Use case:
See #21187
M(Bool, optimize_monotonous_functions_in_order_by, true, "Replace monotonous function with its argument in ORDER BY", 0) \
    M(Bool, normalize_function_names, true, "Normalize function names to their canonical names", 0) \
    M(Bool, allow_experimental_alter_materialized_view_structure, false, "Allow atomic alter on Materialized views. Work in progress.", 0) \
    M(Bool, enable_early_constant_folding, true, "Enable query optimization where we analyze function and subqueries results and rewrite query if there're constants there", 0) \
    M(Bool, deduplicate_blocks_in_dependent_materialized_views, false, "Should deduplicate blocks for materialized views if the block is not a duplicate for the table. Use true to always deduplicate in dependent tables.", 0) \
    M(Bool, use_compact_format_in_distributed_parts_names, true, "Changes format of directories names for distributed table insert parts.", 0) \
    M(Bool, validate_polygons, true, "Throw exception if polygon is invalid in function pointInPolygon (e.g. self-tangent, self-intersecting). If the setting is false, the function will accept invalid polygons but may silently return wrong result.", 0) \
    M(UInt64, max_parser_depth, DBMS_DEFAULT_MAX_PARSER_DEPTH, "Maximum parser depth (recursion depth of recursive descend parser).", 0) \
    M(Seconds, temporary_live_view_timeout, DEFAULT_TEMPORARY_LIVE_VIEW_TIMEOUT_SEC, "Timeout after which temporary live view is deleted.", 0) \
    M(Seconds, periodic_live_view_refresh, DEFAULT_PERIODIC_LIVE_VIEW_REFRESH_SEC, "Interval after which periodically refreshed live view is forced to refresh.", 0) \
    M(Bool, transform_null_in, false, "If enabled, NULL values will be matched with 'IN' operator as if they are considered equal.", 0) \
    M(Bool, allow_nondeterministic_mutations, false, "Allow non-deterministic functions in ALTER UPDATE/ALTER DELETE statements", 0) \
    M(Seconds, lock_acquire_timeout, DBMS_DEFAULT_LOCK_ACQUIRE_TIMEOUT_SEC, "How long locking request should wait before failing", 0) \
    M(Bool, materialize_ttl_after_modify, true, "Apply TTL for old data, after ALTER MODIFY TTL query", 0) \
    M(String, function_implementation, "", "Choose function implementation for specific target or variant (experimental). If empty enable all of them.", 0) \
    M(Bool, allow_experimental_geo_types, false, "Allow geo data types such as Point, Ring, Polygon, MultiPolygon", 0) \
    M(Bool, allow_experimental_bigint_types, false, "Allow Int128, Int256, UInt256 and Decimal256 types", 0) \
    M(Bool, data_type_default_nullable, false, "Data types without NULL or NOT NULL will make Nullable", 0) \
    M(Bool, cast_keep_nullable, false, "CAST operator keep Nullable for result data type", 0) \
    M(Bool, alter_partition_verbose_result, false, "Output information about affected parts. Currently works only for FREEZE and ATTACH commands.", 0) \
    M(Bool, allow_experimental_database_materialize_mysql, false, "Allow to create database with Engine=MaterializeMySQL(...).", 0) \
    M(Bool, system_events_show_zero_values, false, "Include all metrics, even with zero values", 0) \
    M(MySQLDataTypesSupport, mysql_datatypes_support_level, 0, "Which MySQL types should be converted to corresponding ClickHouse types (rather than being represented as String). Can be empty or any combination of 'decimal' or 'datetime64'. When empty MySQL's DECIMAL and DATETIME/TIMESTAMP with non-zero precision are seen as String on ClickHouse's side.", 0) \
    M(Bool, optimize_trivial_insert_select, true, "Optimize trivial 'INSERT INTO table SELECT ... FROM TABLES' query", 0) \
    M(Bool, allow_non_metadata_alters, true, "Allow to execute alters which affects not only tables metadata, but also data on disk", 0) \
    M(Bool, enable_global_with_statement, true, "Propagate WITH statements to UNION queries and all subqueries", 0) \
    M(Bool, aggregate_functions_null_for_empty, false, "Rewrite all aggregate functions in a query, adding -OrNull suffix to them", 0) \
    M(Bool, flatten_nested, true, "If true, columns of type Nested will be flatten to separate array columns instead of one array of tuples", 0) \
    M(Bool, asterisk_include_materialized_columns, false, "Include MATERIALIZED columns for wildcard query", 0) \
    M(Bool, asterisk_include_alias_columns, false, "Include ALIAS columns for wildcard query", 0) \