Intercept filters to knn queries (#138457)

`knn` queries can have filter queries. Those filters may contain
semantic queries (e.g. `knn`, `sparse_vector`, or `match` queries
targetting `semantic_text` fields). We also need to intercept those
in order to perform inference for their `query` field during the
coordinator node rewrite.

This commit achieves this with the following changes:

- `SemanticKnnVectorQueryRewriteInterceptor` attempts to rewrite filter queries.
This means we rely on a rewrite cycle to attempt to intercept every query down the
tree of each filter query.

- `InterceptedInferenceQueryBuilder` now has a `customCoordinatorNodeRewrite` method
that subclasses can implement to implement additional rewriting logic needed, e.g. rewrite
inner queries.

- `InterceptedInferenceKnnVectorQueryBuilder` implements `customCoordinatorNodeRewrite` so
that the filter queries are rewritten.

This commit fixes the exceptions throws in #138410. However, searches that contain semantic text
queries as filters to a semantic text knn query will return `0` hits due to another issue that
is captured in #138184.

Closes #138410

Author: dimitris-athanasiou

docs/changelog/138457.yaml

@@ -0,0 +1,6 @@
+pr: 138457
+summary: Intercept filters to knn queries
+area: Vector Search
+type: bug
+issues:
+ - 138410

server/src/main/java/org/elasticsearch/plugins/internal/rewriter/QueryRewriteInterceptor.java

@@ -12,6 +12,7 @@
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryRewriteContext;
 
+import java.io.IOException;
 import java.util.Map;
 
 /**
@@ -27,7 +28,7 @@ public interface QueryRewriteInterceptor {
      * @param queryBuilder the original {@link QueryBuilder} to potentially rewrite
      * @return the rewritten {@link QueryBuilder}, or the original instance if no rewrite was needed
      */
-    QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder);
+    QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) throws IOException;
 
     /**
      * Name of the query to be intercepted and rewritten.
@@ -52,7 +53,7 @@ public String getQueryName() {
         }
 
         @Override
-        public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) {
+        public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) throws IOException {
             QueryRewriteInterceptor interceptor = interceptors.get(queryBuilder.getName());
             if (interceptor != null) {
                 return interceptor.interceptAndRewrite(context, queryBuilder);

server/src/main/java/org/elasticsearch/search/vectors/KnnVectorQueryBuilder.java

@@ -357,6 +357,13 @@ public KnnVectorQueryBuilder addFilterQueries(List<QueryBuilder> filterQueries)
         return this;
     }
 
+    public KnnVectorQueryBuilder setFilterQueries(List<QueryBuilder> filterQueries) {
+        Objects.requireNonNull(filterQueries);
+        this.filterQueries.clear();
+        this.filterQueries.addAll(filterQueries);
+        return this;
+    }
+
     @Override
     protected void doWriteTo(StreamOutput out) throws IOException {
         if (queryVectorSupplier != null) {

server/src/test/java/org/elasticsearch/search/vectors/AbstractKnnVectorQueryBuilderTestCase.java

@@ -32,6 +32,7 @@
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.index.query.QueryRewriteContext;
 import org.elasticsearch.index.query.QueryShardException;
+import org.elasticsearch.index.query.RandomQueryBuilder;
 import org.elasticsearch.index.query.Rewriteable;
 import org.elasticsearch.index.query.SearchExecutionContext;
 import org.elasticsearch.index.query.TermQueryBuilder;
@@ -565,4 +566,11 @@ public void testRewriteWithQueryVectorBuilder() throws Exception {
         assertThat(rewritten.filterQueries(), hasSize(numFilters));
         assertThat(rewritten.filterQueries(), equalTo(filters));
     }
+
+    public void testSetFilterQueries() {
+        KnnVectorQueryBuilder knnQueryBuilder = doCreateTestQueryBuilder();
+        List<QueryBuilder> newFilters = randomList(5, () -> RandomQueryBuilder.createQuery(random()));
+        knnQueryBuilder.setFilterQueries(newFilters);
+        assertThat(knnQueryBuilder.filterQueries(), equalTo(newFilters));
+    }
 }

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/InferenceFeatures.java

@@ -13,6 +13,7 @@
 import org.elasticsearch.xpack.inference.mapper.SemanticInferenceMetadataFieldsMapper;
 import org.elasticsearch.xpack.inference.mapper.SemanticTextFieldMapper;
 import org.elasticsearch.xpack.inference.queries.InterceptedInferenceQueryBuilder;
+import org.elasticsearch.xpack.inference.queries.SemanticKnnVectorQueryRewriteInterceptor;
 import org.elasticsearch.xpack.inference.queries.SemanticQueryBuilder;
 import org.elasticsearch.xpack.inference.rank.textsimilarity.TextSimilarityRankRetrieverBuilder;
 
@@ -109,6 +110,7 @@ public Set<NodeFeature> getTestFeatures() {
                 SemanticQueryBuilder.SEMANTIC_QUERY_MULTIPLE_INFERENCE_IDS,
                 SemanticQueryBuilder.SEMANTIC_QUERY_FILTER_FIELD_CAPS_FIX,
                 InterceptedInferenceQueryBuilder.NEW_SEMANTIC_QUERY_INTERCEPTORS,
+                SemanticKnnVectorQueryRewriteInterceptor.SEMANTIC_KNN_VECTOR_QUERY_FILTERS_REWRITE_INTERCEPTION_SUPPORTED,
                 TEXT_SIMILARITY_RERANKER_SNIPPETS,
                 ModelStats.SEMANTIC_TEXT_USAGE,
                 SEARCH_USAGE_EXTENDED_DATA,

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/InterceptedInferenceKnnVectorQueryBuilder.java

@@ -32,7 +32,9 @@
 import org.elasticsearch.xpack.inference.mapper.SemanticTextFieldMapper;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 
 import static org.elasticsearch.transport.RemoteClusterAware.LOCAL_CLUSTER_GROUP_KEY;
@@ -91,6 +93,33 @@ protected FullyQualifiedInferenceId getInferenceIdOverride() {
         return modelId != null ? new FullyQualifiedInferenceId(LOCAL_CLUSTER_GROUP_KEY, modelId) : null;
     }
 
+    @Override
+    protected InterceptedInferenceQueryBuilder<KnnVectorQueryBuilder> customDoRewriteGetInferenceResults(
+        QueryRewriteContext queryRewriteContext
+    ) throws IOException {
+        // knn query may contain filters that are also intercepted.
+        // We need to rewrite those here so that we can get inference results for them too.
+        return rewriteFilterQueries(queryRewriteContext);
+    }
+
+    private InterceptedInferenceQueryBuilder<KnnVectorQueryBuilder> rewriteFilterQueries(QueryRewriteContext queryRewriteContext)
+        throws IOException {
+        boolean filtersChanged = false;
+        List<QueryBuilder> rewrittenFilters = new ArrayList<>(originalQuery.filterQueries().size());
+        for (QueryBuilder filter : originalQuery.filterQueries()) {
+            QueryBuilder rewrittenFilter = filter.rewrite(queryRewriteContext);
+            if (rewrittenFilter != filter) {
+                filtersChanged = true;
+            }
+            rewrittenFilters.add(rewrittenFilter);
+        }
+        if (filtersChanged) {
+            originalQuery.setFilterQueries(rewrittenFilters);
+            return copy(inferenceResultsMap, inferenceResultsMapSupplier, ccsRequest);
+        }
+        return this;
+    }
+
     @Override
     protected void coordinatorNodeValidate(ResolvedIndices resolvedIndices) {
         if (originalQuery.queryVector() == null && originalQuery.queryVectorBuilder() instanceof TextEmbeddingQueryVectorBuilder == false) {
@@ -119,7 +148,7 @@ protected void coordinatorNodeValidate(ResolvedIndices resolvedIndices) {
     }
 
     @Override
-    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
+    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) throws IOException {
         QueryBuilder rewritten = this;
         if (queryRewriteContext.getMinTransportVersion().supports(NEW_SEMANTIC_QUERY_INTERCEPTORS) == false) {
             rewritten = BWC_INTERCEPTOR.interceptAndRewrite(queryRewriteContext, originalQuery);
@@ -129,7 +158,7 @@ protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
     }
 
     @Override
-    protected QueryBuilder copy(
+    protected InterceptedInferenceQueryBuilder<KnnVectorQueryBuilder> copy(
         Map<FullyQualifiedInferenceId, InferenceResults> inferenceResultsMap,
         SetOnce<Map<FullyQualifiedInferenceId, InferenceResults>> inferenceResultsMapSupplier,
         boolean ccsRequest

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/InterceptedInferenceMatchQueryBuilder.java

@@ -65,7 +65,7 @@ protected String getQuery() {
     }
 
     @Override
-    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
+    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) throws IOException {
         QueryBuilder rewritten = this;
         if (queryRewriteContext.getMinTransportVersion().supports(NEW_SEMANTIC_QUERY_INTERCEPTORS) == false) {
             rewritten = BWC_INTERCEPTOR.interceptAndRewrite(queryRewriteContext, originalQuery);
@@ -75,7 +75,7 @@ protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
     }
 
     @Override
-    protected QueryBuilder copy(
+    protected InterceptedInferenceQueryBuilder<MatchQueryBuilder> copy(
         Map<FullyQualifiedInferenceId, InferenceResults> inferenceResultsMap,
         SetOnce<Map<FullyQualifiedInferenceId, InferenceResults>> inferenceResultsMapSupplier,
         boolean ccsRequest

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/InterceptedInferenceQueryBuilder.java

@@ -152,14 +152,14 @@ protected InterceptedInferenceQueryBuilder(
      * @param queryRewriteContext The query rewrite context
      * @return The query builder rewritten to a backwards-compatible form
      */
-    protected abstract QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext);
+    protected abstract QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) throws IOException;
 
     /**
      * Generate a copy of {@code this}.
      *
-     * @param inferenceResultsMap The inference results map
+     * @param inferenceResultsMap         The inference results map
      * @param inferenceResultsMapSupplier The inference results map supplier
-     * @param ccsRequest Flag indicating if this is a CCS request
+     * @param ccsRequest                  Flag indicating if this is a CCS request
      * @return A copy of {@code this} with the provided inference results map
      */
     protected abstract QueryBuilder copy(
@@ -209,6 +209,15 @@ protected FullyQualifiedInferenceId getInferenceIdOverride() {
      */
     protected void coordinatorNodeValidate(ResolvedIndices resolvedIndices) {}
 
+    /**
+     * A hook for subclasses to do additional rewriting and inference result fetching while we are on the coordinator node.
+     * An example usage is {@link InterceptedInferenceKnnVectorQueryBuilder} which needs to rewrite the knn queries filters.
+     */
+    protected InterceptedInferenceQueryBuilder<T> customDoRewriteGetInferenceResults(QueryRewriteContext queryRewriteContext)
+        throws IOException {
+        return this;
+    }
+
     @Override
     protected void doWriteTo(StreamOutput out) throws IOException {
         if (inferenceResultsMapSupplier != null) {
@@ -304,7 +313,7 @@ private QueryBuilder doRewriteBuildQuery(QueryRewriteContext indexMetadataContex
         return queryFields(inferenceFieldsToQuery, nonInferenceFieldsToQuery, indexMetadataContext);
     }
 
-    private QueryBuilder doRewriteGetInferenceResults(QueryRewriteContext queryRewriteContext) {
+    private QueryBuilder doRewriteGetInferenceResults(QueryRewriteContext queryRewriteContext) throws IOException {
         QueryBuilder rewrittenBwC = doRewriteBwC(queryRewriteContext);
         if (rewrittenBwC != this) {
             return rewrittenBwC;
@@ -344,6 +353,15 @@ private QueryBuilder doRewriteGetInferenceResults(QueryRewriteContext queryRewri
             );
         }
 
+        InterceptedInferenceQueryBuilder<T> rewritten = customDoRewriteGetInferenceResults(queryRewriteContext);
+        return rewritten.doRewriteWaitForInferenceResults(queryRewriteContext, inferenceIds, ccsRequest);
+    }
+
+    private QueryBuilder doRewriteWaitForInferenceResults(
+        QueryRewriteContext queryRewriteContext,
+        Set<FullyQualifiedInferenceId> inferenceIds,
+        boolean ccsRequest
+    ) {
         if (inferenceResultsMapSupplier != null) {
             // Additional inference results have already been requested, and we are waiting for them to continue the rewrite process
             return getNewInferenceResultsFromSupplier(inferenceResultsMapSupplier, this, m -> copy(m, null, ccsRequest));
@@ -376,7 +394,6 @@ private QueryBuilder doRewriteGetInferenceResults(QueryRewriteContext queryRewri
         } else {
             rewritten = copy(inferenceResultsMap, newInferenceResultsMapSupplier, ccsRequest);
         }
-
         return rewritten;
     }
 

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/InterceptedInferenceSparseVectorQueryBuilder.java

@@ -106,7 +106,7 @@ protected void coordinatorNodeValidate(ResolvedIndices resolvedIndices) {
     }
 
     @Override
-    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
+    protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) throws IOException {
         QueryBuilder rewritten = this;
         if (queryRewriteContext.getMinTransportVersion().supports(NEW_SEMANTIC_QUERY_INTERCEPTORS) == false) {
             rewritten = BWC_INTERCEPTOR.interceptAndRewrite(queryRewriteContext, originalQuery);
@@ -116,7 +116,7 @@ protected QueryBuilder doRewriteBwC(QueryRewriteContext queryRewriteContext) {
     }
 
     @Override
-    protected QueryBuilder copy(
+    protected InterceptedInferenceQueryBuilder<SparseVectorQueryBuilder> copy(
         Map<FullyQualifiedInferenceId, InferenceResults> inferenceResultsMap,
         SetOnce<Map<FullyQualifiedInferenceId, InferenceResults>> inferenceResultsMapSupplier,
         boolean ccsRequest

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/SemanticKnnVectorQueryRewriteInterceptor.java

@@ -7,21 +7,50 @@
 
 package org.elasticsearch.xpack.inference.queries;
 
+import org.elasticsearch.features.NodeFeature;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryRewriteContext;
 import org.elasticsearch.plugins.internal.rewriter.QueryRewriteInterceptor;
 import org.elasticsearch.search.vectors.KnnVectorQueryBuilder;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
 public class SemanticKnnVectorQueryRewriteInterceptor implements QueryRewriteInterceptor {
+
+    public static final NodeFeature SEMANTIC_KNN_VECTOR_QUERY_FILTERS_REWRITE_INTERCEPTION_SUPPORTED = new NodeFeature(
+        "search.semantic_knn_vector_query_filters_rewrite_interception_supported"
+    );
+
     @Override
-    public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) {
+    public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) throws IOException {
         if (queryBuilder instanceof KnnVectorQueryBuilder knnVectorQueryBuilder) {
-            return new InterceptedInferenceKnnVectorQueryBuilder(knnVectorQueryBuilder);
+            return interceptKnnQuery(context, knnVectorQueryBuilder);
         } else {
             throw new IllegalStateException("Unexpected query builder type: " + queryBuilder.getClass());
         }
     }
 
+    private static InterceptedInferenceKnnVectorQueryBuilder interceptKnnQuery(
+        QueryRewriteContext context,
+        KnnVectorQueryBuilder knnVectorQueryBuilder
+    ) throws IOException {
+        boolean changed = false;
+        List<QueryBuilder> rewrittenFilters = new ArrayList<>(knnVectorQueryBuilder.filterQueries().size());
+        for (QueryBuilder filter : knnVectorQueryBuilder.filterQueries()) {
+            QueryBuilder rewritten = filter.rewrite(context);
+            if (rewritten != filter) {
+                changed = true;
+            }
+            rewrittenFilters.add(rewritten);
+        }
+        if (changed) {
+            knnVectorQueryBuilder.setFilterQueries(rewrittenFilters);
+        }
+        return new InterceptedInferenceKnnVectorQueryBuilder(knnVectorQueryBuilder);
+    }
+
     @Override
     public String getQueryName() {
         return KnnVectorQueryBuilder.NAME;