From f7b3ba3a4e81e46e493c34d7eab31f71e7d64ac6 Mon Sep 17 00:00:00 2001
From: Sarthak Aggarwal <sarthagg@amazon.com>
Date: Wed, 19 Jul 2023 15:14:39 +0530
Subject: [PATCH] reinstating default and best_compression

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>
---
 .../main/java/org/opensearch/index/codec/CodecService.java  | 6 ++++++
 .../main/java/org/opensearch/index/engine/EngineConfig.java | 5 ++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/opensearch/index/codec/CodecService.java b/server/src/main/java/org/opensearch/index/codec/CodecService.java
index 13b7accf4ac69..0bad6b504a89b 100644
--- a/server/src/main/java/org/opensearch/index/codec/CodecService.java
+++ b/server/src/main/java/org/opensearch/index/codec/CodecService.java
@@ -67,6 +67,8 @@ public class CodecService {
      * the raw unfiltered lucene default. useful for testing
      */
     public static final String LUCENE_DEFAULT_CODEC = "lucene_default";
+    public static final String DEFAULT = "default";
+    public static final String BEST_COMPRESSION = "best_compression";
     public static final String ZSTD_CODEC = "zstd";
     public static final String ZSTD_NO_DICT_CODEC = "zstd_no_dict";
 
@@ -80,12 +82,16 @@ public CodecService(@Nullable MapperService mapperService, IndexSettings indexSe
         }
         if (mapperService == null) {
             codecs.put(LZ4_CODEC, new Lucene95Codec());
+            codecs.put(DEFAULT, new Lucene95Codec());
             codecs.put(ZLIB_CODEC, new Lucene95Codec(Mode.BEST_COMPRESSION));
+            codecs.put(BEST_COMPRESSION, new Lucene95Codec(Mode.BEST_COMPRESSION));
             codecs.put(ZSTD_CODEC, new ZstdCodec(compressionLevel));
             codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(compressionLevel));
         } else {
             codecs.put(LZ4_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
+            codecs.put(DEFAULT, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
             codecs.put(ZLIB_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
+            codecs.put(BEST_COMPRESSION, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
             codecs.put(ZSTD_CODEC, new ZstdCodec(mapperService, logger, compressionLevel));
             codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(mapperService, logger, compressionLevel));
         }
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
index 68403b146c435..4ac06524ee755 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
@@ -131,6 +131,8 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
     public static final Setting<String> INDEX_CODEC_SETTING = new Setting<>("index.codec", "lz4", s -> {
         switch (s) {
             case "lz4":
+            case "default":
+            case "best_compression":
             case "zlib":
             case "zstd":
             case "zstd_no_dict":
@@ -139,7 +141,8 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
             default:
                 if (Codec.availableCodecs().contains(s) == false) { // we don't error message the not officially supported ones
                     throw new IllegalArgumentException(
-                        "unknown value for [index.codec] must be one of [lz4, zlib, zstd, zstd_no_dict] but was: " + s
+                        "unknown value for [index.codec] must be one of [default, best_compression, lz4, zlib, zstd, zstd_no_dict] but was: "
+                            + s
                     );
                 }
                 return s;