prefer_fetch_* MergeTree table settings

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

prefer_fetch_merged_part_size_threshold

If the sum of the size of parts exceeds this threshold and the time since a replication log entry creation is greater than prefer_fetch_merged_part_time_threshold, then prefer fetching merged part from a replica instead of doing merge locally. This is to speed up very long merges.

Possible values:

• Any positive integer.

prefer_fetch_merged_part_time_threshold

If the time passed since a replication log (ClickHouse Keeper or ZooKeeper) entry creation exceeds this threshold, and the sum of the size of parts is greater than prefer_fetch_merged_part_size_threshold, then prefer fetching merged part from a replica instead of doing merge locally. This is to speed up very long merges.

Possible values:

• Any positive integer.