for i in {1..100};doecho"ALTER TABLE concurrent_alter_column ADD COLUMN d DOUBLE"|${CLICKHOUSE_CLIENT}; sleep `echo 0.0$RANDOM`;echo"ALTER TABLE concurrent_alter_column DROP COLUMN d"|${CLICKHOUSE_CLIENT} -n;done&
for i in {1..100};doecho"ALTER TABLE concurrent_alter_column ADD COLUMN e DOUBLE"|${CLICKHOUSE_CLIENT}; sleep `echo 0.0$RANDOM`;echo"ALTER TABLE concurrent_alter_column DROP COLUMN e"|${CLICKHOUSE_CLIENT} -n;done&
for i in {1..100};doecho"ALTER TABLE concurrent_alter_column ADD COLUMN f DOUBLE"|${CLICKHOUSE_CLIENT}; sleep `echo 0.0$RANDOM`;echo"ALTER TABLE concurrent_alter_column DROP COLUMN f"|${CLICKHOUSE_CLIENT} -n;done&