Allow users compute statistics over retrieved batch datasets

core/src/main/java/feast/core/service/StatsService.java

@@ -31,7 +31,7 @@
 import feast.proto.core.CoreServiceProto.GetFeatureStatisticsResponse;
 import feast.proto.core.StoreProto;
 import feast.proto.core.StoreProto.Store.StoreType;
-import feast.storage.api.statistics.FeatureSetStatistics;
+import feast.storage.api.statistics.FeatureStatistics;
 import feast.storage.api.statistics.StatisticsRetriever;
 import feast.storage.connectors.bigquery.statistics.BigQueryStatisticsRetriever;
 import java.io.IOException;
@@ -200,7 +200,7 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDataset(
     // Else, add to the list of features we still need to retrieve statistics for.
     for (String featureName : features) {
       Feature feature = featureNameToFeature.get(featureName);
-      Optional<FeatureStatistics> cachedFeatureStatistics = Optional.empty();
+      Optional<feast.core.model.FeatureStatistics> cachedFeatureStatistics = Optional.empty();
       if (!forceRefresh) {
         cachedFeatureStatistics =
             featureStatisticsRepository.findFeatureStatisticsByFeatureAndDatasetId(
@@ -216,7 +216,7 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDataset(
     // Retrieve the balance of statistics after checking the cache, and add it to the
     // list of FeatureNameStatistics.
     if (featuresMissingStats.size() > 0) {
-      FeatureSetStatistics featureSetStatistics =
+      FeatureStatistics featureSetStatistics =
           statisticsRetriever.getFeatureStatistics(
               featureSet.toProto().getSpec(), featuresMissingStats, datasetId);
 
@@ -226,9 +226,9 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDataset(
           continue;
         }
         Feature feature = featureNameToFeature.get(stat.getName());
-        FeatureStatistics featureStatistics =
-            FeatureStatistics.createForDataset(feature, stat, datasetId);
-        Optional<FeatureStatistics> existingRecord =
+        feast.core.model.FeatureStatistics featureStatistics =
+            feast.core.model.FeatureStatistics.createForDataset(feature, stat, datasetId);
+        Optional<feast.core.model.FeatureStatistics> existingRecord =
             featureStatisticsRepository.findFeatureStatisticsByFeatureAndDatasetId(
                 featureStatistics.getFeature(), datasetId);
         existingRecord.ifPresent(statistics -> featureStatistics.setId(statistics.getId()));
@@ -270,7 +270,7 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDate(
     // Else, add to the list of features we still need to retrieve statistics for.
     for (String featureName : features) {
       Feature feature = featureNameToFeature.get(featureName);
-      Optional<FeatureStatistics> cachedFeatureStatistics = Optional.empty();
+      Optional<feast.core.model.FeatureStatistics> cachedFeatureStatistics = Optional.empty();
       if (!forceRefresh) {
         cachedFeatureStatistics =
             featureStatisticsRepository.findFeatureStatisticsByFeatureAndDate(feature, date);
@@ -285,7 +285,7 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDate(
     // Retrieve the balance of statistics after checking the cache, and add it to the
     // list of FeatureNameStatistics.
     if (featuresMissingStats.size() > 0) {
-      FeatureSetStatistics featureSetStatistics =
+      FeatureStatistics featureSetStatistics =
           statisticsRetriever.getFeatureStatistics(
               featureSet.toProto().getSpec(),
               featuresMissingStats,
@@ -297,8 +297,9 @@ private List<FeatureNameStatistics> getFeatureNameStatisticsByDate(
           continue;
         }
         Feature feature = featureNameToFeature.get(stat.getName());
-        FeatureStatistics featureStatistics = FeatureStatistics.createForDate(feature, stat, date);
-        Optional<FeatureStatistics> existingRecord =
+        feast.core.model.FeatureStatistics featureStatistics =
+            feast.core.model.FeatureStatistics.createForDate(feature, stat, date);
+        Optional<feast.core.model.FeatureStatistics> existingRecord =
             featureStatisticsRepository.findFeatureStatisticsByFeatureAndDate(
                 featureStatistics.getFeature(), date);
         existingRecord.ifPresent(statistics -> featureStatistics.setId(statistics.getId()));

docs/user-guide/feature-retrieval.md

@@ -107,6 +107,38 @@ Feast can retrieve features from any amount of feature sets, as long as they occ
 
 Point-in-time-correct joins also prevents the occurrence of feature leakage by trying to accurate the state of the world at a single point in time, instead of just joining features based on the nearest timestamps.
 
+### **Computing statistics over retrieved data**
+
+Feast is able to compute [TFDV](https://tensorflow.google.cn/tfx/tutorials/data_validation/tfdv_basic) compatible statistics over data retrieved from historical stores. The statistics can be used in conjunction with feature schemas and TFDV to verify the integrity of your retrieved dataset, or to [Facets](https://github.com/PAIR-code/facets) to visualize the distribution.
+
+The computation of statistics is not enabled by default. To indicate to Feast that the statistics are to be computed for a given historical retrieval request, pass `compute_statistics=True` to `get_batch_features`.
+
+```python
+dataset = client.get_batch_features(
+    feature_refs=features, 
+    entity_rows=entity_df 
+    compute_statistics=True
+)
+
+stats = dataset.statistics()
+```
+
+If a schema is already defined over the feature sets on question, tfdv can be used to detect anomalies over the dataset.
+
+```python
+# Build combined schema over retrieved dataset
+schema = schema_pb2.Schema()
+for feature_set in feature_sets:
+    fs_schema = feature_set.export_tfx_schema()
+    for feature_schema in fs_schema.feature:
+        if feature_schema.name in features:
+            schema.feature.append(feature_schema)
+
+# detect anomalies
+anomalies = tfdv.validate_statistics(statistics=stats, schema=schema)
+```
+
+
 ## Online feature retrieval
 
 Online feature retrieval works in much the same way as batch retrieval, with one important distinction: Online stores only maintain the current state of features. No historical data is served.

protos/feast/serving/ServingService.proto

@@ -20,6 +20,7 @@ package feast.serving;
 
 import "google/protobuf/timestamp.proto";
 import "feast/types/Value.proto";
+import "tensorflow_metadata/proto/v0/statistics.proto";
 
 option java_package = "feast.proto.serving";
 option java_outer_classname = "ServingAPIProto";
@@ -100,6 +101,18 @@ message GetOnlineFeaturesRequest {
     }
 }
 
+message GetBatchFeaturesRequest {
+    // List of features that are being retrieved
+    repeated FeatureReference features = 3;
+
+    // Source of the entity dataset containing the timestamps and entity keys to retrieve
+    // features for.
+    DatasetSource dataset_source = 2;
+
+    // Compute statistics for the dataset retrieved
+    bool compute_statistics = 4;
+}
+
 message GetOnlineFeaturesResponse {
     // Feature values retrieved from feast.
     repeated FieldValues field_values = 1;
@@ -134,15 +147,6 @@ message GetOnlineFeaturesResponse {
     }
 }
 
-message GetBatchFeaturesRequest {
-    // List of features that are being retrieved
-    repeated FeatureReference features = 3;
-
-    // Source of the entity dataset containing the timestamps and entity keys to retrieve
-    // features for.
-    DatasetSource dataset_source = 2;
-}
-
 message GetBatchFeaturesResponse {
     Job job = 1;
 }
@@ -196,6 +200,9 @@ message Job {
     // Output only. The data format for all the files.
     // For CSV format, the files contain both feature values and a column header.
     DataFormat data_format = 6;
+    // Output only. The statistics computed over
+    // the retrieved dataset. Only available for BigQuery stores.
+    tensorflow.metadata.v0.DatasetFeatureStatisticsList dataset_feature_statistics_list = 7;
 }
 
 message DatasetSource {

sdk/python/feast/client.py

@@ -51,10 +51,10 @@
     GetFeatureSetRequest,
     GetFeatureSetResponse,
     GetFeatureStatisticsRequest,
-    ListFeaturesRequest,
-    ListFeaturesResponse,
     ListFeatureSetsRequest,
     ListFeatureSetsResponse,
+    ListFeaturesRequest,
+    ListFeaturesResponse,
     ListIngestionJobsRequest,
     ListProjectsRequest,
     ListProjectsResponse,
@@ -561,6 +561,7 @@ def get_batch_features(
         self,
         feature_refs: List[str],
         entity_rows: Union[pd.DataFrame, str],
+        compute_statistics: bool = False,
         project: str = None,
     ) -> RetrievalJob:
         """
@@ -577,6 +578,8 @@ def get_batch_features(
                 Each entity in a feature set must be present as a column in this
                 dataframe. The datetime column must contain timestamps in
                 datetime64 format.
+            compute_statistics (bool):
+                Indicates whether Feast should compute statistics over the retrieved dataset.
             project: Specifies the project which contain the FeatureSets
                 which the requested features belong to.
 
@@ -656,6 +659,7 @@ def get_batch_features(
                     file_uris=staged_files, data_format=DataFormat.DATA_FORMAT_AVRO
                 )
             ),
+            compute_statistics=compute_statistics,
         )
 
         # Retrieve Feast Job object to manage life cycle of retrieval

sdk/python/feast/job.py

@@ -24,6 +24,7 @@
 from feast.serving.ServingService_pb2_grpc import ServingServiceStub
 from feast.source import Source
 from feast.wait import wait_retry_backoff
+from tensorflow_metadata.proto.v0 import statistics_pb2
 
 
 class RetrievalJob:
@@ -193,6 +194,26 @@ def to_chunked_dataframe(
     def __iter__(self):
         return iter(self.result())
 
+    def statistics(
+        self, timeout_sec: int = int(defaults[CONFIG_TIMEOUT_KEY])
+    ) -> statistics_pb2.DatasetFeatureStatisticsList:
+        """
+        Get statistics computed over the retrieved data set. Statistics will only be computed for
+        columns that are part of Feast, and not the columns that were provided.
+
+        Args:
+            timeout_sec (int):
+                Max no of seconds to wait until job is done. If "timeout_sec"
+                is exceeded, an exception will be raised.
+
+        Returns:
+            DatasetFeatureStatisticsList containing statistics of Feast features over the retrieved dataset.
+        """
+        self.get_avro_files(timeout_sec)  # wait for job completion
+        if self.job_proto.error:
+            raise Exception(self.job_proto.error)
+        return self.job_proto.dataset_feature_statistics_list
+
 
 class IngestJob:
     """

sdk/python/tests/test_client.py

@@ -34,8 +34,8 @@
 from feast.core.CoreService_pb2 import (
     GetFeastCoreVersionResponse,
     GetFeatureSetResponse,
-    ListFeaturesResponse,
     ListFeatureSetsResponse,
+    ListFeaturesResponse,
     ListIngestionJobsResponse,
 )
 from feast.core.FeatureSet_pb2 import EntitySpec as EntitySpecProto

serving/src/main/java/feast/serving/service/HistoricalServingService.java

@@ -81,7 +81,10 @@ public GetBatchFeaturesResponse getBatchFeatures(GetBatchFeaturesRequest getFeat
               public void run() {
                 HistoricalRetrievalResult result =
                     retriever.getHistoricalFeatures(
-                        retrievalId, getFeaturesRequest.getDatasetSource(), featureSetRequests);
+                        retrievalId,
+                        getFeaturesRequest.getDatasetSource(),
+                        featureSetRequests,
+                        getFeaturesRequest.getComputeStatistics());
                 jobService.upsert(resultToJob(result));
               }
             });
@@ -111,9 +114,11 @@ private Job resultToJob(HistoricalRetrievalResult result) {
     if (result.hasError()) {
       return builder.setError(result.getError()).build();
     }
-    return builder
-        .addAllFileUris(result.getFileUris())
-        .setDataFormat(result.getDataFormat())
-        .build();
+    Builder jobBuilder =
+        builder.addAllFileUris(result.getFileUris()).setDataFormat(result.getDataFormat());
+    if (result.getStats() != null) {
+      jobBuilder.setDatasetFeatureStatisticsList(result.getStats());
+    }
+    return builder.build();
   }
 }

storage/api/src/main/java/feast/storage/api/retriever/HistoricalRetrievalResult.java

@@ -22,6 +22,7 @@
 import java.io.Serializable;
 import java.util.List;
 import javax.annotation.Nullable;
+import org.tensorflow.metadata.v0.DatasetFeatureStatisticsList;
 
 /** Result of a historical feature retrieval request. */
 @AutoValue
@@ -40,6 +41,9 @@ public abstract class HistoricalRetrievalResult implements Serializable {
   @Nullable
   public abstract DataFormat getDataFormat();
 
+  @Nullable
+  public abstract DatasetFeatureStatisticsList getStats();
+
   /**
    * Instantiates a {@link HistoricalRetrievalResult} indicating that the retrieval was a failure,
    * together with its associated error.
@@ -75,10 +79,29 @@ public static HistoricalRetrievalResult success(
         .build();
   }
 
+  /**
+   * Adds statistics to the result
+   *
+   * @param stats {@link DatasetFeatureStatisticsList} for the retrieved dataset
+   * @return {@link HistoricalRetrievalResult}
+   */
+  public HistoricalRetrievalResult withStats(DatasetFeatureStatisticsList stats) {
+    return toBuilder().setStats(stats).build();
+  }
+
   static Builder newBuilder() {
     return new AutoValue_HistoricalRetrievalResult.Builder();
   }
 
+  Builder toBuilder() {
+    return newBuilder()
+        .setId(getId())
+        .setStatus(getStatus())
+        .setFileUris(getFileUris())
+        .setError(getError())
+        .setDataFormat(getDataFormat());
+  }
+
   @AutoValue.Builder
   abstract static class Builder {
     abstract Builder setId(String id);
@@ -91,6 +114,8 @@ abstract static class Builder {
 
     abstract Builder setDataFormat(DataFormat dataFormat);
 
+    abstract Builder setStats(DatasetFeatureStatisticsList stats);
+
     abstract HistoricalRetrievalResult build();
   }
 

storage/api/src/main/java/feast/storage/api/retriever/HistoricalRetriever.java

@@ -41,9 +41,13 @@ public interface HistoricalRetriever {
    *     entity columns.
    * @param featureSetRequests List of {@link FeatureSetRequest} to feature references in the
    *     request tied to that feature set.
+   * @param computeStatistics whether to compute statistics over the resultant dataset.
    * @return {@link HistoricalRetrievalResult} if successful, contains the location of the results,
    *     else contains the error to be returned to the user.
    */
   HistoricalRetrievalResult getHistoricalFeatures(
-      String retrievalId, DatasetSource datasetSource, List<FeatureSetRequest> featureSetRequests);
+      String retrievalId,
+      DatasetSource datasetSource,
+      List<FeatureSetRequest> featureSetRequests,
+      boolean computeStatistics);
 }

storage/api/src/main/java/feast/storage/api/statistics/FeatureSetStatistics.java → storage/api/src/main/java/feast/storage/api/statistics/FeatureStatistics.java

@@ -20,16 +20,16 @@
 import com.google.common.collect.ImmutableList;
 import org.tensorflow.metadata.v0.FeatureNameStatistics;
 
-/** Feature statistics for a feature set over a bounded set of data. */
+/** Feature statistics over a bounded set of data. */
 @AutoValue
-public abstract class FeatureSetStatistics {
+public abstract class FeatureStatistics {
 
   public abstract long getNumExamples();
 
   public abstract ImmutableList<FeatureNameStatistics> getFeatureNameStatistics();
 
   public static Builder newBuilder() {
-    return new AutoValue_FeatureSetStatistics.Builder();
+    return new AutoValue_FeatureStatistics.Builder();
   }
 
   @AutoValue.Builder
@@ -43,6 +43,6 @@ public Builder addFeatureNameStatistics(FeatureNameStatistics featureNameStatist
       return this;
     }
 
-    public abstract FeatureSetStatistics build();
+    public abstract FeatureStatistics build();
   }
 }