diff --git a/src/Core/Settings.h b/src/Core/Settings.h
index 42b52695a5c..3f1ecc47f79 100644
--- a/src/Core/Settings.h
+++ b/src/Core/Settings.h
@@ -602,7 +602,7 @@ class IColumn;
     M(Bool, optimize_if_chain_to_multiif, false, "Replace if(cond1, then1, if(cond2, ...)) chains to multiIf. Currently it's not beneficial for numeric types.", 0) \
     M(Bool, optimize_multiif_to_if, true, "Replace 'multiIf' with only one condition to 'if'.", 0) \
     M(Bool, optimize_if_transform_strings_to_enum, false, "Replaces string-type arguments in If and Transform to enum. Disabled by default cause it could make inconsistent change in distributed query that would lead to its fail.", 0) \
-    M(Bool, optimize_functions_to_subcolumns, true, "Transform functions to subcolumns, if possible, to reduce amount of read data. E.g. 'length(arr)' -> 'arr.size0', 'col IS NULL' -> 'col.null' ", 0) \
+    M(Bool, optimize_functions_to_subcolumns, false, "Transform functions to subcolumns, if possible, to reduce amount of read data. E.g. 'length(arr)' -> 'arr.size0', 'col IS NULL' -> 'col.null' ", 0) \
     M(Bool, optimize_using_constraints, false, "Use constraints for query optimization", 0)                                                                                                                                           \
     M(Bool, optimize_substitute_columns, false, "Use constraints for column substitution", 0)                                                                                                                                         \
     M(Bool, optimize_append_index, false, "Use constraints in order to append index condition (indexHint)", 0) \
diff --git a/src/Core/SettingsChangesHistory.cpp b/src/Core/SettingsChangesHistory.cpp
index 15849b5a5df..acd119c159b 100644
--- a/src/Core/SettingsChangesHistory.cpp
+++ b/src/Core/SettingsChangesHistory.cpp
@@ -63,7 +63,6 @@ static std::initializer_list<std::pair<ClickHouseVersion, SettingsChangesHistory
               {"output_format_native_encode_types_in_binary_format", false, false, "Added new setting to allow to write type names in binary format in Native output format"},
               {"input_format_native_decode_types_in_binary_format", false, false, "Added new setting to allow to read type names in binary format in Native output format"},
               {"read_in_order_use_buffering", false, true, "Use buffering before merging while reading in order of primary key"},
-              {"optimize_functions_to_subcolumns", false, true, "Enable optimization by default"},
               {"enable_named_columns_in_function_tuple", false, true, "Generate named tuples in function tuple() when all names are unique and can be treated as unquoted identifiers."},
               {"input_format_json_ignore_key_case", false, false, "Ignore json key case while read json field from string."},
               {"optimize_trivial_insert_select", true, false, "The optimization does not make sense in many cases."},
diff --git a/tests/clickhouse-test b/tests/clickhouse-test
index 0c04d8fb2c3..a29c786e998 100755
--- a/tests/clickhouse-test
+++ b/tests/clickhouse-test
@@ -835,6 +835,7 @@ class SettingsRandomizer:
         "cross_join_min_bytes_to_compress": lambda: random.choice([0, 1, 100000000]),
         "min_external_table_block_size_bytes": lambda: random.choice([0, 1, 100000000]),
         "max_parsing_threads": lambda: random.choice([0, 1, 10]),
+        "optimize_functions_to_subcolumns": lambda: random.randint(0, 1),
     }
 
     @staticmethod