Fix script score queries not getting cached

CHANGELOG.md

@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 * Fix use-after-free case on nmslib search path [#1305](https://github.com/opensearch-project/k-NN/pull/1305)
 * Allow nested knn field mapping when train model [#1318](https://github.com/opensearch-project/k-NN/pull/1318)
 * Properly designate model state for actively training models when nodes crash or leave cluster [#1317](https://github.com/opensearch-project/k-NN/pull/1317)
+* Fix script score queries not getting cached [#1367](https://github.com/opensearch-project/k-NN/pull/1367)
 ### Infrastructure
 * Upgrade gradle to 8.4 [1289](https://github.com/opensearch-project/k-NN/pull/1289)
 * Refactor security testing to install from individual components [#1307](https://github.com/opensearch-project/k-NN/pull/1307)

qa/restart-upgrade/src/test/java/org/opensearch/knn/bwc/ScriptScoringIT.java

@@ -15,6 +15,7 @@
 import org.opensearch.knn.index.SpaceType;
 import org.opensearch.core.rest.RestStatus;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -107,7 +108,7 @@ private void validateKNNInnerProductScriptScoreSearch(String testIndex, String t
         params.put(QUERY_VALUE, queryVector);
         params.put(METHOD_PARAMETER_SPACE_TYPE, SpaceType.INNER_PRODUCT.getValue());
 
-        Request request = constructKNNScriptQueryRequest(testIndex, qb, params, k);
+        Request request = constructKNNScriptQueryRequest(testIndex, qb, params, k, Collections.emptyMap());
         Response response = client().performRequest(request);
         assertEquals(request.getEndpoint() + ": failed", RestStatus.OK, RestStatus.fromCode(response.getStatusLine().getStatusCode()));
 

src/main/java/org/opensearch/knn/plugin/script/KNNScoreScriptFactory.java

@@ -6,64 +6,21 @@
 package org.opensearch.knn.plugin.script;
 
 import org.apache.lucene.search.IndexSearcher;
-import org.opensearch.knn.plugin.stats.KNNCounter;
-import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.script.ScoreScript;
+import org.opensearch.script.ScriptFactory;
 import org.opensearch.search.lookup.SearchLookup;
 
-import java.io.IOException;
 import java.util.Map;
 
-public class KNNScoreScriptFactory implements ScoreScript.LeafFactory {
-    private final Map<String, Object> params;
-    private final SearchLookup lookup;
-    private String similaritySpace;
-    private String field;
-    private Object query;
-    private KNNScoringSpace knnScoringSpace;
-
-    private IndexSearcher searcher;
-
-    public KNNScoreScriptFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher searcher) {
-        KNNCounter.SCRIPT_QUERY_REQUESTS.increment();
-        this.params = params;
-        this.lookup = lookup;
-        this.field = getValue(params, "field").toString();
-        this.similaritySpace = getValue(params, "space_type").toString();
-        this.query = getValue(params, "query_value");
-        this.searcher = searcher;
-
-        this.knnScoringSpace = KNNScoringSpaceFactory.create(
-            this.similaritySpace,
-            this.query,
-            lookup.doc().mapperService().fieldType(this.field)
-        );
-    }
-
-    private Object getValue(Map<String, Object> params, String fieldName) {
-        final Object value = params.get(fieldName);
-        if (value != null) return value;
-
-        KNNCounter.SCRIPT_QUERY_ERRORS.increment();
-        throw new IllegalArgumentException("Missing parameter [" + fieldName + "]");
-    }
-
+public class KNNScoreScriptFactory implements ScoreScript.Factory, ScriptFactory {
     @Override
-    public boolean needs_score() {
-        return false;
+    public boolean isResultDeterministic() {
+        // This implies the results are cacheable
+        return true;
     }
 
-    /**
-     * For each segment, supply the KNNScoreScript that should be used to re-score the documents returned from the
-     * query. Because the method to score the documents was set during factory construction, the scripts are agnostic of
-     * the similarity space. The KNNScoringSpace will return the correct script, given the query, the field type, and
-     * the similarity space.
-     *
-     * @param ctx LeafReaderContext for the segment
-     * @return ScoreScript to be executed
-     */
     @Override
-    public ScoreScript newInstance(LeafReaderContext ctx) throws IOException {
-        return knnScoringSpace.getScoreScript(params, field, lookup, ctx, this.searcher);
+    public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher) {
+        return new KNNScoreScriptLeafFactory(params, lookup, indexSearcher);
     }
 }

src/main/java/org/opensearch/knn/plugin/script/KNNScoreScriptLeafFactory.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.plugin.script;
+
+import java.io.IOException;
+import java.util.Locale;
+import java.util.Map;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.IndexSearcher;
+import org.opensearch.knn.plugin.stats.KNNCounter;
+import org.opensearch.script.ScoreScript;
+import org.opensearch.search.lookup.SearchLookup;
+
+/*
+ * A factory that creates KNNScoreScriptLeafFactory objects. The factory is responsible for parsing the parameters
+ * passed in the query and creating the KNNScoreScriptLeafFactory object.
+ */
+public class KNNScoreScriptLeafFactory implements ScoreScript.LeafFactory {
+    private final Map<String, Object> params;
+    private final SearchLookup lookup;
+    private final String similaritySpace;
+    private final String field;
+    private final Object query;
+    private final KNNScoringSpace knnScoringSpace;
+    private final IndexSearcher searcher;
+
+    public KNNScoreScriptLeafFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher searcher) {
+        KNNCounter.SCRIPT_QUERY_REQUESTS.increment();
+        this.params = params;
+        this.lookup = lookup;
+        this.field = getValue(params, "field").toString();
+        this.similaritySpace = getValue(params, "space_type").toString();
+        this.query = getValue(params, "query_value");
+        this.searcher = searcher;
+
+        this.knnScoringSpace = KNNScoringSpaceFactory.create(
+            this.similaritySpace,
+            this.query,
+            lookup.doc().mapperService().fieldType(this.field)
+        );
+    }
+
+    private Object getValue(Map<String, Object> params, String fieldName) {
+        final Object value = params.get(fieldName);
+        if (value != null) return value;
+
+        KNNCounter.SCRIPT_QUERY_ERRORS.increment();
+        throw new IllegalArgumentException(String.format(Locale.ROOT, "Missing parameter [%s]", fieldName));
+    }
+
+    @Override
+    public boolean needs_score() {
+        return false;
+    }
+
+    /**
+     * For each segment, supply the KNNScoreScript that should be used to re-score the documents returned from the
+     * query. Because the method to score the documents was set during factory construction, the scripts are agnostic of
+     * the similarity space. The KNNScoringSpace will return the correct script, given the query, the field type, and
+     * the similarity space.
+     *
+     * @param ctx LeafReaderContext for the segment
+     * @return ScoreScript to be executed
+     */
+    @Override
+    public ScoreScript newInstance(LeafReaderContext ctx) throws IOException {
+        return knnScoringSpace.getScoreScript(params, field, lookup, ctx, this.searcher);
+    }
+}

src/main/java/org/opensearch/knn/plugin/script/KNNScoringScriptEngine.java

@@ -39,7 +39,7 @@ public <FactoryType> FactoryType compile(String name, String code, ScriptContext
             KNNCounter.SCRIPT_COMPILATION_ERRORS.increment();
             throw new IllegalArgumentException("Unknown script name " + code);
         }
-        ScoreScript.Factory factory = KNNScoreScriptFactory::new;
+        ScoreScript.Factory factory = new KNNScoreScriptFactory();
         return context.factoryClazz.cast(factory);
     }
 

src/test/java/org/opensearch/knn/index/VectorDataTypeIT.java

@@ -350,7 +350,8 @@ public void testL2PainlessScriptingWithByteVectorDataType() throws Exception {
             Collections.emptyMap(),
             Script.DEFAULT_SCRIPT_LANG,
             source,
-            4
+            4,
+            Collections.emptyMap()
         );
 
         Response response = client().performRequest(request);
@@ -370,7 +371,8 @@ public void testL2PainlessScriptingWithFloatVectorDataType() throws Exception {
             Collections.emptyMap(),
             Script.DEFAULT_SCRIPT_LANG,
             source,
-            4
+            4,
+            Collections.emptyMap()
         );
 
         Response response = client().performRequest(request);

src/test/java/org/opensearch/knn/plugin/script/KNNScriptScoringIT.java

@@ -25,9 +25,11 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.containsString;
@@ -451,7 +453,7 @@ public void testHammingScriptScore_Long() throws Exception {
         params1.put("field", FIELD_NAME);
         params1.put("query_value", queryValue1);
         params1.put("space_type", SpaceType.HAMMING_BIT.getValue());
-        Request request1 = constructKNNScriptQueryRequest(INDEX_NAME, qb1, params1, 4);
+        Request request1 = constructKNNScriptQueryRequest(INDEX_NAME, qb1, params1, 4, Collections.emptyMap());
         Response response1 = client().performRequest(request1);
         assertEquals(request1.getEndpoint() + ": failed", RestStatus.OK, RestStatus.fromCode(response1.getStatusLine().getStatusCode()));
 
@@ -491,7 +493,7 @@ public void testHammingScriptScore_Long() throws Exception {
         params2.put("field", FIELD_NAME);
         params2.put("query_value", queryValue2);
         params2.put("space_type", SpaceType.HAMMING_BIT.getValue());
-        Request request2 = constructKNNScriptQueryRequest(INDEX_NAME, qb2, params2, 4);
+        Request request2 = constructKNNScriptQueryRequest(INDEX_NAME, qb2, params2, 4, Collections.emptyMap());
         Response response2 = client().performRequest(request2);
         assertEquals(request2.getEndpoint() + ": failed", RestStatus.OK, RestStatus.fromCode(response2.getStatusLine().getStatusCode()));
 
@@ -561,7 +563,7 @@ public void testHammingScriptScore_Base64() throws Exception {
         params1.put("field", FIELD_NAME);
         params1.put("query_value", queryValue1);
         params1.put("space_type", SpaceType.HAMMING_BIT.getValue());
-        Request request1 = constructKNNScriptQueryRequest(INDEX_NAME, qb1, params1, 4);
+        Request request1 = constructKNNScriptQueryRequest(INDEX_NAME, qb1, params1, 4, Collections.emptyMap());
         Response response1 = client().performRequest(request1);
         assertEquals(request1.getEndpoint() + ": failed", RestStatus.OK, RestStatus.fromCode(response1.getStatusLine().getStatusCode()));
 
@@ -601,7 +603,7 @@ public void testHammingScriptScore_Base64() throws Exception {
         params2.put("field", FIELD_NAME);
         params2.put("query_value", queryValue2);
         params2.put("space_type", SpaceType.HAMMING_BIT.getValue());
-        Request request2 = constructKNNScriptQueryRequest(INDEX_NAME, qb2, params2, 4);
+        Request request2 = constructKNNScriptQueryRequest(INDEX_NAME, qb2, params2, 4, Collections.emptyMap());
         Response response2 = client().performRequest(request2);
         assertEquals(request2.getEndpoint() + ": failed", RestStatus.OK, RestStatus.fromCode(response2.getStatusLine().getStatusCode()));
 
@@ -683,4 +685,110 @@ public void testKNNInnerProdScriptScore() throws Exception {
         assertEquals("4", results.get(2).getDocId());
         assertEquals("1", results.get(3).getDocId());
     }
+
+    public void testKNNScriptScoreWithRequestCacheEnabled() throws Exception {
+        /*
+         * Create knn index and populate data
+         */
+        createKnnIndex(INDEX_NAME, createKnnIndexMapping(FIELD_NAME, 2));
+        Float[] f1 = { 6.0f, 6.0f };
+        addKnnDoc(INDEX_NAME, "1", FIELD_NAME, f1);
+
+        Float[] f2 = { 2.0f, 2.0f };
+        addKnnDoc(INDEX_NAME, "2", FIELD_NAME, f2);
+
+        Float[] f3 = { 4.0f, 4.0f };
+        addKnnDoc(INDEX_NAME, "3", FIELD_NAME, f3);
+
+        Float[] f4 = { 3.0f, 3.0f };
+        addKnnDoc(INDEX_NAME, "4", FIELD_NAME, f4);
+
+        /**
+         * Construct Search Request
+         */
+        QueryBuilder qb = new MatchAllQueryBuilder();
+        Map<String, Object> scriptParams = new HashMap<>();
+        /*
+         *   params": {
+         *       "field": "my_dense_vector",
+         *       "vector": [2.0, 2.0]
+         *      }
+         */
+        float[] queryVector = { 1.0f, 1.0f };
+        scriptParams.put("field", FIELD_NAME);
+        scriptParams.put("query_value", queryVector);
+        scriptParams.put("space_type", SpaceType.L2.getValue());
+        Map<String, Object> searchParams = new HashMap<>();
+        searchParams.put("request_cache", true);
+
+        // first request with request cache enabled
+        Request firstScriptQueryRequest = constructKNNScriptQueryRequest(INDEX_NAME, qb, scriptParams, 4, searchParams);
+        Response firstScriptQueryResponse = client().performRequest(firstScriptQueryRequest);
+        assertEquals(
+            firstScriptQueryRequest.getEndpoint() + ": failed",
+            RestStatus.OK,
+            RestStatus.fromCode(firstScriptQueryResponse.getStatusLine().getStatusCode())
+        );
+
+        List<KNNResult> results = parseSearchResponse(EntityUtils.toString(firstScriptQueryResponse.getEntity()), FIELD_NAME);
+        List<String> expectedDocids = Arrays.asList("2", "4", "3", "1");
+
+        List<String> actualDocids = new ArrayList<>();
+        for (KNNResult result : results) {
+            actualDocids.add(result.getDocId());
+        }
+
+        assertEquals(4, results.size());
+        assertEquals(expectedDocids, actualDocids);
+
+        // assert that the request cache was hit missed at first request
+        Request firstStatsRequest = new Request("GET", "/" + INDEX_NAME + "/_stats");
+        Response firstStatsResponse = client().performRequest(firstStatsRequest);
+        assertEquals(
+            firstStatsRequest.getEndpoint() + ": failed",
+            RestStatus.OK,
+            RestStatus.fromCode(firstStatsResponse.getStatusLine().getStatusCode())
+        );
+        String firstStatsResponseBody = EntityUtils.toString(firstStatsResponse.getEntity());
+        Map<String, Object> firstQueryCacheMap = Optional.ofNullable(
+            createParser(MediaTypeRegistry.getDefaultMediaType().xContent(), firstStatsResponseBody).map()
+        )
+            .map(r -> (Map<String, Object>) r.get("indices"))
+            .map(i -> (Map<String, Object>) i.get(INDEX_NAME))
+            .map(ind -> (Map<String, Object>) ind.get("total"))
+            .map(t -> (Map<String, Object>) t.get("request_cache"))
+            .orElseThrow(() -> new IllegalStateException("Query Cache Map not found"));
+        // assert that the request cache was hit missed at first request
+        assertEquals(1, firstQueryCacheMap.get("miss_count"));
+        assertEquals(0, firstQueryCacheMap.get("hit_count"));
+
+        // second request with request cache enabled
+        Request secondScriptQueryRequest = constructKNNScriptQueryRequest(INDEX_NAME, qb, scriptParams, 4, searchParams);
+        Response secondScriptQueryResponse = client().performRequest(secondScriptQueryRequest);
+        assertEquals(
+            firstScriptQueryRequest.getEndpoint() + ": failed",
+            RestStatus.OK,
+            RestStatus.fromCode(secondScriptQueryResponse.getStatusLine().getStatusCode())
+        );
+
+        Request secondStatsRequest = new Request("GET", "/" + INDEX_NAME + "/_stats");
+        Response secondStatsResponse = client().performRequest(secondStatsRequest);
+        assertEquals(
+            secondStatsRequest.getEndpoint() + ": failed",
+            RestStatus.OK,
+            RestStatus.fromCode(secondStatsResponse.getStatusLine().getStatusCode())
+        );
+        String secondStatsResponseBody = EntityUtils.toString(secondStatsResponse.getEntity());
+        Map<String, Object> secondQueryCacheMap = Optional.ofNullable(
+            createParser(MediaTypeRegistry.getDefaultMediaType().xContent(), secondStatsResponseBody).map()
+        )
+            .map(r -> (Map<String, Object>) r.get("indices"))
+            .map(i -> (Map<String, Object>) i.get(INDEX_NAME))
+            .map(ind -> (Map<String, Object>) ind.get("total"))
+            .map(t -> (Map<String, Object>) t.get("request_cache"))
+            .orElseThrow(() -> new IllegalStateException("Query Cache Map not found"));
+        assertEquals(1, secondQueryCacheMap.get("miss_count"));
+        // assert that the request cache was hit at second request
+        assertEquals(1, secondQueryCacheMap.get("hit_count"));
+    }
 }

src/test/java/org/opensearch/knn/plugin/script/PainlessScriptIT.java

@@ -155,7 +155,15 @@ public void testL2ScriptScoreFails() throws Exception {
     private Request buildPainlessScoreScriptRequest(String source, int size, Map<String, Float[]> documents) throws Exception {
         buildTestIndex(documents);
         QueryBuilder qb = new MatchAllQueryBuilder();
-        return constructScriptScoreContextSearchRequest(INDEX_NAME, qb, Collections.emptyMap(), Script.DEFAULT_SCRIPT_LANG, source, size);
+        return constructScriptScoreContextSearchRequest(
+            INDEX_NAME,
+            qb,
+            Collections.emptyMap(),
+            Script.DEFAULT_SCRIPT_LANG,
+            source,
+            size,
+            Collections.emptyMap()
+        );
     }
 
     private Request buildPainlessScoreScriptRequest(
@@ -166,7 +174,15 @@ private Request buildPainlessScoreScriptRequest(
     ) throws Exception {
         buildTestIndex(documents, properties);
         QueryBuilder qb = new MatchAllQueryBuilder();
-        return constructScriptScoreContextSearchRequest(INDEX_NAME, qb, Collections.emptyMap(), Script.DEFAULT_SCRIPT_LANG, source, size);
+        return constructScriptScoreContextSearchRequest(
+            INDEX_NAME,
+            qb,
+            Collections.emptyMap(),
+            Script.DEFAULT_SCRIPT_LANG,
+            source,
+            size,
+            Collections.emptyMap()
+        );
     }
 
     private Request buildPainlessScriptedMetricRequest(