The query optimizer is the component of a database management system that attempts to determine the most efficient way to execute a query.
2
votes
1answer
932 views
Mysql Memory table getting many locks
On my site I log every pageview (date, ip, referrer, page, etc) in a simple mysql table.
This table has the following activity:
1 SELECT per minute
1 DELETE per minute
no UPDATE queries
Lots of ...
23
votes
3answers
2k views
Unexpected scans during delete operation using WHERE IN
I've got a query like the following:
DELETE FROM tblFEStatsBrowsers WHERE BrowserID NOT IN (
SELECT DISTINCT BrowserID FROM tblFEStatsPaperHits WITH (NOLOCK) WHERE BrowserID IS NOT NULL
)
...
7
votes
3answers
281 views
Why are there execution plan differences between OFFSET … FETCH and the old-style ROW_NUMBER scheme?
The new OFFSET ... FETCH model introduces with SQL Server 2012 offers simple and faster paging. Why are there any differences at all considering that the two forms are semantically identical and very ...
4
votes
2answers
542 views
Is there a way to hint to query optimizer to MySQL which constraints should be done first?
This is my current query:
SELECT BusinessID as ID,
111151.29341326*SQRT(pow(-6.186751-X(LatLong),2)+pow(106.772835-Y(LatLong),2)*0.98838574205337) AS Distance from
(
SELECT *
FROM
...
1
vote
1answer
241 views
MySQL optimization
I'm trying to optimize a MySQL Server to be able to serve as many connections as it can.
The server is in AmazonAWS RDS and has currently the following resources:
--7.5 GB memory, 4 ECUs (2 ...
