Questions about database performance and tuning, ranging from files organization and configuration to benchmarking and system optimization, passing through management systems and the fastest ways to operate a database.
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1answer
18 views
How to tune self-join table in mysql like this?
I have this table which I'm trying to select from and to date. The query took 2 min to run on 4 million records. I'm not sure how much more I can squeeze out of this query.
SELECT c.fk_id, ...
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3answers
55 views
Avoiding multiple calculation for the same values
Is there a way that I can improve the performance of this query by avoiding multiple calculation of some repeating values like
regexp_replace(my_source_file, ...
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votes
1answer
38 views
Postgres two subqueries poor performance [EAV model]
I have a table called "meta" with 2.2 million records. This table contains 3 columns: productId, key and value. Key and value are the two columns containing a meta description of a product.
The ...
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votes
2answers
40 views
Working with big amount of data. PHP Sessions or accessing data every time?
We have this web app we're working on where users store some bookmarks (url/title/shortkey/times url clicked) etc.
Every time the user refreshes the page, this data is being retrieved from the ...
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0answers
26 views
Linq To Sql Category Sub Category Count Performans
Product Table : ID Name ...
Category Table : ID ParentCategoryID Name
ProductCategories Table : ID CatID ProdID
and.. ProductCategories in CatID foreign key and ProdID foreign key
multiple SQL ...
1
vote
1answer
28 views
When is it better to flatten out data using comma separated values to improve search query performance?
My question about SEARCH query performance.
I've flattened out data into a read-only Person table (MySQL) that exists purely for search. The table has about 20 columns of data (mostly limited text ...
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0answers
8 views
What is the total number of open connections recommended for HTML5 websql database?
My target browser is chrome and opera latest versions. Please let me know if there has been any study done on how many (max size) open connections (open simultaneously) on HTML5 websql database is ...
1
vote
1answer
58 views
When is the right time to create Indexes in Oracle?
A brand new application with Oracle as DataStore is going to be pushed in Production. The Databases use CBO and I have indentified some columns to do indexing. I am expecting the total number of ...
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0answers
7 views
Joomla 1.5.10 serious performance issues?
We have build a Intranet on Joomla, its used by more than 20,000 users. At times there are 200 or more concurrent users on the site. And site starts working slow and sometimes crashes. What should we ...
0
votes
1answer
43 views
Am I doing indexes for my MySQL table right?
I have a MySQL table that has a list of messages, where each message belongs to a room. I do queries like this:
SELECT * FROM messages WHERE room='offtopic' ORDER BY id DESC LIMIT 5;
As my table ...
2
votes
3answers
32 views
Sorting records quickly from a model with 500k records
I am attempting to sort records in a model which has 500k rows in it. When I initially attempted this procedure I had just 200 records and used the following code and pulled out records 1-5 to list ...
1
vote
2answers
28 views
Multiple SQL queries checking against 1 row vs 1 single query checking against multiple rows
I am curious, what has a better performance. A little bit about the context : I am processing a CSV file that needs to be entered into a database table and need to ensure that I smell out the ...
2
votes
2answers
54 views
Dropping unnecessary indexes - effect on query plans in SQL Server 2005
Below is a portion of the index mess we have on a 2MM record table (SQL Server 2005). Clearly there are opportunities to pear them down. This table has 16 indexes altogether, including a clustered PK ...
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votes
2answers
33 views
Caching Data on a Heavy Load Web Server
I currently have a web application which on each page request gets user data out of a database, for the currently logged in user.
This web application could have approximately 30 thousands concurrent ...
1
vote
1answer
32 views
Benefits of using mediumint instead of int for primary key columns?
I inherited a database where the previous developer used a mix of mediumint and int for key columns. I am now going through the database and trying to add foreign keys and I have run into some ...
