MySQL ALTER TABLE on very large table - is it safe to run it?

Posted by Timothy Mifsud on Stack Overflow See other posts from Stack Overflow or by Timothy Mifsud
Published on 2009-08-31T19:47:55Z Indexed on 2010/04/12 23:43 UTC
Read the original article Hit count: 257

Filed under:

mysql

|

alter

|

table

|

large

|

primary-key

I have a MySQL database with one particular MyISAM table of above 4 million rows. I update this table about once a week with about 2000 new rows. After updating, I then perform the following statement:

ALTER TABLE x ORDER BY PK DESC

i.e. I order the table in question by the primary key field in descending order. This has not given me any problems on my development machine (Windows with 3GB memory), but, even though 3 times I have tried it successfully on the production Linux server (with 512MB RAM - and achieving the resulted sorted table in about 6 minutes each time), the last time I tried it I had to stop the query after about 30 minutes and rebuild the database from a backup.

I have started to wonder whether a 512MB server can cope with that statement (on such a large table) as I have read that a temporary table is created to perform the ALTER TABLE command?! And, if it can be safely run, what should be the expected time for the alteration of the table?

Thanks in advance, Tim

© Stack Overflow or respective owner

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

Related posts about alter

Convert VARCHAR() columns to NVARCHAR()

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
We recently underwent an upgrade that required us to change our database columns from varchar to NVarchar, to support unicode characters. Digging through the internet, I found a base script which I modified to handle reserved word table names, and maintain the NULL/NotNull constraint of the columns… >>> More
query " ALTER TABLE test_posts ADD sticky boolean NOT NULL default = false" = error

as seen on Stack Overflow - Search for 'Stack Overflow'
Whats wrong with my query? ALTER TABLE test_posts ADD sticky boolean NOT NULL default = false #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '=false' at line 2 >>> More
Create user in Oracle 11g with same priviledges as in Oracle 10g XE

as seen on Server Fault - Search for 'Server Fault'
I'm a PHP developer (not a DBA) and I've been working with Oracle 10g XE for a while. I'm used to XE's simplified user management: Go to Administration/ Users/ Create user Assign user name and password Roles: leave the default ones (connect and resource) Privileges: click on "Enable all" to select… >>> More
One of my most frequently used commands

as seen on Oracle Blogs - Search for 'Oracle Blogs'
On a Linux or UNIX server this is one of my most frequently used commands. find . -name "*.htm" -exec grep -iH "alter session" {} \; It is an easy way to find a string you know is in a group of files, but don't know or can't remember which file it is in. For the example… >>> More
SQL Server script commands to check if object exists and drop it

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
Over the past couple years I’ve been keeping track of common SQL Server script commands that I use so I don’t have to constantly Google them. Most of them are how to check if a SQL object exists before dropping it. I thought others might find these useful to have them all in one place, so… >>> More