update_* session settings

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

update_parallel_mode

Determines the behavior of concurrent update queries. Possible values:

sync - run sequentially all UPDATE queries.
auto - run sequentially only UPDATE queries with dependencies between columns updated in one query and columns used in expressions of another query.
async - do not synchronize update queries.

If true set of parts is updated to the latest version before execution of update.