CREATE TABLE mv_source (a Int64, insert_time DateTime) ENGINE = MergeTree() ORDER BY insert_time;
CREATE TABLE mv_target (a Int64, insert_time DateTime) ENGINE = MergeTree() ORDER BY insert_time;
CREATE MATERIALIZED VIEW source_to_target to mv_target as Select * from mv_source where a not in (Select sleepEachRow(0.1) from numbers(50));

ALTER TABLE mv_source MODIFY TTL insert_time + toIntervalDay(1);
SYSTEM FLUSH LOGS;
-- This is a fancy way to check that the MV hasn't been called (no functions executed by ALTER)
SELECT
    ProfileEvents['FunctionExecute'],
    ProfileEvents['TableFunctionExecute']
FROM system.query_log
WHERE
        type = 'QueryFinish' AND
        query like '%ALTER TABLE mv_source%' AND
        current_database = currentDatabase() AND
        event_time > now() - INTERVAL 10 minute;