Support flattened label field with downsampling. (#118816) (#118935)

If flattened field is configured as non-dimension and non-metric field, then downsampling fails to execute successfully. Downsampling doesn't know how to use the flattened field or how to serialize it. This change addresses this.

Closes #116319

docs/changelog/118816.yaml

@@ -0,0 +1,6 @@
+pr: 118816
+summary: Support flattened field with downsampling
+area: Downsampling
+type: bug
+issues:
+ - 116319

server/src/main/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapper.java

@@ -52,6 +52,7 @@
 import org.elasticsearch.index.mapper.DocumentParserContext;
 import org.elasticsearch.index.mapper.DynamicFieldType;
 import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.KeywordFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.mapper.MapperBuilderContext;
@@ -666,7 +667,7 @@ public static final class RootFlattenedFieldType extends StringFieldType impleme
         private final boolean isDimension;
         private final int ignoreAbove;
 
-        public RootFlattenedFieldType(
+        RootFlattenedFieldType(
             String name,
             boolean indexed,
             boolean hasDocValues,
@@ -678,7 +679,7 @@ public RootFlattenedFieldType(
             this(name, indexed, hasDocValues, meta, splitQueriesOnWhitespace, eagerGlobalOrdinals, Collections.emptyList(), ignoreAbove);
         }
 
-        public RootFlattenedFieldType(
+        RootFlattenedFieldType(
             String name,
             boolean indexed,
             boolean hasDocValues,
@@ -802,6 +803,10 @@ public MappedFieldType getChildFieldType(String childPath) {
             return new KeyedFlattenedFieldType(name(), childPath, this);
         }
 
+        public MappedFieldType getKeyedFieldType() {
+            return new KeywordFieldMapper.KeywordFieldType(name() + KEYED_FIELD_SUFFIX);
+        }
+
         @Override
         public boolean isDimension() {
             return isDimension;

server/src/main/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldSyntheticWriterHelper.java

@@ -55,7 +55,7 @@
  * }`
  *
  */
-class FlattenedFieldSyntheticWriterHelper {
+public class FlattenedFieldSyntheticWriterHelper {
 
     private record Prefix(List<String> prefix) {
 
@@ -225,17 +225,17 @@ public boolean equals(Object obj) {
         }
     }
 
-    interface SortedKeyedValues {
+    public interface SortedKeyedValues {
         BytesRef next() throws IOException;
     }
 
     private final SortedKeyedValues sortedKeyedValues;
 
-    FlattenedFieldSyntheticWriterHelper(final SortedKeyedValues sortedKeyedValues) {
+    public FlattenedFieldSyntheticWriterHelper(final SortedKeyedValues sortedKeyedValues) {
         this.sortedKeyedValues = sortedKeyedValues;
     }
 
-    void write(final XContentBuilder b) throws IOException {
+    public void write(final XContentBuilder b) throws IOException {
         KeyValue curr = new KeyValue(sortedKeyedValues.next());
         KeyValue prev = KeyValue.EMPTY;
         final List<String> values = new ArrayList<>();

x-pack/plugin/downsample/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/downsample/70_flattened_field_type.yml

@@ -0,0 +1,307 @@
+---
+"A flattened label field":
+  - do:
+      indices.create:
+        index: source_index
+        body:
+          settings:
+            number_of_shards: 1
+            index:
+              mode: time_series
+              routing_path: [ metricset, k8s.pod.uid ]
+              time_series:
+                start_time: 2021-04-28T00:00:00Z
+                end_time: 2021-04-29T00:00:00Z
+          mappings:
+            subobjects: false
+            properties:
+              "@timestamp":
+                type: date
+              metricset:
+                type: keyword
+                time_series_dimension: true
+              k8s:
+                properties:
+                  pod:
+                    properties:
+                      uid:
+                        type: keyword
+                        time_series_dimension: true
+                      name:
+                        type: keyword
+                  agent:
+                    type: flattened
+                  value:
+                    type: long
+                    time_series_metric: gauge
+
+  - do:
+      bulk:
+        refresh: true
+        index: source_index
+        body:
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.4" }, "value": 10 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:24.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.5" }, "value": 20 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:50:44.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.6" }, "value": 12 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:51:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.7" }, "value": 15 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.7" }, "value": 9 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:23.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.8" }, "value": 16 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:50:53.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.9" }, "value": 25 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:51:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.10" }, "value": 17 }}'
+
+  - do:
+      indices.put_settings:
+        index: source_index
+        body:
+          index.blocks.write: true
+
+  - do:
+      indices.downsample:
+        index: source_index
+        target_index: target_index
+        body: >
+          {
+            "fixed_interval": "1h"
+          }
+  - is_true: acknowledged
+
+  - do:
+      search:
+        index: target_index
+        body:
+          sort: [ "_tsid", "@timestamp" ]
+
+  - length: { hits.hits: 4 }
+  - match: { hits.hits.0._source._doc_count: 2 }
+  - match: { hits.hits.0._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.0._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - match: { hits.hits.0._source.k8s\.agent: { "id": "second", "version": "2.1.8" } }
+
+  - match: { hits.hits.1._source._doc_count: 2 }
+  - match: { hits.hits.1._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.1._source.@timestamp: 2021-04-28T19:00:00.000Z }
+  - match: { hits.hits.1._source.k8s\.agent: { "id": "second", "version": "2.1.10" } }
+
+  - match: { hits.hits.2._source._doc_count: 2 }
+  - match: { hits.hits.2._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.2._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - match: { hits.hits.2._source.k8s\.agent: { "id": "first", "version": "2.0.5" } }
+
+  - match: { hits.hits.3._source._doc_count: 2 }
+  - match: { hits.hits.3._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.3._source.@timestamp: 2021-04-28T20:00:00.000Z }
+  - match: { hits.hits.3._source.k8s\.agent: { "id": "first", "version": "2.0.7" } }
+
+---
+"A flattened label field with no doc values":
+  - do:
+      indices.create:
+        index: source_index
+        body:
+          settings:
+            number_of_shards: 1
+            index:
+              mode: time_series
+              routing_path: [ metricset, k8s.pod.uid ]
+              time_series:
+                start_time: 2021-04-28T00:00:00Z
+                end_time: 2021-04-29T00:00:00Z
+          mappings:
+            subobjects: false
+            properties:
+              "@timestamp":
+                type: date
+              metricset:
+                type: keyword
+                time_series_dimension: true
+              k8s:
+                properties:
+                  pod:
+                    properties:
+                      uid:
+                        type: keyword
+                        time_series_dimension: true
+                      name:
+                        type: keyword
+                  agent:
+                    type: flattened
+                    doc_values: false
+                  value:
+                    type: long
+                    time_series_metric: gauge
+
+  - do:
+      bulk:
+        refresh: true
+        index: source_index
+        body:
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.4" }, "value": 10 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:24.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.5" }, "value": 20 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:50:44.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.6" }, "value": 12 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:51:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.7" }, "value": 15 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.7" }, "value": 9 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:23.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.8" }, "value": 16 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:50:53.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.9" }, "value": 25 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:51:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.10" }, "value": 17 }}'
+
+  - do:
+      indices.put_settings:
+        index: source_index
+        body:
+          index.blocks.write: true
+
+  - do:
+      indices.downsample:
+        index: source_index
+        target_index: target_index
+        body: >
+          {
+            "fixed_interval": "1h"
+          }
+  - is_true: acknowledged
+
+  - do:
+      search:
+        index: target_index
+        body:
+          sort: [ "_tsid", "@timestamp" ]
+
+  - length: { hits.hits: 4 }
+  - match: { hits.hits.0._source._doc_count: 2 }
+  - match: { hits.hits.0._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.0._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - is_false: hits.hits.0._source.k8s\.agent
+
+  - match: { hits.hits.1._source._doc_count: 2 }
+  - match: { hits.hits.1._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.1._source.@timestamp: 2021-04-28T19:00:00.000Z }
+  - is_false: hits.hits.1._source.k8s\.agent
+
+  - match: { hits.hits.2._source._doc_count: 2 }
+  - match: { hits.hits.2._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.2._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - is_false: hits.hits.2._source.k8s\.agent
+
+  - match: { hits.hits.3._source._doc_count: 2 }
+  - match: { hits.hits.3._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.3._source.@timestamp: 2021-04-28T20:00:00.000Z }
+  - is_false: hits.hits.3._source.k8s\.agent
+
+---
+"A flattened label field with mixed content":
+  - do:
+      indices.create:
+        index: source_index
+        body:
+          settings:
+            number_of_shards: 1
+            index:
+              mode: time_series
+              routing_path: [ metricset, k8s.pod.uid ]
+              time_series:
+                start_time: 2021-04-28T00:00:00Z
+                end_time: 2021-04-29T00:00:00Z
+          mappings:
+            subobjects: false
+            properties:
+              "@timestamp":
+                type: date
+              metricset:
+                type: keyword
+                time_series_dimension: true
+              k8s:
+                properties:
+                  pod:
+                    properties:
+                      uid:
+                        type: keyword
+                        time_series_dimension: true
+                      name:
+                        type: keyword
+                  agent:
+                    type: flattened
+                    null_value: my_null_value
+                  value:
+                    type: long
+                    time_series_metric: gauge
+
+  - do:
+      bulk:
+        refresh: true
+        index: source_index
+        body:
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.4", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11 }, "value": 10 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:24.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.5", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 20 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:50:44.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.6", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 12 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T20:51:04.467Z", "metricset": "pod", "k8s": {"pod": {"name": "cat", "uid":"947e4ced-1786-4e53-9e0c-5c447e959507"}, "agent": { "id": "first", "version": "2.0.7", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 15 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.7", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 9 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:50:23.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.8", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 16 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:50:53.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.9", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 25 }}'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T19:51:03.142Z", "metricset": "pod", "k8s": {"pod": {"name": "dog", "uid":"df3145b3-0563-4d3b-a0f7-897eb2876ea9"}, "agent": { "id": "second", "version": "2.1.10", "versions": ["1", "2", "3"], "optional_version": null, "dotted.version": "1.1", "numeric_version": 11}, "value": 17 }}'
+
+  - do:
+      indices.put_settings:
+        index: source_index
+        body:
+          index.blocks.write: true
+
+  - do:
+      indices.downsample:
+        index: source_index
+        target_index: target_index
+        body: >
+          {
+            "fixed_interval": "1h"
+          }
+  - is_true: acknowledged
+
+  - do:
+      search:
+        index: target_index
+        body:
+          sort: [ "_tsid", "@timestamp" ]
+
+  - length: { hits.hits: 4 }
+  - match: { hits.hits.0._source._doc_count: 2 }
+  - match: { hits.hits.0._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.0._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - match: { hits.hits.0._source.k8s\.agent: { "id": "second", "version": "2.1.8", "versions": ["1", "2", "3"], "dotted": {"version": "1.1"}, "numeric_version": "11", optional_version: "my_null_value" } }
+
+  - match: { hits.hits.1._source._doc_count: 2 }
+  - match: { hits.hits.1._source.k8s\.pod\.uid: df3145b3-0563-4d3b-a0f7-897eb2876ea9 }
+  - match: { hits.hits.1._source.@timestamp: 2021-04-28T19:00:00.000Z }
+  - match: { hits.hits.1._source.k8s\.agent: { "id": "second", "version": "2.1.10", "versions": ["1", "2", "3"], "dotted": {"version": "1.1"}, "numeric_version": "11", optional_version: "my_null_value" } }
+
+  - match: { hits.hits.2._source._doc_count: 2 }
+  - match: { hits.hits.2._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.2._source.@timestamp: 2021-04-28T18:00:00.000Z }
+  - match: { hits.hits.2._source.k8s\.agent: { "id": "first", "version": "2.0.5", "versions": ["1", "2", "3"], "dotted": {"version": "1.1"}, "numeric_version": "11", optional_version: "my_null_value" } }
+
+  - match: { hits.hits.3._source._doc_count: 2 }
+  - match: { hits.hits.3._source.k8s\.pod\.uid: 947e4ced-1786-4e53-9e0c-5c447e959507 }
+  - match: { hits.hits.3._source.@timestamp: 2021-04-28T20:00:00.000Z }
+  - match: { hits.hits.3._source.k8s\.agent: { "id": "first", "version": "2.0.7", "versions": ["1", "2", "3"], "dotted": {"version": "1.1"}, "numeric_version": "11", optional_version: "my_null_value" } }