TSQL query is running slow, how to speed it up? - sql

Question

I have a sql query for a report, it includes a few sub queries. it runs very slow. I tried a few ways (like use join instead of subquery, add a few more index). but none of them worked. Here is the query:
declare #time_from datetime
declare #time_to datetime
set #time_from ='2012-01-01'
set #time_to = '2014-01-01'
select a.a_id, c.c_id, c.c_chat_line_id, a.a_first_name, a.a_last_name
,(select isnull(SUM(ac.ac_amount),0) from t_actress_credit ac join t_order o on o.o_id = ac.order_id where o.o_status = 1 and ac.actress_id = a.a_id and ac.ac_time>=#time_from and ac.ac_time<=#time_to) as credit
,(select isnull(SUM(ac.ac_amount),0) from t_actress_credit ac join t_order o on o.o_id = ac.order_id where o.o_status = 1 and ac.ac_is_paid = 1 and ac.actress_id = a.a_id and ac.ac_time>=#time_from and ac.ac_time<=#time_to) as paid_credit
,(select COUNT(1) from t_message pm join t_call_log l1 on pm.call_log_id = l1.c_id where pm.m_type = 2 and l1.caller_id = c.c_id and pm.m_time>=#time_from and pm.m_time<=#time_to) as pmsg_sent
,(select COUNT(1) from t_message pm join t_call_log l2 on pm.m_to_call_log_id = l2.c_id where pm.m_type = 2 and l2.caller_id = c.c_id and pm.m_time>=#time_from and pm.m_time<=#time_to) as pmsg_received
,(select COUNT(1) from t_message pm join t_call_log l3 on pm.call_log_id = l3.c_id where pm.m_type = 1 and l3.caller_id = c.c_id and pm.m_time>=#time_from and pm.m_time<=#time_to) as lcmsg_sent
,(select COUNT(1) from t_message pm join t_call_log l4 on pm.m_to_call_log_id = l4.c_id where pm.m_type = 1 and l4.caller_id = c.c_id and pm.m_time>=#time_from and pm.m_time<=#time_to) as lcmsg_received
,(select COUNT(1) from t_actress_live_minute where actress_id = a.a_id and alm_time>=#time_from and alm_time<=#time_to ) as live_calls
,(select isnull(SUM(alm_minutes),0) from t_actress_live_minute where actress_id = a.a_id and alm_time>=#time_from and alm_time<=#time_to) as live_call_minutes
,(select isnull(count(1),0) from t_call_log l where l.caller_id = c.c_id and l.c_time_out is not null and c_time_in >=#time_from and c_time_in <= #time_to) as total_calls
,(select isnull(SUM(DATEDIFF(minute, l.c_time_in, l.c_time_out)),0) from t_call_log l where c_time_in >=#time_from and c_time_in <= #time_to and l.caller_id = c.c_id and l.c_time_out is not null ) as total_call_minutes
from t_actress a
join t_caller c on c.c_id = a.caller_id
group by a.a_id,c.c_id, c.c_chat_line_id, a.a_first_name, a.a_last_name
Can any one give some suggestions?
Thanks a lot!
Alan

Answer 1

You could try combining subqueries that pull from the same table or set of tables into a single subquery. To account for variations in the conditions, you could use conditional aggregation (employing CASE expressions).
I can see four, possibly five, such groups in your query. Here it is rewritten to use four subqueries:
SELECT
a.a_id,
c.c_id,
c.c_chat_line_id,
a.a_first_name,
a.a_last_name,
ISNULL(cr.credit , 0) AS credit
ISNULL(cr.paid_credit , 0) AS paid_credit
ISNULL(m.pmsg_sent , 0) AS pmsg_sent,
ISNULL(m.pmsg_received , 0) AS pmsg_received,
ISNULL(m.lcmsg_sent , 0) AS lcmsg_sent,
ISNULL(m.lcmsg_received , 0) AS lcmsg_received,
ISNULL(alm.live_calls , 0) AS live_calls,
ISNULL(alm.live_call_minutes, 0) AS live_call_minutes,
ISNULL(l.total_calls , 0) AS total_calls,
ISNULL(l.total_call_minutes , 0) AS total_call_minutes,
FROM t_actress AS a
INNER JOIN t_caller AS c
ON c.c_id = a.caller_id
LEFT JOIN (
SELECT
ac.actress_id,
SUM( ac.ac_amount ) AS credit,
SUM(CASE ac.ac_is_paid WHEN 1 THEN ac.ac_amount END) AS paid_credit
FROM t_actress_credit AS ac
JOIN t_order o ON o.o_id = ac.order_id
WHERE o.o_status = 1
AND ac.ac_time BETWEEN #time_from AND #time_to
GROUP BY ac.actress_id
) AS ac
ON ac.actress_id = a.a_id
LEFT JOIN (
SELECT
l.caller_id,
COUNT(CASE WHEN m. call_log_id = l1.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l2.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_received,
COUNT(CASE WHEN m. call_log_id = l3.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l4.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_received
FROM t_message AS m
JOIN t_call_log AS l ON l.c_id IN (m.call_log_id, m.m_to_call_log_id)
WHERE m.m_type IN (1, 2)
AND m.m_time BETWEEN #time_from AND #time_to
GROUP BY l.caller_id
) AS m
ON m.caller_id = c.c_id
LEFT JOIN (
SELECT
actress_id,
COUNT(*) AS live_calls,
SUM(alm_minutes) AS live_call_minutes
FROM t_actress_live_minute
WHERE alm_time BETWEEN #time_from AND #time_to
GROUP BY actress_id
) AS alm
ON alm.actress_id = a.a_id
LEFT JOIN (
SELECT
caller_id,
COUNT(*) AS total_calls,
SUM(DATEDIFF(MINUTE, c_time_in, c_time_out)) AS total_call_minutes
FROM t_call_log
WHERE c_time_out IS NOT NULL
AND c_time_in BETWEEN #time_from AND #time_to
GROUP BY caller_id
) AS l
ON l.actress_id = a.a_id
;
It could be five subqueries if you split the m subquery into two by joining separately on call_log_id and on m_to_call_log_id (and thus potentially giving the query planner more room for optimisation), i.e. instead of
LEFT JOIN (
SELECT
l.caller_id,
COUNT(CASE WHEN m. call_log_id = l1.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l2.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_received,
COUNT(CASE WHEN m. call_log_id = l3.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l4.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_received
FROM t_message AS m
JOIN t_call_log AS l ON l.c_id IN (m.call_log_id, m.m_to_call_log_id)
WHERE m.m_type IN (1, 2)
AND m.m_time BETWEEN #time_from AND #time_to
GROUP BY l.caller_id
) AS m
ON m.caller_id = c.c_id
it would be
LEFT JOIN (
SELECT
l.caller_id,
COUNT(CASE WHEN m.call_log_id = l1.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_sent,
COUNT(CASE WHEN m.call_log_id = l3.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_sent,
FROM t_message AS m
JOIN t_call_log AS l ON l.c_id = m.call_log_id
WHERE m.m_type IN (1, 2)
AND m.m_time BETWEEN #time_from AND #time_to
GROUP BY l.caller_id
) AS mf
ON mf.caller_id = c.c_id
LEFT JOIN (
SELECT
l.caller_id,
COUNT(CASE WHEN m.m_to_call_log_id = l2.c_id AND m.m_type = 2 THEN 1 END) AS pmsg_received,
COUNT(CASE WHEN m.m_to_call_log_id = l4.c_id AND m.m_type = 1 THEN 1 END) AS lcmsg_received
FROM t_message AS m
JOIN t_call_log AS l ON l.c_id = m.m_to_call_log_id
WHERE m.m_type IN (1, 2)
AND m.m_time BETWEEN #time_from AND #time_to
GROUP BY l.caller_id
) AS mt
ON mt.caller_id = c.c_id
changing also the corresponding references in the main SELECT clause.
I'm not sure whether which of the variations is better, you'll need to test both to find out.
Note that I've omitted the main query's GROUP BY clause. It seems unnecessary both in your query and in mine, because, as far as I can see, it includes primary keys from both t_actress and t_caller and those combinations would be unique anyway. I assume that the GROUP BY is a leftover from your previous attempts at rewriting the query using joins.

Answer 2

thanks for your reply. I tried your way, it is still slow. here is what I did and finally works. I basically put all the sub queries into table, and then join the table at the end. not sure why, but it is faster: here is the code;
-- total calls
declare #t_call table(
a_id bigint,
total_calls bigint,
total_call_minutes bigint
);
insert into #t_call
SELECT a_id, COUNT(1) AS total_calls, isnull(SUM(DATEDIFF(MINUTE, c_time_in, c_time_out)),0) AS total_call_minutes
FROM t_actress aa
join t_call_log l on aa.caller_id = l.caller_id and c_time_in BETWEEN #time_from AND #time_to and c_time_out IS NOT NULL
GROUP BY a_id;
-- total live minutes
declare #t_live table(
a_id bigint,
live_calls bigint,
live_call_minutes bigint
);
insert into #t_live
SELECT a_id, COUNT(*) AS live_calls, isnull(SUM(alm_minutes),0) AS live_call_minutes
FROM t_actress a
join t_actress_live_minute alm on alm.actress_id = a.a_id and alm_time BETWEEN #time_from AND #time_to
GROUP BY a_id
-- total message by caller
declare #t_cm table(
caller_id bigint,
pmsg_sent bigint,
pmsg_received bigint,
lcmsg_sent bigint,
lcmsg_received bigint
)
insert into #t_cm
SELECT l.caller_id,
COUNT(CASE WHEN m.call_log_id = l.c_id AND m.m_type = 2 THEN 1 END) AS _pmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l.c_id AND m.m_type = 2 THEN 1 END) AS _pmsg_received,
COUNT(CASE WHEN m.call_log_id = l.c_id AND m.m_type = 1 THEN 1 END) AS _lcmsg_sent,
COUNT(CASE WHEN m.m_to_call_log_id = l.c_id AND m.m_type = 1 THEN 1 END) AS _lcmsg_received
FROM t_message m
join t_call_log l on l.c_id in (m.call_log_id, m.m_to_call_log_id)
where m.m_time BETWEEN #time_from AND #time_to
GROUP BY l.caller_id
-- total message by actress
declare #t_msg table(
a_id bigint,
pmsg_sent bigint,
pmsg_received bigint,
lcmsg_sent bigint,
lcmsg_received bigint
)
insert into #t_msg
select a_id, isnull(SUM(cm.pmsg_sent),0), isnull(SUM(cm.pmsg_received),0), isnull(SUM(cm.lcmsg_sent),0), isnull(SUM(cm.lcmsg_received),0)
from t_actress a
join #t_cm cm on a.caller_id = cm.caller_id
group by a_id
-- total credit
declare #t_credit table(
a_id bigint,
credit money,
paid_credit money
)
insert into #t_credit
SELECT a_id, isnull(SUM(ac.ac_amount),0) AS credit, isnull(SUM(CASE ac.ac_is_paid WHEN 1 THEN ac.ac_amount else 0 END),0) AS paid_credit
FROM t_actress a
join t_actress_credit ac on ac.actress_id = a.a_id AND ac.ac_time BETWEEN #time_from AND #time_to
JOIN t_order o ON o.o_id = ac.order_id and o_status = 1
GROUP BY a_id
-- the report
select a.a_id, cl.c_id, cl.c_chat_line_id, a.a_first_name, a.a_last_name,
isnull(ac.credit,0) credit, isnull(ac.paid_credit,0) paid_credit,
isnull(m.pmsg_sent,0) pmsg_sent, isnull(m.pmsg_received,0) pmsg_received, isnull(m.lcmsg_sent,0) lcmsg_sent, isnull(m.lcmsg_received,0) lcmsg_received,
isnull(l.live_calls,0) live_calls, isnull(l.live_call_minutes,0) live_call_minutes,
isnull(c.total_calls,0) total_calls, isnull(c.total_call_minutes,0) total_call_minutes
from t_actress a
join t_caller cl on cl.c_id = a.caller_id
left outer join #t_call c on c.a_id = a.a_id
left outer join #t_live l on l.a_id = a.a_id
left outer join #t_msg m on m.a_id = a.a_id
left outer join #t_credit ac on ac.a_id = a.a_id
order by a_id