MySQL is frequently referred to as a database for Web applications. Partially it is really so, because MySQL became popular owing to its simplicity, high speed, and bounding with PHP. Developers of small Web projects often choose MySQL as a back end of their sites. Does this mean that MySQL can be used only for small databases? Not at all. There are lots of databases size of data in which is measured in gigabytes. Besides MySQL servers are frequently clustered to increase their performance. When a DBAs work with large amounts of data, they frequently have to make backup copies correctly and effectively, i. e. to export MySQL databases to SQL (or MySQL backup). It is extremely important to import MySQL database from SQL correctly is when restoring a corrupted database and when migrating a database from one server to another.

What should be taken into account when exporting a large MySQL …

There are several ways to take backups (some good, some bad, and some will depend on your situation). Here's the thought process I use for choosing a backup strategy.

1. 
   
2. mysqldump
   If your data set is small (I realize "small" is a relative term.. to qualify it, let's say

• backup everything or just certain databases or tables
  
• backup only the DDL
  
• optimize the dump for a faster restore
  
• make the resultant sql file more compatible with other RDBMSes
  and many more things.
  

However, the most important options are related to the consistency of your backup. My favorite options are:

• --single-transaction : this option gives a consistent backup, if (and only if) the tables are using InnoDB storage engine. If you have any non-read-only MyISAM tables, then don't use this …

The Malta MySQL User Group (MMUG) met for the second time this Thursday, and compared to last time, we had a much better venue: Ixaris Systems let us use their board room, so we had all the tools we needed to have a good meeting.

We managed to get a group picture before everyone has arrived, so I guess we can call the people in this picture “early birds”.

Once we all arrived, however, Sandro Gauci from EnableSecurity gave us a very interesting talk on SQL Injection security, and general security flaws from a developer point a view. You can find the slides here: sql-injection.pdf.

Here’s a picture of Mr. Gauci while presenting. (Sorry for the obvious problem with the over-white picture — seems like I …

I need help from my fellow mysql users.  I know some of the people who read this are alot better then me with mysql so hopefully you can help

So today we decided that we are going to migrate one of our master database servers to new hardware.  Since we got the hardware this morning and we wanted to move on to it asap, we decided that we will take our slave down, copy data from it, and bring it up on future master server.  At that point, we will let it run as slave to the current master server until its time for us to take it down.  Reason we did that instead of mysqldump/import was to avoid the lag mysqldump creates on our server.

After we did all this and put up the new master server, we started to notice odd issues.  After looking around and comparing old db with new, we found out that new db was missing data.  How it happened is beyond me and is the reason why I am writing this.  …

Before we go into how to set up master-slave replication in MySQL, let us talk about some of the reasons I have set up master-slave replication using MySQL. 1) Offload some of the queries from one server to another and spread the load: One of the biggest advantages to have master-slave set [...] …

After I wrote the post: How do I dump all tables in a database into separate files? I got emails from couple people asking how to import the individual table files back in to MySQL. First way to import each sql file created by the post is to import each file individually by [...] …

There have been numerous occasions where I needed to make backups of individual tables from selected database. Usually I can achieve this by typing: mysqldump database_name table1 > table1.sql mysqldump database_name table2 > table2.sql

This could be very painful if you have 10?s or 100?s of tables. Until today, I never ran into a situation where I [...] …

One of the mysql database servers I manage started to have issues with doing backups yesterday. mysqldump was running but nothing was happening on the backup side. I started to investigate to see why our full backups were failing. I opened up the mysql error log file (mine is at: /usr/local/mysql/var/hostname.err) [...] …

One very interesting thing I noticed with MySQL was that if you delete a database, ibdata file doesn’t shrink by that much space to minimize disk usage. I deleted the database and checked usage of /usr/local/mysql/var folder and noticed that ibdata file is still the same size. So the problem I face now [...]

In one of my previous posts: MySQL backups, I talked about using a script for automating backups. I show that we can use gzip to compress backup file to compress and save. Since then, our backup file has been growing meg or two a day which is causing our backup files to get [...]