create table t( f1 Nullable(String), f2 Nullable(Int32), f3 Nullable(String), f4 Nullable(Int32), f5 Nullable(UInt64), f6 Nullable(UInt64), f7 Nullable(String), f8 Nullable(String) ) ENGINE = File(JSONEachRow) insert into t select '3014660362662815', 123, 'xxsdfsdfs', 22, 240321215532916041, 1711036533457, 'xxxxx', 'sdsfsdfsddf' from numbers_mt(1000000) select count(f1) from t settings max_threads=2 drop table t