v.18.16New Feature

New Options for Creating Join Type Tables in ClickHouse

Official CH changelog text
Now you can specify the options join_use_nulls, max_rows_in_join, max_bytes_in_join, and join_overflow_mode when creating a Join type table. Amos Bird
Added support for specifying join_use_nulls, max_rows_in_join, max_bytes_in_join, and join_overflow_mode options when creating a Join type table in ClickHouse.

Why it matters

These options provide users with enhanced control over the behavior and resource limits of Join tables. This helps prevent excessive memory usage and manage join handling more effectively, avoiding potential performance degradation or failures in large join operations.

How to use it

When creating a table with the Join engine, specify the new options in the table definition. For example:

CREATE TABLE join_table
(
    key UInt64,
    value String
)
ENGINE = Join
SETTINGS join_use_nulls = 1, max_rows_in_join = 1000000, max_bytes_in_join = 1000000000, join_overflow_mode = 'any'


Adjust these settings according to your data size and join requirements to control join behavior and resource usage.

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