentFn.calledWith(searchSource, request)).to.be(true);
     });
   });
 
   describe('#_mergeProp', function () {
     describe('filter', function () {
-      let source;
+      let searchSource;
       let state;
 
       beforeEach(function () {
-        source = new SearchSource();
+        searchSource = new SearchSource();
         state = {};
       });
 
       [null, undefined].forEach(falsyValue => {
         it(`ignores ${falsyValue} filter`, function () {
-          source._mergeProp(state, falsyValue, 'filter');
+          searchSource._mergeProp(state, falsyValue, 'filter');
           expect(state.filters).to.be(undefined);
         });
       });
 
       [false, 0, '', NaN].forEach(falsyValue => {
         it(`doesn't add ${falsyValue} filter`, function () {
-          source._mergeProp(state, falsyValue, 'filter');
+          searchSource._mergeProp(state, falsyValue, 'filter');
           expect(state.filters).to.be.empty();
         });
       });
@@ -252,7 +278,7 @@ describe('SearchSource', function () {
         const filter = {
           meta: {}
         };
-        source._mergeProp(state, filter, 'filter');
+        searchSource._mergeProp(state, filter, 'filter');
         expect(state.filters).to.eql([filter]);
       });
 
@@ -262,7 +288,7 @@ describe('SearchSource', function () {
             disabled: false
           }
         };
-        source._mergeProp(state, filter, 'filter');
+        searchSource._mergeProp(state, filter, 'filter');
         expect(state.filters).to.eql([filter]);
       });
 
@@ -272,7 +298,7 @@ describe('SearchSource', function () {
             disabled: true
           }
         };
-        source._mergeProp(state, filter, 'filter');
+        searchSource._mergeProp(state, filter, 'filter');
         expect(state.filters).to.be.empty();
       });
 
@@ -289,7 +315,7 @@ describe('SearchSource', function () {
               byName: {}
             }
           };
-          source._mergeProp(state, filter, 'filter');
+          searchSource._mergeProp(state, filter, 'filter');
           expect(state.filters).to.eql([ filter ]);
         });
       });
@@ -307,7 +333,7 @@ describe('SearchSource', function () {
               byName: {}
             }
           };
-          source._mergeProp(state, filter, 'filter');
+          searchSource._mergeProp(state, filter, 'filter');
           expect(state.filters).to.be.empty();
         });
 
@@ -325,20 +351,10 @@ describe('SearchSource', function () {
               }
             }
           };
-          source._mergeProp(state, filter, 'filter');
+          searchSource._mergeProp(state, filter, 'filter');
           expect(state.filters).to.eql([ filter ]);
         });
       });
-
-      it('uses custom filter predicate', function () {
-        source.addFilterPredicate(() => {
-          return false;
-        });
-
-        const filter = {};
-        source._mergeProp(state, filter, 'filter');
-        expect(state.filters).to.be.empty();
-      });
     });
   });
 });
diff --git a/src/ui/public/courier/search_source/search_source.js b/src/ui/public/courier/search_source/search_source.js
index fa70082a30d1e..3a56d6a1dbf54 100644
--- a/src/ui/public/courier/search_source/search_source.js
+++ b/src/ui/public/courier/search_source/search_source.js
@@ -84,14 +84,31 @@ import { FieldWildcardProvider } from '../../field_wildcard';
 import { getHighlightRequest } from '../../../../core_plugins/kibana/common/highlight';
 import { BuildESQueryProvider } from './build_query';
 
-function parseInitialState(initialState) {
-  if (!initialState) {
+const FIELDS = [
+  'type',
+  'query',
+  'filter',
+  'sort',
+  'highlight',
+  'highlightAll',
+  'aggs',
+  'from',
+  'searchAfter',
+  'size',
+  'source',
+  'version',
+  'fields',
+  'index',
+];
+
+function parseInitialFields(initialFields) {
+  if (!initialFields) {
     return {};
   }
 
-  return typeof initialState === 'string' ?
-    JSON.parse(initialState)
-    : _.cloneDeep(initialState);
+  return typeof initialFields === 'string' ?
+    JSON.parse(initialFields)
+    : _.cloneDeep(initialFields);
 }
 
 function isIndexPattern(val) {
@@ -110,45 +127,11 @@ export function SearchSourceProvider(Promise, Private, config) {
   const forIp = Symbol('for which index pattern?');
 
   class SearchSource {
-    constructor(initialState) {
-      this._instanceid = _.uniqueId('data_source');
+    constructor(initialFields) {
+      this._id = _.uniqueId('data_source');
 
-      this._state = parseInitialState(initialState);
-
-      /**
-       * List of the editable state properties that turn into a
-       * chainable API
-       *
-       * @type {Array}
-       */
-      this._methods = [
-        'type',
-        'query',
-        'filter',
-        'sort',
-        'highlight',
-        'highlightAll',
-        'aggs',
-        'from',
-        'searchAfter',
-        'size',
-        'source',
-        'version',
-        'fields'
-      ];
-
-      // set internal state values
-      this._methods.forEach(name => {
-        this[name] = val => {
-          if (val == null) {
-            delete this._state[name];
-          } else {
-            this._state[name] = val;
-          }
-
-          return this;
-        };
-      });
+      this._fields = parseInitialFields(initialFields);
+      this._parent = undefined;
 
       this.history = [];
       this._requestStartHandlers = [];
@@ -163,13 +146,13 @@ export function SearchSourceProvider(Promise, Private, config) {
           const disabled = _.get(filter, 'meta.disabled');
           return disabled === undefined || disabled === false;
         },
-        (filter, state) => {
+        (filter, data) => {
           if (!config.get('courier:ignoreFilterIfFieldNotInIndex')) {
             return true;
           }
 
-          if ('meta' in filter && 'index' in state) {
-            const field = state.index.fields.byName[filter.meta.key];
+          if ('meta' in filter && 'index' in data) {
+            const field = data.index.fields.byName[filter.meta.key];
             if (!field) return false;
           }
           return true;
@@ -181,210 +164,136 @@ export function SearchSourceProvider(Promise, Private, config) {
      * PUBLIC API
      *****/
 
+    setFields(newFields) {
+      this._fields = newFields;
+      return this;
+    }
 
-    index(indexPattern) {
-      const state = this._state;
-
-      const hasSource = state.source;
-      const sourceCameFromIp = hasSource && state.source.hasOwnProperty(forIp);
-      const sourceIsForOurIp = sourceCameFromIp && state.source[forIp] === state.index;
-      if (sourceIsForOurIp) {
-        delete state.source;
+    setField = (field, value) => {
+      if (!FIELDS.includes(field)) {
+        throw new Error(`Can't set field '${field}' on SearchSource. Acceptable fields are: ${FIELDS.join(', ')}.`);
       }
 
-      if (indexPattern === undefined) return state.index;
-      if (indexPattern === null) return delete state.index;
-      if (!isIndexPattern(indexPattern)) {
-        throw new TypeError('expected indexPattern to be an IndexPattern duck.');
+      if (field === 'index') {
+        const fields = this._fields;
+
+        const hasSource = fields.source;
+        const sourceCameFromIp = hasSource && fields.source.hasOwnProperty(forIp);
+        const sourceIsForOurIp = sourceCameFromIp && fields.source[forIp] === fields.index;
+        if (sourceIsForOurIp) {
+          delete fields.source;
+        }
+
+        if (value === null || value === undefined) {
+          delete fields.index;
+          return this;
+        }
+
+        if (!isIndexPattern(value)) {
+          throw new TypeError('expected indexPattern to be an IndexPattern duck.');
+        }
+
+        fields[field] = value;
+        if (!fields.source) {
+          // imply source filtering based on the index pattern, but allow overriding
+          // it by simply setting another field for "source". When index is changed
+          fields.source = function () {
+            return value.getSourceFiltering();
+          };
+          fields.source[forIp] = value;
+        }
+
+        return this;
       }
 
-      state.index = indexPattern;
-      if (!state.source) {
-        // imply source filtering based on the index pattern, but allow overriding
-        // it by simply setting another value for "source". When index is changed
-        state.source = function () {
-          return indexPattern.getSourceFiltering();
-        };
-        state.source[forIp] = indexPattern;
+      if (value == null) {
+        delete this._fields[field];
+        return this;
       }
 
+      this._fields[field] = value;
       return this;
-    }
+    };
 
-    /**
-     * Set a searchSource that this source should inherit from
-     * @param  {SearchSource} searchSource - the parent searchSource
-     * @return {this} - chainable
-     */
-    inherits(parent, options = {}) {
-      this._parent = parent;
-      this._inheritOptions = options;
-      return this;
+    getId() {
+      return this._id;
     }
 
-    /**
-     * Get the parent of this SearchSource
-     * @return {undefined|searchSource}
-     */
-    getParent() {
-      return this._parent || undefined;
+    getFields() {
+      return _.clone(this._fields);
     }
 
     /**
-     * Temporarily prevent this Search from being fetched... not a fan but it's easy
+     * Get fields from the fields
      */
-    disable() {
-      this._fetchDisabled = true;
-    }
+    getField = field => {
+      if (!FIELDS.includes(field)) {
+        throw new Error(`Can't get field '${field}' from SearchSource. Acceptable fields are: ${FIELDS.join(', ')}.`);
+      }
 
-    /**
-     * Reverse of SearchSource#disable(), only need to call this if source was previously disabled
-     */
-    enable() {
-      this._fetchDisabled = false;
-    }
+      let searchSource = this;
 
-    onBeginSegmentedFetch(initFunction) {
-      const self = this;
-      return new Promise((resolve, reject) => {
-        function addRequest() {
-          const defer = Promise.defer();
-          const errorHandler = (request, error) => {
-            reject(error);
-            request.abort();
-          };
-          const req = new SegmentedSearchRequest({ source: self, defer, errorHandler, initFn: initFunction });
-
-          // Return promises created by the completion handler so that
-          // errors will bubble properly
-          return req.getCompletePromise().then(addRequest);
+      while (searchSource) {
+        const value = searchSource._fields[field];
+        if (value !== void 0) {
+          return value;
         }
 
-        addRequest();
-      });
-    }
-
-    addFilterPredicate(predicate) {
-      this._filterPredicates.push(predicate);
-    }
-
-    clone() {
-      const clone = new SearchSource(this.toString());
-      // when serializing the internal state with .toString() we lose the internal classes used in the index
-      // pattern, so we have to set it again to workaround this behavior
-      clone.set('index', this.get('index'));
-      clone.inherits(this.getParent());
-      return clone;
-    }
-
-    makeChild(params) {
-      return new SearchSource().inherits(this, params);
-    }
-
-    new() {
-      return new SearchSource();
-    }
-
-    async getSearchRequestBody() {
-      const searchRequest = await this._flatten();
-      return searchRequest.body;
-    }
+        searchSource = searchSource.getParent();
+      }
+    };
 
     /**
-     *  Called by requests of this search source when they are done
-     *  @param  {Courier.Request} request
-     *  @return {undefined}
+     * Get the field from our own fields, don't traverse up the chain
      */
-    requestIsStopped() {
-      this.activeFetchCount -= 1;
-    }
+    getOwnField(field) {
+      if (!FIELDS.includes(field)) {
+        throw new Error(`Can't get field '${field}' from SearchSource. Acceptable fields are: ${FIELDS.join(', ')}.`);
+      }
 
-    /**
-     * Get values from the state
-     * @param {string} name - The name of the property desired
-     * @return {any} - the value found
-     */
-    get(name) {
-      let self = this;
-      while (self) {
-        if (self._state[name] !== void 0) return self._state[name];
-        self = self.getParent();
+      const value = this._fields[field];
+      if (value !== void 0) {
+        return value;
       }
     }
 
-    /**
-     * Get the value from our own state, don't traverse up the chain
-     * @param {string} name - The name of the property desired
-     * @return {any} - the value found
-     */
-    getOwn(name) {
-      if (this._state[name] !== void 0) return this._state[name];
+    create() {
+      return new SearchSource();
     }
 
-    /**
-     * Change the entire state of a SearchSource
-     * @param {object|string} state - The SearchSource's new state, or a
-     *   string of the state value to set
-     */
-    set(state, val) {
-      const self = this;
-
-      if (typeof state === 'string') {
-        // the getter and setter methods check for undefined explicitly
-        // to identify getters and null to identify deletion
-        if (val === undefined) {
-          val = null;
-        }
-        self[state](val);
-      } else {
-        self._state = state;
-      }
-      return self;
+    createCopy() {
+      const json = angular.toJson(this._fields);
+      const newSearchSource = new SearchSource(json);
+      // when serializing the internal fields we lose the internal classes used in the index
+      // pattern, so we have to set it again to workaround this behavior
+      newSearchSource.setField('index', this.getField('index'));
+      newSearchSource.setParent(this.getParent());
+      return newSearchSource;
     }
 
-    /**
-     * Create a new dataSource object of the same type
-     * as this, which inherits this dataSource's properties
-     * @return {SearchSource}
-     */
-    extend() {
-      return new SearchSource().inherits(this);
+    createChild(options = {}) {
+      const childSearchSource = new SearchSource();
+      childSearchSource.setParent(this, options);
+      return childSearchSource;
     }
 
     /**
-     * return a simple, encodable object representing the state of the SearchSource
-     * @return {[type]} [description]
-     */
-    toJSON = function () {
-      return _.clone(this._state);
-    };
-
-    /**
-     * Create a string representation of the object
-     * @return {[type]} [description]
+     * Set a searchSource that this source should inherit from
+     * @param  {SearchSource} searchSource - the parent searchSource
+     * @return {this} - chainable
      */
-    toString() {
-      return angular.toJson(this.toJSON());
+    setParent(parent, options = {}) {
+      this._parent = parent;
+      this._inheritOptions = options;
+      return this;
     }
 
     /**
-     * Put a request in to the courier that this Source should
-     * be fetched on the next run of the courier
-     * @return {Promise}
+     * Get the parent of this SearchSource
+     * @return {undefined|searchSource}
      */
-    onResults() {
-      const self = this;
-
-      return new Promise(function (resolve, reject) {
-        const defer = Promise.defer();
-        defer.promise.then(resolve, reject);
-
-        const errorHandler = (request, error) => {
-          reject(error);
-          request.abort();
-        };
-        self._createRequest({ defer, errorHandler });
-      });
+    getParent() {
+      return this._parent || undefined;
     }
 
     /**
@@ -417,7 +326,7 @@ export function SearchSourceProvider(Promise, Private, config) {
     }
 
     /**
-     * Cancel all pending requests for this dataSource
+     * Cancel all pending requests for this searchSource
      * @return {undefined}
      */
     cancelQueued() {
@@ -426,15 +335,6 @@ export function SearchSourceProvider(Promise, Private, config) {
         .forEach(req => req.abort());
     }
 
-    /**
-     * Completely destroy the SearchSource.
-     * @return {undefined}
-     */
-    destroy() {
-      this.cancelQueued();
-      this._requestStartHandlers.length = 0;
-    }
-
     /**
      *  Add a handler that will be notified whenever requests start
      *  @param  {Function} handler
@@ -469,6 +369,68 @@ export function SearchSourceProvider(Promise, Private, config) {
         .then(_.noop);
     }
 
+    /**
+     * Put a request in to the courier that this Source should
+     * be fetched on the next run of the courier
+     * @return {Promise}
+     */
+    onResults() {
+      const self = this;
+
+      return new Promise(function (resolve, reject) {
+        const defer = Promise.defer();
+        defer.promise.then(resolve, reject);
+
+        const errorHandler = (request, error) => {
+          reject(error);
+          request.abort();
+        };
+        self._createRequest({ defer, errorHandler });
+      });
+    }
+
+    onBeginSegmentedFetch(initFunction) {
+      const self = this;
+      return new Promise((resolve, reject) => {
+        function addRequest() {
+          const defer = Promise.defer();
+          const errorHandler = (request, error) => {
+            reject(error);
+            request.abort();
+          };
+          const req = new SegmentedSearchRequest({ source: self, defer, errorHandler, initFn: initFunction });
+
+          // Return promises created by the completion handler so that
+          // errors will bubble properly
+          return req.getCompletePromise().then(addRequest);
+        }
+
+        addRequest();
+      });
+    }
+
+    async getSearchRequestBody() {
+      const searchRequest = await this._flatten();
+      return searchRequest.body;
+    }
+
+    /**
+     *  Called by requests of this search source when they are done
+     *  @param  {Courier.Request} request
+     *  @return {undefined}
+     */
+    requestIsStopped() {
+      this.activeFetchCount -= 1;
+    }
+
+    /**
+     * Completely destroy the SearchSource.
+     * @return {undefined}
+     */
+    destroy() {
+      this.cancelQueued();
+      this._requestStartHandlers.length = 0;
+    }
 
     /******
      * PRIVATE APIS
@@ -480,14 +442,6 @@ export function SearchSourceProvider(Promise, Private, config) {
         .filter(req => req.source === this);
     }
 
-    /**
-     * Gets the type of the DataSource
-     * @return {string}
-     */
-    _getType() {
-      return 'search';
-    }
-
     /**
      * Create a common search request object, which should
      * be put into the pending request queue, for this search
@@ -502,20 +456,20 @@ export function SearchSourceProvider(Promise, Private, config) {
     }
 
     /**
-     * Used to merge properties into the state within ._flatten().
-     * The state is passed in and modified by the function
+     * Used to merge properties into the data within ._flatten().
+     * The data is passed in and modified by the function
      *
-     * @param  {object} state - the current merged state
+     * @param  {object} data - the current merged data
      * @param  {*} val - the value at `key`
      * @param  {*} key - The key of `val`
      * @return {undefined}
      */
-    _mergeProp(state, val, key) {
+    _mergeProp(data, val, key) {
       if (typeof val === 'function') {
         const source = this;
         return Promise.cast(val(this))
           .then(function (newVal) {
-            return source._mergeProp(state, newVal, key);
+            return source._mergeProp(data, newVal, key);
           });
       }
 
@@ -526,17 +480,17 @@ export function SearchSourceProvider(Promise, Private, config) {
           let filters = Array.isArray(val) ? val : [val];
 
           filters = filters.filter(filter => {
-            return this._filterPredicates.every(predicate => predicate(filter, state));
+            return this._filterPredicates.every(predicate => predicate(filter, data));
           });
 
-          state.filters = [...(state.filters || []), ...filters];
+          data.filters = [...(data.filters || []), ...filters];
           return;
         case 'index':
         case 'type':
         case 'id':
         case 'highlightAll':
-          if (key && state[key] == null) {
-            state[key] = val;
+          if (key && data[key] == null) {
+            data[key] = val;
           }
           return;
         case 'searchAfter':
@@ -548,14 +502,14 @@ export function SearchSourceProvider(Promise, Private, config) {
           addToBody();
           break;
         case 'sort':
-          val = normalizeSortRequest(val, this.get('index'));
+          val = normalizeSortRequest(val, this.getField('index'));
           addToBody();
           break;
         case 'query':
-          state.query = (state.query || []).concat(val);
+          data.query = (data.query || []).concat(val);
           break;
         case 'fields':
-          state[key] = _.uniq([...(state[key] || []), ...val]);
+          data[key] = _.uniq([...(data[key] || []), ...val]);
           break;
         default:
           addToBody();
@@ -565,10 +519,10 @@ export function SearchSourceProvider(Promise, Private, config) {
        * Add the key and val to the body of the request
        */
       function addToBody() {
-        state.body = state.body || {};
+        data.body = data.body || {};
         // ignore if we already have a value
-        if (state.body[key] == null) {
-          state.body[key] = val;
+        if (data.body[key] == null) {
+          data.body[key] = val;
         }
       }
     }
@@ -577,15 +531,13 @@ export function SearchSourceProvider(Promise, Private, config) {
      * Walk the inheritance chain of a source and return it's
      * flat representation (taking into account merging rules)
      * @returns {Promise}
-     * @resolved {Object|null} - the flat state of the SearchSource
+     * @resolved {Object|null} - the flat data of the SearchSource
      */
     _flatten() {
-      const type = this._getType();
+      // the merged data of this dataSource and it's ancestors
+      const flatData = {};
 
-      // the merged state of this dataSource and it's ancestors
-      const flatState = {};
-
-      // function used to write each property from each state object in the chain to flat state
+      // function used to write each property from each data object in the chain to flat data
       const root = this;
 
       // start the chain at this source
@@ -593,17 +545,17 @@ export function SearchSourceProvider(Promise, Private, config) {
 
       // call the ittr and return it's promise
       return (function ittr() {
-        // iterate the _state object (not array) and
+        // iterate the _fields object (not array) and
         // pass each key:value pair to source._mergeProp. if _mergeProp
         // returns a promise, then wait for it to complete and call _mergeProp again
-        return Promise.all(_.map(current._state, function ittr(value, key) {
+        return Promise.all(_.map(current._fields, function ittr(value, key) {
           if (Promise.is(value)) {
             return value.then(function (value) {
               return ittr(value, key);
             });
           }
 
-          const prom = root._mergeProp(flatState, value, key);
+          const prom = root._mergeProp(flatData, value, key);
           return Promise.is(prom) ? prom : null;
         }))
           .then(function () {
@@ -617,82 +569,80 @@ export function SearchSourceProvider(Promise, Private, config) {
           });
       }())
         .then(function () {
-          if (type === 'search') {
-            // This is down here to prevent the circular dependency
-            flatState.body = flatState.body || {};
-
-            const computedFields = flatState.index.getComputedFields();
-            flatState.body.stored_fields = computedFields.storedFields;
-            flatState.body.script_fields = flatState.body.script_fields || {};
-            flatState.body.docvalue_fields = flatState.body.docvalue_fields || [];
-
-            _.extend(flatState.body.script_fields, computedFields.scriptFields);
-            flatState.body.docvalue_fields = _.union(flatState.body.docvalue_fields, computedFields.docvalueFields);
-
-            if (flatState.body._source) {
-              // exclude source fields for this index pattern specified by the user
-              const filter = fieldWildcardFilter(flatState.body._source.excludes);
-              flatState.body.docvalue_fields = flatState.body.docvalue_fields.filter(filter);
-            }
+          // This is down here to prevent the circular dependency
+          flatData.body = flatData.body || {};
 
-            // if we only want to search for certain fields
-            const fields = flatState.fields;
-            if (fields) {
-              // filter out the docvalue_fields, and script_fields to only include those that we are concerned with
-              flatState.body.docvalue_fields = _.intersection(flatState.body.docvalue_fields, fields);
-              flatState.body.script_fields = _.pick(flatState.body.script_fields, fields);
-
-              // request the remaining fields from both stored_fields and _source
-              const remainingFields = _.difference(fields, _.keys(flatState.body.script_fields));
-              flatState.body.stored_fields = remainingFields;
-              _.set(flatState.body, '_source.includes', remainingFields);
-            }
+          const computedFields = flatData.index.getComputedFields();
+          flatData.body.stored_fields = computedFields.storedFields;
+          flatData.body.script_fields = flatData.body.script_fields || {};
+          flatData.body.docvalue_fields = flatData.body.docvalue_fields || [];
 
-            flatState.body.query = buildESQuery(flatState.index, flatState.query, flatState.filters);
+          _.extend(flatData.body.script_fields, computedFields.scriptFields);
+          flatData.body.docvalue_fields = _.union(flatData.body.docvalue_fields, computedFields.docvalueFields);
 
-            if (flatState.highlightAll != null) {
-              if (flatState.highlightAll && flatState.body.query) {
-                flatState.body.highlight = getHighlightRequest(flatState.body.query, getConfig);
-              }
-              delete flatState.highlightAll;
+          if (flatData.body._source) {
+            // exclude source fields for this index pattern specified by the user
+            const filter = fieldWildcardFilter(flatData.body._source.excludes);
+            flatData.body.docvalue_fields = flatData.body.docvalue_fields.filter(filter);
+          }
+
+          // if we only want to search for certain fields
+          const fields = flatData.fields;
+          if (fields) {
+            // filter out the docvalue_fields, and script_fields to only include those that we are concerned with
+            flatData.body.docvalue_fields = _.intersection(flatData.body.docvalue_fields, fields);
+            flatData.body.script_fields = _.pick(flatData.body.script_fields, fields);
+
+            // request the remaining fields from both stored_fields and _source
+            const remainingFields = _.difference(fields, _.keys(flatData.body.script_fields));
+            flatData.body.stored_fields = remainingFields;
+            _.set(flatData.body, '_source.includes', remainingFields);
+          }
+
+          flatData.body.query = buildESQuery(flatData.index, flatData.query, flatData.filters);
+
+          if (flatData.highlightAll != null) {
+            if (flatData.highlightAll && flatData.body.query) {
+              flatData.body.highlight = getHighlightRequest(flatData.body.query, getConfig);
             }
+            delete flatData.highlightAll;
+          }
 
-            /**
-             * Translate a filter into a query to support es 3+
-             * @param  {Object} filter - The filter to translate
-             * @return {Object} the query version of that filter
-             */
-            const translateToQuery = function (filter) {
-              if (!filter) return;
+          /**
+           * Translate a filter into a query to support es 3+
+           * @param  {Object} filter - The filter to translate
+           * @return {Object} the query version of that filter
+           */
+          const translateToQuery = function (filter) {
+            if (!filter) return;
 
-              if (filter.query) {
-                return filter.query;
-              }
+            if (filter.query) {
+              return filter.query;
+            }
 
-              return filter;
-            };
+            return filter;
+          };
 
-            // re-write filters within filter aggregations
-            (function recurse(aggBranch) {
-              if (!aggBranch) return;
-              Object.keys(aggBranch).forEach(function (id) {
-                const agg = aggBranch[id];
+          // re-write filters within filter aggregations
+          (function recurse(aggBranch) {
+            if (!aggBranch) return;
+            Object.keys(aggBranch).forEach(function (id) {
+              const agg = aggBranch[id];
 
-                if (agg.filters) {
-                  // translate filters aggregations
-                  const filters = agg.filters.filters;
+              if (agg.filters) {
+                // translate filters aggregations
+                const filters = agg.filters.filters;
 
-                  Object.keys(filters).forEach(function (filterId) {
-                    filters[filterId] = translateToQuery(filters[filterId]);
-                  });
-                }
+                Object.keys(filters).forEach(function (filterId) {
+                  filters[filterId] = translateToQuery(filters[filterId]);
+                });
+              }
 
-                recurse(agg.aggs || agg.aggregations);
-              });
-            }(flatState.body.aggs || flatState.body.aggregations));
-          }
+              recurse(agg.aggs || agg.aggregations);
+            });
+          }(flatData.body.aggs || flatData.body.aggregations));
 
-          return flatState;
+          return flatData;
         });
     }
   }
diff --git a/src/ui/public/courier/utils/courier_inspector_utils.js b/src/ui/public/courier/utils/courier_inspector_utils.js
index 10f5f490f68fe..30b845e27bc56 100644
--- a/src/ui/public/courier/utils/courier_inspector_utils.js
+++ b/src/ui/public/courier/utils/courier_inspector_utils.js
@@ -25,7 +25,7 @@
  */
 function getRequestInspectorStats(searchSource) {
   const stats = {};
-  const index = searchSource.get('index');
+  const index = searchSource.getField('index');
 
   if (index) {
     stats['Index pattern'] = {
diff --git a/src/ui/public/doc_table/__tests__/doc_table.js b/src/ui/public/doc_table/__tests__/doc_table.js
index 7a00effd88f68..5395ddb4f216f 100644
--- a/src/ui/public/doc_table/__tests__/doc_table.js
+++ b/src/ui/public/doc_table/__tests__/doc_table.js
@@ -72,7 +72,7 @@ describe('docTable', function () {
       searchSource = Private(FixturesStubbedSearchSourceProvider);
     });
     init($elem, {
-      searchSource: searchSource,
+      searchSource,
       columns: [],
       sorting: ['@timestamp', 'desc']
     });
@@ -89,12 +89,12 @@ describe('docTable', function () {
   });
 
   it('should set the indexPattern to that of the searchSource', function () {
-    expect($scope.indexPattern).to.be(searchSource.get('index'));
+    expect($scope.indexPattern).to.be(searchSource.getField('index'));
   });
 
   it('should set size and sort on the searchSource', function () {
-    expect($scope.searchSource.sort.called).to.be(true);
-    expect($scope.searchSource.size.called).to.be(true);
+    expect($scope.searchSource.setField.getCall(0).args[0]).to.be('size');
+    expect($scope.searchSource.setField.getCall(1).args[0]).to.be('sort');
   });
 
   it('should have an addRows function that increases the row count', function () {
diff --git a/src/ui/public/doc_table/doc_table.js b/src/ui/public/doc_table/doc_table.js
index c8d1efea19457..b7e47a9c9d625 100644
--- a/src/ui/public/doc_table/doc_table.js
+++ b/src/ui/public/doc_table/doc_table.js
@@ -94,16 +94,16 @@ uiModules.get('kibana')
         $scope.$watch('searchSource', function () {
           if (!$scope.searchSource) return;
 
-          $scope.indexPattern = $scope.searchSource.get('index');
+          $scope.indexPattern = $scope.searchSource.getField('index');
 
-          $scope.searchSource.size(config.get('discover:sampleSize'));
-          $scope.searchSource.sort(getSort($scope.sorting, $scope.indexPattern));
+          $scope.searchSource.setField('size', config.get('discover:sampleSize'));
+          $scope.searchSource.setField('sort', getSort($scope.sorting, $scope.indexPattern));
 
           // Set the watcher after initialization
           $scope.$watchCollection('sorting', function (newSort, oldSort) {
           // Don't react if sort values didn't really change
             if (newSort === oldSort) return;
-            $scope.searchSource.sort(getSort(newSort, $scope.indexPattern));
+            $scope.searchSource.setField('sort', getSort(newSort, $scope.indexPattern));
             $scope.searchSource.fetchQueued();
           });
 
diff --git a/src/ui/public/vis/request_handlers/courier.js b/src/ui/public/vis/request_handlers/courier.js
index 812c3e9d3f8a5..c9750f936e9b4 100644
--- a/src/ui/public/vis/request_handlers/courier.js
+++ b/src/ui/public/vis/request_handlers/courier.js
@@ -82,8 +82,8 @@ const CourierRequestHandlerProvider = function () {
       // Using callParentStartHandlers: true we make sure, that the parent searchSource
       // onSearchRequestStart will be called properly even though we use an inherited
       // search source.
-      const timeFilterSearchSource = searchSource.makeChild({ callParentStartHandlers: true });
-      const requestSearchSource = timeFilterSearchSource.makeChild({ callParentStartHandlers: true });
+      const timeFilterSearchSource = searchSource.createChild({ callParentStartHandlers: true });
+      const requestSearchSource = timeFilterSearchSource.createChild({ callParentStartHandlers: true });
 
       // For now we need to mirror the history of the passed search source, since
       // the spy panel wouldn't work otherwise.
@@ -96,7 +96,7 @@ const CourierRequestHandlerProvider = function () {
         }
       });
 
-      requestSearchSource.aggs(function () {
+      requestSearchSource.setField('aggs', function () {
         return aggs.toDsl();
       });
 
@@ -104,12 +104,12 @@ const CourierRequestHandlerProvider = function () {
         return aggs.onSearchRequestStart(searchSource, searchRequest);
       });
 
-      timeFilterSearchSource.set('filter', () => {
-        return getTime(searchSource.get('index'), timeRange);
+      timeFilterSearchSource.setField('filter', () => {
+        return getTime(searchSource.getField('index'), timeRange);
       });
 
-      requestSearchSource.set('filter', filters);
-      requestSearchSource.set('query', query);
+      requestSearchSource.setField('filter', filters);
+      requestSearchSource.setField('query', query);
 
       const shouldQuery = (requestBodyHash) => {
         if (!searchSource.lastQuery || forceFetch) return true;
diff --git a/src/ui/public/visualize/__tests__/visualize.js b/src/ui/public/visualize/__tests__/visualize.js
index e98cb6598559d..cea05d50b9f17 100644
--- a/src/ui/public/visualize/__tests__/visualize.js
+++ b/src/ui/public/visualize/__tests__/visualize.js
@@ -64,8 +64,8 @@ describe('visualize directive', function () {
     $rootScope.uiState = uiState;
     $rootScope.searchSource = searchSource;
     $rootScope.savedObject = {
-      vis: vis,
-      searchSource: searchSource
+      vis,
+      searchSource,
     };
     $rootScope.updateState = updateState;
 
diff --git a/src/ui/public/visualize/loader/__tests__/visualize_loader.js b/src/ui/public/visualize/loader/__tests__/visualize_loader.js
index fbe6f1e37120b..2b5c4b7043e0a 100644
--- a/src/ui/public/visualize/loader/__tests__/visualize_loader.js
+++ b/src/ui/public/visualize/loader/__tests__/visualize_loader.js
@@ -42,8 +42,8 @@ describe('visualize loader', () => {
 
   function createSavedObject() {
     return {
-      vis: vis,
-      searchSource: searchSource
+      vis,
+      searchSource,
     };
   }
 
diff --git a/x-pack/plugins/ml/public/jobs/components/custom_url_editor/custom_url_editor_directive.js b/x-pack/plugins/ml/public/jobs/components/custom_url_editor/custom_url_editor_directive.js
index 8fdd222cf7d50..4cfeb6d9c0a8f 100644
--- a/x-pack/plugins/ml/public/jobs/components/custom_url_editor/custom_url_editor_directive.js
+++ b/x-pack/plugins/ml/public/jobs/components/custom_url_editor/custom_url_editor_directive.js
@@ -185,9 +185,9 @@ module.directive('mlCustomUrlEditor', function (Private) {
 
             const searchSourceJSON = response.get('kibanaSavedObjectMeta.searchSourceJSON');
             if (searchSourceJSON !== undefined) {
-              const searchSource = JSON.parse(searchSourceJSON);
-              filters = _.get(searchSource, 'filter', []);
-              query = searchSource.query;
+              const searchSourceData = JSON.parse(searchSourceJSON);
+              filters = _.get(searchSourceData, 'filter', []);
+              query = searchSourceData.query;
             }
 
             // Add time settings to the global state URL parameter with $earliest$ and
diff --git a/x-pack/plugins/ml/public/jobs/new_job/utils/new_job_utils.js b/x-pack/plugins/ml/public/jobs/new_job/utils/new_job_utils.js
index ac5cd7789de51..23e069ea22e4c 100644
--- a/x-pack/plugins/ml/public/jobs/new_job/utils/new_job_utils.js
+++ b/x-pack/plugins/ml/public/jobs/new_job/utils/new_job_utils.js
@@ -56,12 +56,12 @@ export function createSearchItems($route) {
 
   if (indexPattern.id === undefined &&
     savedSearch.id !== undefined) {
-    indexPattern = searchSource.get('index');
+    indexPattern = searchSource.getField('index');
 
     // Extract the query from the searchSource
     // Might be as a String in q.query, or
     // nested inside q.query.query_string
-    const q = searchSource.get('query');
+    const q = searchSource.getField('query');
     if (q !== undefined && q.language === 'lucene' && q.query !== undefined) {
       if (typeof q.query === 'string' && q.query !== '') {
         query.query_string.query = q.query;
@@ -71,7 +71,7 @@ export function createSearchItems($route) {
       }
     }
 
-    const fs = searchSource.get('filter');
+    const fs = searchSource.getField('filter');
     if (fs.length) {
       filters = fs;
     }