diff --git a/src/Core/Settings.h b/src/Core/Settings.h
index dc4b860ce44..215e5b38056 100644
--- a/src/Core/Settings.h
+++ b/src/Core/Settings.h
@@ -745,7 +745,7 @@ class IColumn;
     M(Bool, implicit_transaction, false, "If enabled and not already inside a transaction, wraps the query inside a full transaction (begin + commit or rollback)", 0) \
     M(UInt64, grace_hash_join_initial_buckets, 1, "Initial number of grace hash join buckets", 0) \
     M(UInt64, grace_hash_join_max_buckets, 1024, "Limit on the number of grace hash join buckets", 0) \
-    M(Bool, optimize_distinct_in_order, false, "This optimization has a bug and it is disabled. Enable DISTINCT optimization if some columns in DISTINCT form a prefix of sorting. For example, prefix of sorting key in merge tree or ORDER BY statement", 0) \
+    M(Bool, optimize_distinct_in_order, true, "Enable DISTINCT optimization if some columns in DISTINCT form a prefix of sorting. For example, prefix of sorting key in merge tree or ORDER BY statement", 0) \
     M(Bool, allow_experimental_undrop_table_query, false, "Allow to use undrop query to restore dropped table in a limited time", 0) \
     M(Bool, keeper_map_strict_mode, false, "Enforce additional checks during operations on KeeperMap. E.g. throw an exception on an insert for already existing key", 0) \
     // End of COMMON_SETTINGS