**Use case**

If FixedString is used with more than 256 bytes in size, it is suspicious and most likely indicates misusage.
Forbid this by default and add a setting to override it; ATTACH queries should allow creating tables nevertheless.

See also: `allow_suspicious_low_cardinality_types`.

M(UInt64, database_replicated_initial_query_timeout_sec, 300, "How long initial DDL query should wait for Replicated database to precess previous DDL queue entries", 0) \
    M(Bool, database_replicated_enforce_synchronous_settings, false, "Enforces synchronous waiting for some queries (see also database_atomic_wait_for_drop_and_detach_synchronously, mutation_sync, replication_alter_partitions_sync). Not recommended to enable these settings.", 0) \
    M(UInt64, max_distributed_depth, 5, "Maximum distributed query depth", 0) \
    M(Bool, database_replicated_always_detach_permanently, false, "Execute DETACH TABLE as DETACH TABLE PERMANENTLY if database engine is Replicated", 0) \
    M(Bool, database_replicated_allow_only_replicated_engine, false, "Allow to create only Replicated tables in database with engine Replicated", 0) \
    M(DistributedDDLOutputMode, distributed_ddl_output_mode, DistributedDDLOutputMode::THROW, "Format of distributed DDL query result", 0) \
    M(UInt64, distributed_ddl_entry_format_version, 3, "Compatibility version of distributed DDL (ON CLUSTER) queries", 0) \
    \
    M(UInt64, external_storage_max_read_rows, 0, "Limit maximum number of rows when table with external engine should flush history data. Now supported only for MySQL table engine, database engine, dictionary and MaterializedMySQL. If equal to 0, this setting is disabled", 0) \
    M(UInt64, external_storage_max_read_bytes, 0, "Limit maximum number of bytes when table with external engine should flush history data. Now supported only for MySQL table engine, database engine, dictionary and MaterializedMySQL. If equal to 0, this setting is disabled", 0)  \
    M(UInt64, external_storage_connect_timeout_sec, DBMS_DEFAULT_CONNECT_TIMEOUT_SEC, "Connect timeout in seconds. Now supported only for MySQL", 0)  \
    M(UInt64, external_storage_rw_timeout_sec, DBMS_DEFAULT_RECEIVE_TIMEOUT_SEC, "Read/write timeout in seconds. Now supported only for MySQL", 0)  \
    \
    M(SetOperationMode, union_default_mode, SetOperationMode::Unspecified, "Set default mode in UNION query. Possible values: empty string, 'ALL', 'DISTINCT'. If empty, query without mode will throw exception.", 0) \
    M(SetOperationMode, intersect_default_mode, SetOperationMode::ALL, "Set default mode in INTERSECT query. Possible values: empty string, 'ALL', 'DISTINCT'. If empty, query without mode will throw exception.", 0) \
    M(SetOperationMode, except_default_mode, SetOperationMode::ALL, "Set default mode in EXCEPT query. Possible values: empty string, 'ALL', 'DISTINCT'. If empty, query without mode will throw exception.", 0) \
    M(Bool, optimize_aggregators_of_group_by_keys, true, "Eliminates min/max/any/anyLast aggregators of GROUP BY keys in SELECT section", 0) \
    M(Bool, optimize_group_by_function_keys, true, "Eliminates functions of other keys in GROUP BY section", 0) \
    M(Bool, legacy_column_name_of_tuple_literal, false, "List all names of element of large tuple literals in their column names instead of hash. This settings exists only for compatibility reasons. It makes sense to set to 'true', while doing rolling update of cluster from version lower than 21.7 to higher.", 0) \
    \
    M(Bool, query_plan_enable_optimizations, true, "Apply optimizations to query plan", 0) \
    M(UInt64, query_plan_max_optimizations_to_apply, 10000, "Limit the total number of optimizations applied to query plan. If zero, ignored. If limit reached, throw exception", 0) \
    M(Bool, query_plan_filter_push_down, true, "Allow to push down filter by predicate query plan step", 0) \
    M(Bool, query_plan_optimize_primary_key, true, "Analyze primary key using query plan (instead of AST)", 0) \
    M(UInt64, regexp_max_matches_per_row, 1000, "Max matches of any single regexp per row, used to safeguard 'extractAllGroupsHorizontal' against consuming too much memory with greedy RE.", 0) \
    \
    M(UInt64, limit, 0, "Limit on read rows from the most 'end' result for select query, default 0 means no limit length", 0) \
    M(UInt64, offset, 0, "Offset on read rows from the most 'end' result for select query", 0) \
    \
    M(UInt64, function_range_max_elements_in_block, 500000000, "Maximum number of values generated by function 'range' per block of data (sum of array sizes for every row in a block, see also 'max_block_size' and 'min_insert_block_size_rows'). It is a safety threshold.", 0) \