An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.
3
votes
2answers
853 views
“freeing items” taking forever on inserts, updates and deletes
Recently I migrated all my MySQL database tables from MyISAM engine to InnoDB. I'm using the DotCloud MySQL service as my server (http://docs.dotcloud.com/services/mysql/).
After the migration, ...
1
vote
2answers
60 views
Linked Server Risks
I'm implementing a new feature which requires data from databases on multiple servers. I just need to union data from all these servers and sort it. The two options that come to mind are:
Use linked ...
1
vote
2answers
81 views
sql server 2008 execution plan different on two production servers
We have two servers running SQL server 2008 R2, with identical databases, where we implemented a datawarehousing solution. The cube processing operation was taking a VERY long time in one of the ...
1
vote
2answers
218 views
SELECTing multiple columns through a subquery
I am trying to SELECT 2 columns from the subquery in the following query, but unable to do so. Tried creating alias table, but still couldn't get them.
SELECT DISTINCT petid, userid,
(SELECT ...
1
vote
2answers
343 views
Mysql innoDB write operations are extremely slow
I'm having serious performance problems with MySQL and the InnoDB engine. Even the simplest table makes writing operations (creating the table, inserting, updating and deleting) horribly slow, as you ...
0
votes
2answers
46 views
How do I use subquery on the same table in MySQL?
I have a query like this which takes a really long time to run. The table is around 4 million rows.
DELETE FROM TABLE WHERE value_was IS NULL OR value_was <= value_now;
I'm hoping I could ...
0
votes
2answers
36 views
Is there slowdown inserting into an InnoDB table that has no index set?
I have an old application with lots of InnoDB tables, that have no indexes at all, not even a primary ID or such.
Those tables only contain a few thousand rows.
Would it be faster to INSERT data ...
0
votes
2answers
67 views
Multiple database servers for performance vs failover
If I have two database servers, and I am looking for maximum performance vs high-availability, what configuration would be best?
Assuming the architecture is two load-balanced web/app servers in ...
0
votes
2answers
40 views
How to modify MySQL 5.5 settings that were set during the installation?
Especially the one that defines how MySQL is gonna use server's CPU. I'd like to boost performance. Also, what are other ways to boost MySQL performance? (Maybe some code optimization hints?) Anyway. ...
1
vote
1answer
277 views
MySQL performance tuning + queries stuck on “Copying to tmp table”
The latter part of the question's title (queries stuck on "Copying to tmp table") has been addressed many times, and I have spent a fair amount of time researching this. I would appreciate it if you ...
1
vote
1answer
51 views
tuning feed item's table query with multiple condition
I have a query like this:
SELECT *
FROM `rss_item`
WHERE `feed_id` = 1 and `timestamp` < 1350698635
ORDER BY `rss_item`.`timestamp` ASC
MySQL: 5.1; table engine: innodb
Explain result:
...
1
vote
1answer
100 views
Deriving formulas for input/output
I'm currently enrolled in a DBS class and am having problem with an assignment. I've searched around and have been unable to understand what it is I'm meant to be doing with this derivation formula.
...
0
votes
1answer
33 views
Having too many connection problem
We have an magento store and having 9K products and 2 store views the trouble is we are getting too many conection error while the site is in normal loads.
1) We have 100 connectoin open in mysql.
2) ...
0
votes
1answer
41 views
MySQL DB Design
I am designing a db for a Social Network type website where users enter lot of information varying from family member details, education, employment, personal favorite such as TV, movie, music, food, ...
0
votes
1answer
48 views
Efficient way to perform approximated search?
I have to perform a join between table_a and table_b, using three fields as key being one of them the date of the event, say, both tables have id1, id2 and evnt_time for eache record.
As it happens ...
0
votes
1answer
51 views
Cannot Utilize Maximum CPU and Memory Usage for MySQL
Good day.
I know this may be a duplicate of other questions however I have applied all the suggestions in many of the threads, but I remain with the same problem.
I have a single stored procedure ...
0
votes
1answer
68 views
Mysql. Block/disconnect slow queries
I am experiencing issue.
Someone 'attacked' my server: simply by searching the same phrase with multiple requests.
As it is text search request and database indices are not used, the engine searches ...
-1
votes
1answer
104 views
Tutorial in performance tuning
Where can I find about tutorial of performance tuning in SQL server 2012 or 2008 R2?
The purpose is to improve my knowledge in performance tuning.
