**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`.

* Almost all limits apply only to SELECTs. \
      * Almost all limits apply to each stream individually. \
      */ \
    \
    M(UInt64, max_rows_to_read, 0, "Limit on read rows from the most 'deep' sources. That is, only in the deepest subquery. When reading from a remote server, it is only checked on a remote server.", 0) \
    M(UInt64, max_bytes_to_read, 0, "Limit on read bytes (after decompression) from the most 'deep' sources. That is, only in the deepest subquery. When reading from a remote server, it is only checked on a remote server.", 0) \
    M(OverflowMode, read_overflow_mode, OverflowMode::THROW, "What to do when the limit is exceeded.", 0) \
    \
    M(UInt64, max_rows_to_read_leaf, 0, "Limit on read rows on the leaf nodes for distributed queries. Limit is applied for local reads only excluding the final merge stage on the root node.", 0) \
    M(UInt64, max_bytes_to_read_leaf, 0, "Limit on read bytes (after decompression) on the leaf nodes for distributed queries. Limit is applied for local reads only excluding the final merge stage on the root node.", 0) \
    M(OverflowMode, read_overflow_mode_leaf, OverflowMode::THROW, "What to do when the leaf limit is exceeded.", 0) \
    \
    M(UInt64, max_rows_to_group_by, 0, "If aggregation during GROUP BY is generating more than specified number of rows (unique GROUP BY keys), the behavior will be determined by the 'group_by_overflow_mode' which by default is - throw an exception, but can be also switched to an approximate GROUP BY mode.", 0) \
    M(OverflowModeGroupBy, group_by_overflow_mode, OverflowMode::THROW, "What to do when the limit is exceeded.", 0) \
    M(UInt64, max_bytes_before_external_group_by, 0, "If memory usage during GROUP BY operation is exceeding this threshold in bytes, activate the 'external aggregation' mode (spill data to disk). Recommended value is half of available system memory.", 0) \
    \
    M(UInt64, max_rows_to_sort, 0, "If more than specified amount of records have to be processed for ORDER BY operation, the behavior will be determined by the 'sort_overflow_mode' which by default is - throw an exception", 0) \
    M(UInt64, max_bytes_to_sort, 0, "If more than specified amount of (uncompressed) bytes have to be processed for ORDER BY operation, the behavior will be determined by the 'sort_overflow_mode' which by default is - throw an exception", 0) \
    M(OverflowMode, sort_overflow_mode, OverflowMode::THROW, "What to do when the limit is exceeded.", 0) \
    M(UInt64, max_bytes_before_external_sort, 0, "If memory usage during ORDER BY operation is exceeding this threshold in bytes, activate the 'external sorting' mode (spill data to disk). Recommended value is half of available system memory.", 0) \
    M(UInt64, max_bytes_before_remerge_sort, 1000000000, "In case of ORDER BY with LIMIT, when memory usage is higher than specified threshold, perform additional steps of merging blocks before final merge to keep just top LIMIT rows.", 0) \
    M(Float, remerge_sort_lowered_memory_bytes_ratio, 2., "If memory usage after remerge does not reduced by this ratio, remerge will be disabled.", 0) \
    \
    M(UInt64, max_result_rows, 0, "Limit on result size in rows. Also checked for intermediate data sent from remote servers.", 0) \
    M(UInt64, max_result_bytes, 0, "Limit on result size in bytes (uncompressed). Also checked for intermediate data sent from remote servers.", 0) \
    M(OverflowMode, result_overflow_mode, OverflowMode::THROW, "What to do when the limit is exceeded.", 0) \
    \
    /* TODO: Check also when merging and finalizing aggregate functions. */ \
    M(Seconds, max_execution_time, 0, "If query run time exceeded the specified number of seconds, the behavior will be determined by the 'timeout_overflow_mode' which by default is - throw an exception. Note that the timeout is checked and query can stop only in designated places during data processing. It currently cannot stop during merging of aggregation states or during query analysis, and the actual run time will be higher than the value of this setting.", 0) \
    M(OverflowMode, timeout_overflow_mode, OverflowMode::THROW, "What to do when the limit is exceeded.", 0) \