timeout_overflow_mode_* session settings

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

timeout_overflow_mode

Sets what to do if the query is run longer than the max_execution_time or the estimated running time is longer than max_estimated_execution_time (the estimate is only checked with throw).

Possible values:

• throw: throw an exception (default).
• break: stop executing the query and return the partial result, as if the source data ran out. Some operations cannot return a partial result safely, so instead of a smaller result they stop without producing one. A function computing a single value stops without producing that value; whether the stop also reaches the client as a TIMEOUT_EXCEEDED error, or only as a missing result, depends on where the query was interrupted. A Memory-table mutation left incomplete by the timeout keeps the table unchanged and reports TIMEOUT_EXCEEDED. An INSERT may report QUERY_WAS_CANCELLED. Some operations that wait for other replicas or for background work do not stop at max_execution_time at all: a quorum write keeps waiting until its quorum is satisfied, or reports UNKNOWN_STATUS_OF_INSERT if insert_quorum_timeout elapses first.

timeout_overflow_mode_leaf

Sets what happens when the query in leaf node run longer than max_execution_time_leaf.

Possible values:

• throw: throw an exception (default).
• break: stop executing the query and return the partial result, as if the source data ran out. Some operations cannot return a partial result safely, so instead of a smaller result they stop without producing one: a function computing a single value stops without producing that value. Whether such a stop also reaches the client as a TIMEOUT_EXCEEDED error, or only as a missing result, depends on where the query was interrupted.