Super Slow Query - sped up, but not perfect... Please help - sql

Question

I posted a query yesterday (see here) that was horrible (took over a minute to run, resulting in 18,215 records):
SELECT DISTINCT
dbo.contacts_link_emails.Email, dbo.contacts.ContactID, dbo.contacts.First AS ContactFirstName, dbo.contacts.Last AS ContactLastName, dbo.contacts.InstitutionID,
dbo.institutionswithzipcodesadditional.CountyID, dbo.institutionswithzipcodesadditional.StateID, dbo.institutionswithzipcodesadditional.DistrictID
FROM
dbo.contacts_def_jobfunctions AS contacts_def_jobfunctions_3
INNER JOIN
dbo.contacts
INNER JOIN
dbo.contacts_link_emails
ON dbo.contacts.ContactID = dbo.contacts_link_emails.ContactID
ON contacts_def_jobfunctions_3.JobID = dbo.contacts.JobTitle
INNER JOIN
dbo.institutionswithzipcodesadditional
ON dbo.contacts.InstitutionID = dbo.institutionswithzipcodesadditional.InstitutionID
LEFT OUTER JOIN
dbo.contacts_def_jobfunctions
INNER JOIN
dbo.contacts_link_jobfunctions
ON dbo.contacts_def_jobfunctions.JobID = dbo.contacts_link_jobfunctions.JobID
ON dbo.contacts.ContactID = dbo.contacts_link_jobfunctions.ContactID
WHERE
(dbo.contacts.JobTitle IN
(SELECT JobID
FROM dbo.contacts_def_jobfunctions AS contacts_def_jobfunctions_1
WHERE (ParentJobID <> '1841')))
AND
(dbo.contacts_link_emails.Email NOT IN
(SELECT EmailAddress
FROM dbo.newsletterremovelist))
OR
(dbo.contacts_link_jobfunctions.JobID IN
(SELECT JobID
FROM dbo.contacts_def_jobfunctions AS contacts_def_jobfunctions_2
WHERE (ParentJobID <> '1841')))
AND
(dbo.contacts_link_emails.Email NOT IN
(SELECT EmailAddress
FROM dbo.newsletterremovelist AS newsletterremovelist))
ORDER BY EMAIL
With a lot of coaching and research, I've tuned it up to the following:
SELECT contacts.ContactID,
contacts.InstitutionID,
contacts.First,
contacts.Last,
institutionswithzipcodesadditional.CountyID,
institutionswithzipcodesadditional.StateID,
institutionswithzipcodesadditional.DistrictID
FROM contacts
INNER JOIN contacts_link_emails ON
contacts.ContactID = contacts_link_emails.ContactID
INNER JOIN institutionswithzipcodesadditional ON
contacts.InstitutionID = institutionswithzipcodesadditional.InstitutionID
WHERE
(contacts.ContactID IN
(SELECT contacts_2.ContactID
FROM contacts AS contacts_2
INNER JOIN contacts_link_emails AS contacts_link_emails_2 ON
contacts_2.ContactID = contacts_link_emails_2.ContactID
LEFT OUTER JOIN contacts_def_jobfunctions ON
contacts_2.JobTitle = contacts_def_jobfunctions.JobID
RIGHT OUTER JOIN newsletterremovelist ON
contacts_link_emails_2.Email = newsletterremovelist.EmailAddress
WHERE (contacts_def_jobfunctions.ParentJobID <> 1841)
GROUP BY contacts_2.ContactID
UNION
SELECT contacts_1.ContactID
FROM contacts_link_jobfunctions
INNER JOIN contacts_def_jobfunctions AS contacts_def_jobfunctions_1 ON
contacts_link_jobfunctions.JobID = contacts_def_jobfunctions_1.JobID
AND contacts_def_jobfunctions_1.ParentJobID <> 1841
INNER JOIN contacts AS contacts_1 ON
contacts_link_jobfunctions.ContactID = contacts_1.ContactID
INNER JOIN contacts_link_emails AS contacts_link_emails_1 ON
contacts_link_emails_1.ContactID = contacts_1.ContactID
LEFT OUTER JOIN newsletterremovelist AS newsletterremovelist_1 ON
contacts_link_emails_1.Email = newsletterremovelist_1.EmailAddress
GROUP BY contacts_1.ContactID))
While this query is now super fast (about 3 seconds), I've blown part of the logic somewhere - it only returns 14,863 rows (instead of the 18,215 rows that I believe is accurate).
The results seem near correct. I'm working to discover what data might be missing in the result set.
Can you please coach me through whatever I've done wrong here?
Thanks,
Russell Schutte

Answer 1

The main problem with your original query was that you had two extra joins just to introduce duplicates and then a DISTINCT to get rid of them.
Use this:
SELECT cle.Email,
c.ContactID,
c.First AS ContactFirstName,
c.Last AS ContactLastName,
c.InstitutionID,
izip.CountyID,
izip.StateID,
izip.DistrictID
FROM dbo.contacts c
INNER JOIN
dbo.institutionswithzipcodesadditional izip
ON izip.InstitutionID = c.InstitutionID
INNER JOIN
dbo.contacts_link_emails cle
ON cle.ContactID = c.ContactID
WHERE cle.Email NOT IN
(
SELECT EmailAddress
FROM dbo.newsletterremovelist
)
AND EXISTS
(
SELECT NULL
FROM dbo.contacts_def_jobfunctions cdj
WHERE cdj.JobId = c.JobTitle
AND cdj.ParentJobId <> '1841'
UNION ALL
SELECT NULL
FROM dbo.contacts_link_jobfunctions clj
JOIN dbo.contacts_def_jobfunctions cdj
ON cdj.JobID = clj.JobID
WHERE clj.ContactID = c.ContactID
AND cdj.ParentJobId <> '1841'
)
ORDER BY
email
Create the following indexes:
newsletterremovelist (EmailAddress)
contacts_link_jobfunctions (ContactID, JobID)
contacts_def_jobfunctions (JobID)

Answer 2

Do you get the same results when you do:
SELECT count(*)
FROM
dbo.contacts_def_jobfunctions AS contacts_def_jobfunctions_3
INNER JOIN
dbo.contacts
INNER JOIN
dbo.contacts_link_emails
ON dbo.contacts.ContactID = dbo.contacts_link_emails.ContactID
ON contacts_def_jobfunctions_3.JobID = dbo.contacts.JobTitle
SELECT COUNT(*)
FROM
contacts
INNER JOIN contacts_link_jobfunctions
ON contacts.ContactID = contacts_link_jobfunctions.ContactID
INNER JOIN contacts_link_emails
ON contacts.ContactID = contacts_link_emails.ContactID
If so keep adding each join conditon on until you don't get the same results and you will see where your mistake was. If all the joins are the same, then look at the where clauses. But I will be surprised if it isn't in the first join because the syntax you have orginally won't even work on SQL Server and it is pretty nonstandard SQL and may have been incorrect all along but no one knew.
Alternatively, pick a few of the records that are returned in the orginal but not the revised. Track them through the tables one at a time to see if you can find why the second query filters them out.

Answer 3

I'm not directly sure what is wrong, but when I run in to this situation, the first thing I do is start removing variables.
So, comment out the where clause. How many rows are returned?
If you get back the 11,604 rows then you've isolated the problems to the joins. Work though the joins, commenting each one out (remove the associated columns too) and figure out how many rows are eliminated.
As you do this, aim to find what is causing the desired rows to be eliminated. Once isolated, consider the join differences between the first query and the second query.
In looking at the first query, you could probably just modify that to eliminate any INs and instead do a EXISTS instead.
Consider your indexes as well. Any thing in the where or join clauses should probably be indexed.