MySQL queries - how expensive are they really?

Posted by incrediman on Stack Overflow See other posts from Stack Overflow or by incrediman
Published on 2010-03-18T11:57:56Z Indexed on 2010/03/18 12:01 UTC
Read the original article Hit count: 540

Filed under:

php

|

mysql

|

mysql-query

|

cost

|

optimization

I've heard that mysql queries are very expensive, and that you should avoid at all costs making too many of them.

I'm developing a site that will be used by quite a few people, and I'm wondering:

How expensive are mysql queries actually? If I have 400,000 people in my database, how expensive is it to query it for one of them?

How close attention do I need to pay that I don't make too many queries per client request?

© Stack Overflow or respective owner

Related posts about php

Magento, NGINX, PHP-FPM, APC, MEMCACHED, 16gb Ram CentOS, Spiking PHP-FPM to 100% CPU

as seen on Server Fault - Search for 'Server Fault'
I have been trying to resolve my issue of spiking cpu caused by php-fpm processes. I've reduced the php-fpm config settings to: pm = ondemand pm.max_children = 12 pm.start_servers = 2 pm.min_spare_servers = 2 pm.max_spare_servers = 10 pm.max_requests = 500 php_admin_value[memory_limit] = 128M Problem… >>> More
PHP Pear Installation on CentOS

as seen on Server Fault - Search for 'Server Fault'
[root@ip ~]# yum install php-pear* Reducing CentOS-5 Testing to included packages only Finished Setting up Install Process Package 1:php-pear-1.8.1-2.el5.centos.noarch already installed and latest versio … >>> More
Apache configurations for php "AddType text/html php" or "AddType application/x-httpd-php php .php"

as seen on Server Fault - Search for 'Server Fault'
I am taking over an application server and discover that it contain the following settings: AddType text/html php Although it works, but my understanding is that it should set as following: AddType application/x-httpd-php php .php What are the key differences between the two settings?… >>> More
mod_rewrite settings causes server to throw HTTP 500 errors instead of 404

as seen on Server Fault - Search for 'Server Fault'
Hello. I have a server with VBulletin forum (working under Apache 2.2, CentOS). The default settings for it in .htaccess are as follows: RewriteEngine on RewriteCond %{HTTP_HOST} ^gsmforum\.ru RewriteRule (.*) http://www.gsmforum.ru/$1 [R=301,L] # If you are having problems or are using VirtualDocumentRoot… >>> More
Problems installing Memcache (PECL extension)

as seen on Server Fault - Search for 'Server Fault'
I have installed memcached fine, and now I will need to install PECL extension memcache. Im running RedHat x86_64 es5. The installation gives me this: downloading memcache-2.2.6.tgz ... Starting to download memcache-2.2.6.tgz (35,957 bytes) ..........done: 35,957 bytes 11 source files, building running:… >>> More

Related posts about mysql

How to remove MySQL completely with config and library files on ubuntu 12.04 gnome 3.0

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried everything till now: sudo apt-get remove mysql-server mysql-client mysql-common sudo apt-get purge mysql-server mysql-client mysql-common sudo apt-get autoremove and even more commands... But whenever I am trying to locate mysql. I get a no. of files related to mysql command: shell>>… >>> More
mysql: Cannot load from mysql.proc. The table is probably corrupted

as seen on Server Fault - Search for 'Server Fault'
Mysql was started: /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 but when I'm trying to do something: ERROR 1548 (HY000) at line 1: Cannot… >>> More
Why is there a /etc/init.d/mysql file on this Slackware machine? How could it have gotten there?

as seen on Server Fault - Search for 'Server Fault'
A client of my IT-consulting service owns a web-development shop. He's been having problems with a Slackware 12.0 server running MySQL 5.0.67. The machine was set up by the client's sysadmin, who left on bad terms. My client no longer employs a sysadmin. As far as I can tell, the only copy of MySQL… >>> More
mysql: Bind on unix socket: Permission denied

as seen on Server Fault - Search for 'Server Fault'
Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases… >>> More
MySQL – Learning MySQL Online in 6 Hours – MySQL Fundamentals in 320 Minutes

as seen on SQL Authority - Search for 'SQL Authority'
MySQL is one of the most popular database language and I have been recently working with it a lot. Data have no barrier and every database have their own place. I have been working with MySQL for quite a while and just like SQL Server, I often find lots of people asking me if I have a tutorial which… >>> More