preferred_* session settings

These settings are available in system.settings and are autogenerated from source.

preferred_block_size_bytes

This setting adjusts the data block size for query processing and represents additional fine-tuning to the more rough ‘max_block_size’ setting. If the columns are large and with ‘max_block_size’ rows the block size is likely to be larger than the specified amount of bytes, its size will be lowered for better CPU cache locality.

preferred_max_column_in_block_size_bytes

Limit on max column size in block while reading. Helps to decrease cache misses count. Should be close to L2 cache size.

preferred_optimize_projection_name

If it is set to a non-empty string, ClickHouse will try to apply specified projection in query.

Possible values:

• string: name of preferred projectio