In the context of a database, optimisation refers to the process of the query optimiser selecting the best query plan to execute.
2
votes
3answers
499 views
MySQL optimization - year column grouping - using temporary table, filesort
I have a transactions table which is having 600,000 records, I need to list the count for the dashboard on financial year basis. The table used is MyISAM. I tried adding index for the transaction date ...
2
votes
2answers
82 views
How to optimize a log process in MySQL?
In my project, I have about 100.000 users and can't control their behavior. Now, what I would like to do is log their activity in a certain task. Every activity, is one record which includes columns ...
1
vote
2answers
266 views
Slow insert with MySQL full-text index
I use a full-text index in a MySQL table, and each insert into this table takes about 3 seconds. It seems that MySQL rebuilds (a part) of the full text index after each insert/update. Is this right?
...
0
votes
2answers
170 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 ...
2
votes
1answer
47 views
Optimize UNION query in MYSQL
I have a problem with a UNION query in MySQL. We have 10 millions players on our website and we would like to select players with a multi-criterias system. For exemple, selecting US people, men, > 35 ...
2
votes
1answer
95 views
mysql: need help to optimize my query/table
I'm wondering if someone could help me optimize my tables/query to speed up a query. It is currently running ridiculously slow. I think a well-thought out index could help me. Any help would be really ...
0
votes
1answer
52 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 ...
0
votes
1answer
70 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
1answer
77 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 ...
2
votes
0answers
86 views
How can row estimates be improved in order to reduce chances of spills to tempdb
I notice that when there are spill to tempdb events (causing slow queries) that often the row estimates are way off for a particular join. I've seen spill events occur with merge and hash joins and ...
2
votes
0answers
161 views
MySQL: Improve performance for one row insert into table with unique constraint
I have a table with ~ 40 mil records, with a unique index on the url collumn, of type varchar(255).
Now the insert speed is about 30/s, is this expected? how could I improve it?
I can't use bulk ...
2
votes
0answers
69 views
Optimizations for new SQL Server 2000 database that will act as email queue AND API database
Due to limitations put on me I've got to put my outgoing Email Queue in the same database as my customer information.
What are some optimizations I can make, specifically to the Email portion that ...
1
vote
0answers
92 views
How can I join one to one to (many to one) without using group_concat
I have a table structure as follows:
--
-- Table structure for table `emails`
--
CREATE TABLE IF NOT EXISTS `emails` (
`ID` int(5) NOT NULL AUTO_INCREMENT,
`email` varchar(255) COLLATE ...
1
vote
0answers
164 views
Finding the bottleneck by analyzing Munin graphs
We’ve been experiencing some issues with our database server during peak hours. In our Nginx error-log we can see that a lot of requests get timed out. The requests are also very slow. We have had ...
1
vote
0answers
538 views
SQL query optimization in Prestashop e-Commerce solution
I'm working on a layered navigation module within Prestashop e-Commerce solution.
I'm trying to optimize a SQL query which creates a temp table during execution. I think this is creating a ...
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0answers
36 views
Using something better than UNION for combining multiple queries
I have one big query which is based on 12 smaller queries that I have put together using UNION.
A relative simple example of my query:
(SELECT
'type1' AS 'type',
fieldOne AS someField,
...
0
votes
0answers
72 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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votes
0answers
22 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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0answers
78 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), ...
0
votes
0answers
119 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 ...
0
votes
0answers
48 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 ...
0
votes
0answers
91 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 ...
0
votes
0answers
673 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 ...
