Export a large MySQL table as multiple smaller files

Question

I have a very large MySQL table on my local dev server: over 8 million rows of data. I loaded the table successfully using LOAD DATA INFILE.

I now wish to export thi

Answer 1

I just did an import/export of a (partitioned) table with 50 millions record, it needed just 2 minutes to export it from a reasonably fast machine and 15 minutes to import it on my slower desktop. There was no need to split the file.

mysqldump is your friend, and knowing that you have a lot of data it's better to compress it

 @host1:~ $ mysqldump -u <username> -p <database> <table> | gzip > output.sql.gz
 @host1:~ $ scp output.sql.gz host2:~/
 @host1:~ $ rm output.sql.gz
 @host1:~ $ ssh host2
 @host2:~ $ gunzip < output.sql.gz | mysql -u <username> -p <database>
 @host2:~ $ rm output.sql.gz

Answer 2

I found that the advanced options in phpMyAdmin allow me to select how many rows to export, plus the start point. This allows me to create as many dump files as required to get the table onto the remote host.

I had to adjust my php.ini settings, plus the phpMyAdmin config 'ExecTimeLimit' setting as generating the dump files takes some time (500,000 rows in each).

I use HeidiSQL to do the imports.

Answer 3

Use mysqldump to dump the table into a file. Then use tar with -z option to zip the file. Transfer it to your remote server (with ftp, sftp or other file transfer utility). Then untar the file on remote server Use mysql to import the file.

There is no reason to split the original file or to export in multiple files.

Answer 4

How do I split a large MySQL backup file into multiple files?

You can use mysql_export_explode https://github.com/barinascode/mysql-export-explode

<?php 
#Including the class

include 'mysql_export_explode.php';
$export = new mysql_export_explode;

$export->db = 'dataBaseName'; # -- Set your database name
$export->connect('host','user','password'); # -- Connecting to database
$export->rows = array('Id','firstName','Telephone','Address'); # -- Set which fields you want to export
$export->exportTable('myTableName',15); # -- Table name and in few fractions you want to split the table
?>

At the end of the SQL files are created in the directory where the script is executed in the following format
---------------------------------------
myTableName_0.sql
myTableName_1.sql
myTableName_2.sql
...

Answer 5

If you are not comfortable with using the mysqldump command line tool, here are two GUI tools that can help you with that problem, although you have to be able to upload them to the server via FTP!

Adminer is a slim and very efficient DB Manager tool that is at least as powerful as PHPMyAdmin and has only ONE SINGLE FILE that has to be uploaded to the server which makes it extremely easy to install. It works way better with large tables / DB than PMA does.

MySQLDumper is a tool developed especially to export / import large tables / DBs so it will have no problem with the situation you describe. The only dowside is that it is a bit more tedious to install as there are more files and folders (~350 files in ~1.5MB), but it shouldn't be a problem to upload it via FTP either, and it will definately get the job done :)

So my advice would be to first try Adminer and if that one also fails go the MySQLDumper route.

Answer 6

Take a look at mysqldump

Your lines should be (from terminal):

export to backupfile.sql from db_name in your mysql:

mysqldump -u user -p db_name > backupfile.sql

import from backupfile to db_name in your mysql:

mysql -u user -p db_name < backupfile.sql

You have two options in order to split the information:

1. Split the output text file into smaller files (as many as you need, many tools to do this, e.g. split).

2. Export one table each time using the option to add a table name after the db_name, like so:

   mysqldump -u user -p db_name table_name > backupfile_table_name.sql

Compressing the file(s) (a text file) is very efficient and can minimize it to about 20%-30% of it's original size.

Copying the files to remote servers should be done with scp (secure copy) and interaction should take place with ssh (usually).

Good luck.