Difference between revisions of "Mysqldump"

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When using MySQL, I always use a .my.cnf file to store my password so that I can switch to 'root' on the host, and execute whatever commands I need.
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quick recipe on using mysqldump
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<source lang="bash">
 
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file=~/.my.cnf
 
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touch $file
 
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chmod 600 $file
 
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cat <<EOF >> $file
 
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[client]
 
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user=root
 
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password=SuperSecretSauce
 
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EOF
 
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</source>
 
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== Backup Script ==
 
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Here's a quick recipe using <code>mysqldump</code>
 
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== Backup ==
 
<code>cat ./backup.db.sh</code>
 
<code>cat ./backup.db.sh</code>
 
<source lang="bash">
 
<source lang="bash">
 
#!/bin/sh
 
#!/bin/sh
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# @author Greg Rundlett <info@eQuality-Tech.com>
 
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# This is a quick shell script to create a sql dump of your database.
 
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# You may need to adjust the path of mysqldump,
 
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# or sudo apt-get install mysqldump  if it doesn't exist
 
  
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# We'll make it so you can pass the database name as the first parameter
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DB=wiki
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# to the script for playbook / cron / non-interactive use
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backupdir="$HOME/backups";
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# If no parameter is passed, we'll prompt you for the name
 
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DB=$1
 
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if [ $# -ne 1 ]; then
 
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  echo "Here are the current databases on the server"
 
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  mysql -u root --batch --skip-column-names -e 'show databases;'
 
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  echo "Enter the name of the database you want to backup"
 
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  read DB
 
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fi
 
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# If on a Virtual Machine, use a location that is exported to the host,
 
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# so that our backups are accessible even if the virtual machine is no longer accessible.
 
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# backupdir="/vagrant/mediawiki/backups";
 
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backupdir="/backups";
 
 
if [ ! -d "$backupdir" ]; then
 
if [ ! -d "$backupdir" ]; then
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   mkdir -p "$backupdir";
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   mkdir -p $backupdir;
 
fi
 
fi
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backup="$backupdir/dump-$(date +%F).$(hostname)-$DB.sql";
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# shell parameter expansion
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# increment the filename if it already exists
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# see http://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
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# http://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html#Shell-Parameter-Expansion
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# we'll start with a default backup file named '01' in the sequence
 
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backup="${backupdir}/dump-$(date +%F).$(hostname)-${DB}.01.sql";
 
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# and we'll increment the counter in the filename if it already exists
 
 
i=1
 
i=1
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filename=$(basename "$backup") # foo.txt (basename is everything after the last slash)
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filename=$(basename "$backup") # foo.txt
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extension=${filename##*.}             # .txt (filename with the longest matching pattern of *. being deleted)
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extension=${filename##*.}     # .txt
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file=${filename%.*}                         # foo (filename with the shortest matching pattern of .* deleted)
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file=${filename%.*}           # foo
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file=${file%.*}                                  # repeat the strip to get rid of the counter
 
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# file=${filename%.{00..99}.$extension} # foo (filename with the shortest matching pattern of .[01-99].* deleted)
 
 
while [ -f $backup ]; do
 
while [ -f $backup ]; do
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   backup="$backupdir/${file}.$(printf '%.2d' $(( i+1 ))).${extension}"
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   backup="$backupdir/${file}.${i}.${extension}"
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   i=$(( i+1 )) # increments $i  
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   i=$(( i+1 ))   # increments $i
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  # note that i is naked because $(( expression )) is arithmetic expansion in bash
 
 
done
 
done
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if /usr/bin/mysqldump --single-transaction "$DB" > "$backup"; then
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/usr/bin/mysqldump $DB > $backup;
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  echo "backup created successfully"
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ls -al $backup;
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  ls -al "$backup";
 
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  echo "A command such as"
 
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  echo "mysql -u root $DB < $backup"
 
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  echo "will restore the database from the chosen sql dump file"
 
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else
 
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  echo "ERROR: Something went wrong with the backup"
 
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  exit 1
 
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fi
 
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</source>
 
  
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== Backup One-liner ==
 
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For times when you need to enter a password
 
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<source lang="bash">
 
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db=MYDATABASE;
 
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mysqldump -u db_user $db -p > ./tmp/dump-$(date +%F).$(hostname)-$db.sql
 
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</source>
 
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For all databases on a host
 
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<source lang="bash">
 
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mysql --execute="show databases" | awk '{print $1}' | grep -iv ^Database$ | sed 's/\(.*\)/mysqldump --single-transaction \1 > \1.'$(date +"%Y%m%d")'.sql/'
 
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# Then just redo the command piped to sh
 
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</source>
 
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One of many ways to dump a database from one machine to another
 
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<source lang="bash">
 
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sudo mysqldump --single-transaction mydb | gzip -c | ssh ubuntu@10.0.50.53 'cat > /home/ubuntu/mydb.dump.sql.gz'
 
 
</source>
 
</source>
  
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<source lang="bash">
 
<source lang="bash">
 
mysql $DB < $backup
 
mysql $DB < $backup
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</source>
 
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Using process substitution and <code>zcat</code>, you don't even need to uncompress your gzipped backups first. 
 
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<source lang="bash">
 
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mysql -p -u db_user db < <(zcat ./scheduled/eQualityTechnology-2015-03-15T23-11-50.mysql.gz)
 
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</source>
 
</source>
  
 
[[Category:Database]]
 
[[Category:Database]]
 
[[Category:Bash]]
 
[[Category:Bash]]
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[[Category:System Administration]]
 

Revision as of 12:05, 11 December 2014

quick recipe on using mysqldump

Backup[edit | edit source]

cat ./backup.db.sh 

#!/bin/sh

DB=wiki
backupdir="$HOME/backups";
if [ ! -d "$backupdir" ]; then
  mkdir -p $backupdir;
fi
backup="$backupdir/dump-$(date +%F).$(hostname)-$DB.sql";
# increment the filename if it already exists
# http://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html#Shell-Parameter-Expansion
i=1
filename=$(basename "$backup") # foo.txt
extension=${filename##*.}      # .txt
file=${filename%.*}            # foo
while [ -f $backup ]; do
  backup="$backupdir/${file}.${i}.${extension}"
  i=$(( i+1 ))   # increments $i
done
/usr/bin/mysqldump $DB > $backup;
ls -al $backup;

Restore[edit | edit source]

mysql $DB < $backup
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