How to increase performance of complicated MySQL select query? - mysql

Question

I am working on project management tool and while generating reports through admin end the loading time for the data from the database is very much > 5 minutes. There are few points which I know would help me to increase the performance but right now I need to have the help in SELECT query
SELECT timesheet_client.organisation as client_name, timesheet_project.title as project_name,
timesheet_task.name as task, CONCAT(timesheet_user.first_name, ' ', timesheet_user.last_name) as resource_name,
timesheet_user.bill_factor, timesheet_client.client_type, sum(spent) as spent, sum(delivered_hours) as delivered_hours,
sum(billable_hours) as billable_hours, comments, color, lock_color, updated_by, updated_by_date, timesheet_user_psdb.grp_id,
timesheet_user_psdb.client_id, timesheet_user_psdb.proj_id, timesheet_user_psdb.task_id, timesheet_user_psdb.uid,
timesheet_user_grp.grp_name
FROM timesheet_user_psdb,timesheet_user, timesheet_client,
timesheet_project,timesheet_task,timesheet_user_grp
WHERE timesheet_user.username=timesheet_user_psdb.uid and
timesheet_client.client_id=timesheet_user_psdb.client_id and timesheet_project.proj_id=timesheet_user_psdb.proj_id and
timesheet_task.task_id = timesheet_user_psdb.task_id and timesheet_user_grp.grp_id=timesheet_user_psdb.grp_id and month =3
AND year = 2017 and month!='' and timesheet_user_psdb.client_id=326
GROUP BY timesheet_user_psdb.task_id,timesheet_user_psdb.uid
ORDER BY timesheet_client.client_type desc,timesheet_client.organisation,timesheet_user_psdb.proj_id,
timesheet_user_psdb.task_id,timesheet_user.uid,timesheet_user_psdb.task_id;
I have already used an index on all the primary keys.
EXPLAIN Output:
Help for this would be highly appreciable.

Answer 1

Give this a try:
SELECT
TC.ORGANISATION AS CLIENT_NAME,
TP.TITLE AS PROJECT_NAME,
TT.NAME AS TASK,
CONCAT(TU.FIRST_NAME, ' ', TU.LAST_NAME) AS RESOURCE_NAME,
TU.BILL_FACTOR,
TC.CLIENT_TYPE, SUM(SPENT) AS SPENT, -- You should specify which table this comes from
SUM(DELIVERED_HOURS) AS DELIVERED_HOURS, -- You should specify which table this comes from
SUM(BILLABLE_HOURS) AS BILLABLE_HOURS, -- You should specify which table this comes from
COMMENTS, -- You should specify which table this comes from
COLOR, -- You should specify which table this comes from
LOCK_COLOR, -- You should specify which table this comes from
UPDATED_BY, -- You should specify which table this comes from
UPDATED_BY_DATE, -- You should specify which table this comes from
TUP.GRP_ID,
TUP.CLIENT_ID,
TUP.PROJ_ID,
TUP.TASK_ID,
TUP.UID,
TUG.GRP_NAME
FROM
TIMESHEET_USER AS TU
LEFT OUTER JOIN
TIMESHEET_USER_PSDB AS TUP
ON TU.USERNAME = TUP.UID
LEFT OUTER JOIN
TIMESHEET_USER_GRP AS TUG
ON TUP.GRP_ID = TUG.GRP_ID
LEFT OUTER JOIN
TIMESHEET_CLIENT AS TC
ON TUP.CLIENT_ID = TC.CLIENT_ID
LEFT OUTER JOIN
TIMESHEET_PROJECT AS TP
ON TUP.PROJ_ID = TP.PROJ_ID
LEFT OUTER JOIN
TIMESHEET_TASK TT
ON TUP.TASK_ID = TT.TASK_ID
WHERE
MONTH = 3 AND -- You should specify which table this comes from
YEAR = 2017 AND -- You should specify which table this comes from
MONTH != '' AND -- You should specify which table this comes from
TUP.CLIENT_ID = 326
GROUP BY
TUP.TASK_ID,
TUP.UID
ORDER BY
TC.CLIENT_TYPE DESC,
TC.ORGANISATION,
TUP.PROJ_ID,
TUP.TASK_ID,
TU.UID,
TUP.TASK_ID;

Answer 2

Doing the EXPLAIN should shed some light on it.
You might see a performance gain by doing the table joins explicitly in the FROM clause instead of inside the WHERE (https://dev.mysql.com/doc/refman/5.7/en/join.html). By doing explicit joins (e.g. LEFT OUTER, etc...) you will not only improve the readability of the query, but may be able to use less expensive joins where needed. This also affects how the query is executed as each clause is executed in a specific order (MySQL query / clause execution order).