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Update query-complexity.md

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docs/en/operations/settings/query-complexity.md
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@ -154,6 +154,13 @@ Result:
Maximum query execution time in seconds.
At this time, it is not checked for one of the sorting stages, or when merging and finalizing aggregate functions.
The `max_execution_time` parameter can be a bit tricky to understand.
It operates based on interpolation relative to the current query execution speed (this behaviour is controlled by [timeout_before_checking_execution_speed](#timeout-before-checking-execution-speed).
ClickHouse will interrupt a query if the projected execution time exceeds the specified max_execution_time.
By default, the timeout_before_checking_execution_speed is set to 1 second. This means that after just one second of query execution, ClickHouse will begin estimating the total execution time. If, for example, `max_execution_time` is set to 3600 seconds (1 hour), ClickHouse will terminate the query if the estimated time exceeds this 3600-second limit.
If you set `timeout_before_checking_execution_speed `to 0, ClickHouse will use clock time as the basis for `max_execution_time`.
## timeout_overflow_mode {#timeout-overflow-mode}
What to do if the query is run longer than ‘max_execution_time’: ‘throw’ or ‘break’. By default, throw.