In the context of a database, optimisation refers to the process of the query optimiser selecting the best query plan to execute.
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Optimizing ORDER BY for simple MySQL query
I'm trying to optimize this really simple query, and it gives me grief for a day now :(
Seems pretty straightforward, I need to select with a JOIN from 2 tables, and get top X results sorted in a ...
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votes
1answer
42 views
Memcache implementation
I have a Wordpress site that uses WP Super Cache plugin in order to make my blog posts and pages stay as HTML so that less PHP/MySQL code is executed. However, there's a featured box that can't get ...
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2answers
74 views
Why does using a variable make a difference in performance?
I have a table that constantly doing insert, and I am trying to run a delete script to remove old record.
The delete script looks like this:
DECLARE @StarDate DATETIME = '2013-01-13';
DECLARE ...
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2answers
72 views
Exploring and optimizing SQL performance of your system (PostgreSQL and Hibernate)?
Imagine you have inherited some project with extensive usage of SQL queries.
Let us assume that Hibernate is used as ORM and PostgreSQL as database, but thats not the point.
A question is: could ...
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1answer
47 views
Faster joining on 'most recent' related rows
I have a bug tracking application. The bug table stores very little,
because every state change to a bug happens by adding a comment. For
example, the current state of a bug is determined by the state ...
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3answers
223 views
Mysql optimization help
I've tried optimizing mysql as good as I could, but apparently I'm not to good at it :-)
So I come to you guys for help.
Server specs are:
AMD Opteron CPU 8 cores
16 GB RAM
2x2.000 GB HDD 7.200 RPM ...
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1answer
757 views
Mysql 5.5: Optimizing all tables with mysqlcheck - is it useful to run the -check option along with -optimize?
I plan on running 'mysqlcheck --optimize --all-databases' to clear up some fragmentation.
Would it be useful to run -check with this option or does the -optimize already take care of that?
I am only ...
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1answer
103 views
MySQL query optimization
I'm quite new to big MySQL queries (I used to extract raw data from tables then manipulate them with PHP) so I'd like to know if my query below is too "heavy" or slow for some reason (it seems to be ...
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1answer
79 views
Why searching with $all in Mongodb is FAR SLOWER than the EQUIVALENT search?
$all with only one item is equivalent with normal search right?
Here is the log without $all (I used 4700 test cases with 30 thread):
Thu Sep 20 17:27:05 [conn11] query newisikotagte15.tablebusiness ...
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0answers
32 views
Are there any disadvantages to partitioning on financial year?
Our current set up has one table per financial year (May 1- April 30). Each table has approx 1.5 million rows. We have about 8 years of data, and will obviously be adding each year.
The majority of ...
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0answers
34 views
Optimising table efficiency format integers only [closed]
I currently have a table with 1,136,053 rows and 5 columns in a MySQL table.
They are all integer values and appear to be slowing down as I am increasing the rows.
I have indexed each of the ...
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0answers
65 views
InnoDB tuning with 1G of ram limit
I am trying to calculate variable moving averages crossover with variable dates.
That is: I want to prompt the user for 3 values and 1 option. The input is through a web front end so I can build/edit ...
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0answers
18 views
Table partionning problem
I need your help for a partionning problem. We are using a "log_event" table which log a lot of events sent by our players (subscription, connection, play, share, etc...). We insert 5,000 row / s in ...
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votes
1answer
60 views
Database schema design help needed
I am developing a PHP application expecting millions of records both parent and children. My goal is to design an optimized database design to achieve high speed and performance.
This application ...
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votes
2answers
194 views
MySQL tuning (my.cnf) for very large tables and ad hoc queries [duplicate]
We are an email marketing company and recently switched our setup to MySQL. We need to configure mysql (my.cnf) for extreme performance.
We have tried to configure my.cnf but heavy queries can get ...
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votes
1answer
101 views
MySQL subqueries that use range based on values of main queries don't use indices properly
I think I've isolated a problem that has been affecting many of my queries lately.
And would like some help to figure out a solution for this.
Ok so my findings are that a normal query that runs very ...
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votes
2answers
60 views
Academic Journals and Reviews for Database Systems [closed]
I want to start reading up on the latest advances in database technology. Can anyone tell me what are the leading academic journals on the subject?
Also, I have a friend doing a PhD in another area ...
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0answers
34 views
optimize this query [duplicate]
Possible Duplicate:
Slow query performance
My database contains 20,000 rows and the following query is slow. Please help me to speed this up.
SELECT r.report_id, ...
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0answers
71 views
What is faster - multiple access of table or using temporary table?
I have created two tables
create table one(ref_no int, name varchar(100), design varchar(100));
create table two(SNo int auto_increment primary key, use_date Date, ref_no int references one(ref_no), ...
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votes
1answer
124 views
Optimising MySQL query with lots of self-joins
I have an entity_relationship table that describes relationships between entities. Each relationship will have 2+ entities involved.
In some cases it can be said that one entity is a constituent of a ...
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votes
0answers
39 views
mysql select query optimization [duplicate]
Possible Duplicate:
mysql select query optimization
I have two tables, testa and testb.
CREATE TABLE `testa` (
`id` INT(10) NOT NULL AUTO_INCREMENT,
`name` VARCHAR(50) DEFAULT NULL,
...
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0answers
112 views
Which update is faster using join or sequential?
My this question is in sequence of my previous question I asked.
I could write two solutions using Stored Procedure instead of trigger or nested-query .
Both use a helper function ...
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votes
0answers
45 views
Load time implications of storing data in multiple rows vs serialized data
I am currently storing data in fields as shown below. Each of these pricing fields has two database rows associated with it, and there is up to 24 of these tables for a house. This therefore means ...
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votes
0answers
90 views
Optimization of an Oracle query
I have a view which is accessed via DBLink in Oracle. This view is made up of different tables. Now we have to execute queries on this view. Example:
Select * from Viewname@dblink where ...
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votes
0answers
649 views
Query alternates between fast and slow execution
We have an Oracle 11g2 installation. I have a query which joins four tables of approx. 30,000 rows each. The join conditions mostly are simple equalities. There are some NOT LIKE on strings and some ...
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0answers
457 views
PHp Mysql OPtimization using slow-log-query [closed]
Hi there i'm trying to fix a speed connection problem of my app located at:
sandbox.promls.net
try get access by:
david@vivarealty.com.mx
xxxxxx
you could se the sql statements on there
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votes
2answers
155 views
optimize big sql query
My query has to return a statistics for example for march containing productname and price and its sidedishes (1:n relation) with the right price of each sidedish and the right tax for each sidedish ...
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votes
2answers
61 views
strategies to get data from diff database [closed]
Problem
I have two databases user_works database and pricing database.
I want to take a join of two tables user_table which is in user_works database & rent_table which is in pricing database ...
-1
votes
1answer
73 views
Optimization of a select statement
I'm using MySQL and have a table user_data like this:
user_id int(10) unsigned
reg_date int(10) unsigned
carrier char(1)
The reg_data is the unix timestamp of the ...
-3
votes
0answers
31 views
Doubt :: my sql performance tuning [duplicate]
Possible Duplicate:
MySQL performance tuning
I would like to optimize my MySQL DB and I identified some important points as follows:
enabling query cache,
using memory storage (I know ...
