Enable Point based optimization for custom comparators

Signed-off-by: gashutos <gashutos@amazon.com>

CHANGELOG.md

@@ -82,6 +82,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add descending order search optimization through reverse segment read. ([#7967](https://github.com/opensearch-project/OpenSearch/pull/7967))
 - Update components of segrep backpressure to support remote store. ([#8020](https://github.com/opensearch-project/OpenSearch/pull/8020))
 - Make remote cluster connection setup in async ([#8038](https://github.com/opensearch-project/OpenSearch/pull/8038))
+- Enable Point based optimization for custom comparators ([#8168](https://github.com/opensearch-project/OpenSearch/pull/8168))
 
 ### Dependencies
 - Bump `com.azure:azure-storage-common` from 12.21.0 to 12.21.1 (#7566, #7814)

server/src/main/java/org/opensearch/index/fielddata/IndexNumericFieldData.java

@@ -189,6 +189,14 @@ public final BucketedSort newBucketedSort(
         return newBucketedSort(getNumericType(), bigArrays, missingValue, sortMode, nested, sortOrder, format, bucketSize, extra);
     }
 
+    /**
+     * Should enable BKD based skipping values sort optimization if target numeric type is matching
+     * @param targetNumericType
+     */
+    public boolean enableSortOptimizationForCustomComparators(NumericType targetNumericType) {
+        return this.getNumericType() == targetNumericType;
+    }
+
     /**
      * Build a {@link XFieldComparatorSource} matching the parameters.
      */

server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/DoubleValuesComparatorSource.java

@@ -104,7 +104,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final double dMissingValue = (Double) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new DoubleComparator(numHits, null, null, reversed, false) {
+        return new DoubleComparator(
+            numHits,
+            fieldname,
+            null,
+            reversed,
+            indexFieldData.enableSortOptimizationForCustomComparators(IndexNumericFieldData.NumericType.DOUBLE)
+        ) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new DoubleLeafComparator(context) {

server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/FloatValuesComparatorSource.java

@@ -97,7 +97,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final float fMissingValue = (Float) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new FloatComparator(numHits, null, null, reversed, false) {
+        return new FloatComparator(
+            numHits,
+            fieldname,
+            null,
+            reversed,
+            indexFieldData.enableSortOptimizationForCustomComparators(IndexNumericFieldData.NumericType.FLOAT)
+        ) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new FloatLeafComparator(context) {

server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/IntValuesComparatorSource.java

@@ -76,7 +76,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final int iMissingValue = (Integer) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new IntComparator(numHits, null, null, reversed, false) {
+        return new IntComparator(
+            numHits,
+            fieldname,
+            null,
+            reversed,
+            indexFieldData.enableSortOptimizationForCustomComparators(IndexNumericFieldData.NumericType.INT)
+        ) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new IntLeafComparator(context) {

server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/LongValuesComparatorSource.java

@@ -120,7 +120,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final long lMissingValue = (Long) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new LongComparator(numHits, null, null, reversed, false) {
+        return new LongComparator(
+            numHits,
+            fieldname,
+            null,
+            reversed,
+            indexFieldData.enableSortOptimizationForCustomComparators(IndexNumericFieldData.NumericType.LONG)
+        ) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new LongLeafComparator(context) {

server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/UnsignedLongValuesComparatorSource.java

@@ -92,7 +92,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         assert indexFieldData == null || fieldname.equals(indexFieldData.getFieldName());
 
         final BigInteger ulMissingValue = (BigInteger) missingObject(missingValue, reversed);
-        return new UnsignedLongComparator(numHits, null, null, reversed, false) {
+        return new UnsignedLongComparator(
+            numHits,
+            fieldname,
+            null,
+            reversed,
+            indexFieldData.enableSortOptimizationForCustomComparators(IndexNumericFieldData.NumericType.UNSIGNED_LONG)
+        ) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new UnsignedLongLeafComparator(context) {