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dump all mysql tables into separate files automagically?

Posted by: admin November 1, 2017 Leave a comment

Questions:

I’d like to get dumps of each mysql table into separate files. The manual indicates that the syntax for this is

mysqldump [options] db_name [tbl_name ...]

Which indicates that you know the table names before hand. I could set up the script that knows each table name now, but say I add a new table down the road and forget to update the dump script. Then I’m missing dumps for one or more table.

Is there a way to automagically dump each existing table into a separate file? Or am I going to have to do some script-fu; query the database, get all the table names, and dump them by name.

If I go the script-fu route, what scripting langauges can access a mysql database?

Answers:

The mysqldump command line program does this for you – although the docs are very unclear about this.

One thing to note is that ~/output/dir has to be writable by the user that owns mysqld. On Mac OS X:

sudo chown -R _mysqld:_mysqld ~/output/dir
mysqldump --user=dbuser --password --tab=~/output/dir dbname

After running the above, you will have one tablename.sql file containing each table’s schema (create table statement) and tablename.txt file containing the data.

If you want a dump with schema only, add the –no-data flag:

mysqldump --user=dbuser --password --no-data --tab=~/output/dir dbname

Questions:
Answers:

Here’s a script that dumps table data as SQL commands into separate, compressed files. It does not require being on the MySQL server host, doesn’t hard-code the password in the script, and is just for a specific db, not all db’s on the server:

#!/bin/bash

# dump-tables-mysql.sh
# Descr: Dump MySQL table data into separate SQL files for a specified database.
# Usage: Run without args for usage info.
# Author: @Trutane
# Ref: http://stackoverflow.com/q/3669121/138325
# Notes:
#  * Script will prompt for password for db access.
#  * Output files are compressed and saved in the current working dir, unless DIR is
#    specified on command-line.

[ $# -lt 3 ] && echo "Usage: $(basename $0) <DB_HOST> <DB_USER> <DB_NAME> [<DIR>]" && exit 1

DB_host=$1
DB_user=$2
DB=$3
DIR=$4

[ -n "$DIR" ] || DIR=.
test -d $DIR || mkdir -p $DIR

echo -n "DB password: "
read -s DB_pass
echo
echo "Dumping tables into separate SQL command files for database '$DB' into dir=$DIR"

tbl_count=0

for t in $(mysql -NBA -h $DB_host -u $DB_user -p$DB_pass -D $DB -e 'show tables') 
do 
    echo "DUMPING TABLE: $DB.$t"
    mysqldump -h $DB_host -u $DB_user -p$DB_pass $DB $t | gzip > $DIR/$DB.$t.sql.gz
    tbl_count=$(( tbl_count + 1 ))
done

echo "$tbl_count tables dumped from database '$DB' into dir=$DIR"

Questions:
Answers:

You can accomplish this by:

  1. Get the list of databases in mysql
  2. dump each database with mysqldump
# Optional variables for a backup script
MYSQL_USER="root"
MYSQL_PASS="something"
BACKUP_DIR=/srv/backup/$(date +%Y-%m-%dT%H_%M_%S);
test -d "$BACKUP_DIR" || mkdir -p "$BACKUP_DIR"
# Get the database list, exclude information_schema
for db in $(mysql -B -s -u $MYSQL_USER --password=$MYSQL_PASS -e 'show databases' | grep -v information_schema)
do
  # dump each database in a separate file
  mysqldump -u $MYSQL_USER --password=$MYSQL_PASS "$db" | gzip > "$BACKUP_DIR/$db.sql.gz"
done

Questions:
Answers:

Here is the corresponding import.

#!/bin/bash

# import-files-mysql.sh
# Descr: Import separate SQL files for a specified database.
# Usage: Run without args for usage info.
# Author: Will Rubel
# Notes:
#  * Script will prompt for password for db access.

[ $# -lt 3 ] && echo "Usage: $(basename $0) <DB_HOST> <DB_USER> <DB_NAME> [<DIR>]" && exit 1

DB_host=$1
DB_user=$2
DB=$3
DIR=$4

DIR=$DIR/*


echo -n "DB password: "
read -s DB_pass
echo
echo "Importing separate SQL command files for database '$DB' into '$DB'"

file_count=0


for f in $DIR

do 
    echo "IMPORTING FILE: $f"

    gunzip -c $f | mysql -h $DB_host -u $DB_user -p$DB_pass $DB

    (( file_count++ ))
done

echo "$file_count files importing to database '$DB'"

Questions:
Answers:
#!/bin/bash

for i in $(mysql -uUser -pPASSWORD DATABASE -e "show tables;"|grep -v Tables_in_);do mysqldump -uUSER -pPASSWORD DATABASE $i > /backup/dir/$i".sql";done

tar -cjf "backup_mysql_"$(date +'%Y%m%d')".tar.bz2" /backup/dir/*.sql

Questions:
Answers:

It looks everybody here forgot of autocommit=0;SET unique_checks=0;SET foreign_key_checks=0; that is suppose to speed up the import process …

#!/bin/bash
MYSQL_USER="USER"
MYSQL_PASS="PASS"

if [ -z "$1" ]
  then
    echo "Dumping all DB ... in separate files"
    for I in $(mysql -u $MYSQL_USER --password=$MYSQL_PASS -e 'show databases' -s --skip-column-names); 
    do 
      echo "SET autocommit=0;SET unique_checks=0;SET foreign_key_checks=0;" > "$I.sql"
      mysqldump -u $MYSQL_USER --password=$MYSQL_PASS $I >> "$I.sql"; 
      echo "SET autocommit=1;SET unique_checks=1;SET foreign_key_checks=1;commit;" >> "$I.sql"
      gzip "$I.sql"
    done
    echo "END."
else
      echo "Dumping $1 ..."
      echo "SET autocommit=0;SET unique_checks=0;SET foreign_key_checks=0;" > "$1.sql"
      mysqldump -u $MYSQL_USER --password=$MYSQL_PASS $1 >> "$1.sql"; 
      echo "SET autocommit=1;SET unique_checks=1;SET foreign_key_checks=1;commit;" >> "$1.sql"
      gzip "$1.sql"
fi

Questions:
Answers:

I’m not bash master, but I’d just do it with a bash script. Without hitting MySQL, with knowledge of the data directory and database name, you could just scan for all .frm files (one for every table in that db/directory) for a list of tables.

I’m sure there are ways to make it slicker and accept arguments or whatnot, but this worked well for me.

tables_in_a_db_to_sql.sh

#!/bin/bash

database="this_is_my_database"
datadir="/var/lib/mysql/"
datadir_escaped="\/var\/lib\/mysql\/"

all_tables=($(ls $datadir$database/*.frm | sed s/"$datadir_escaped$database\/"/""/g | sed s/.frm//g))

for t in "${all_tables[@]}"; do
        outfile=$database.$t.sql
        echo "-- backing up $t to $outfile"
        echo "mysqldump [options] $database $t > $outfile"
        # mysqldump [options] $database $t > $outfile
done

Fill in the [options] and desired outfile convention as you need, and uncomment the last mysqldump line.

Questions:
Answers:

See the following article by Pauli Marcus:

Howto split a SQL database dump into table-wise files

Splitting a sql file containing a whole database into per-table files
is quite easy: Grep the .sql for any occurence of DROP TABLE. Generate
the file name from the table name that is included in the DROP TABLE
statement. Echo the output to a file. Here is a little script that
expects a .sql file as input:

#!/bin/bash

file=$1 # the input file
directory="$file-splitted" # the output directory
output="$directory/header" # the first file containing the header
GREP="DROP TABLE" # what we are looking for

mkdir $directory # create the output directory

while read line
do
   # if the current line contains the wanted statement
   if [ $(echo "$line" | grep -c "$GREP") == "1" ]
   then
      # extract the file name
      myfile=$(echo $line | awk '{print $5}' | sed -e 's/`//g' -e 's/;//g')
      # set the new file name
      output="$directory/$myfile"
   fi
       echo "$line" >> $output # write to file
done < $file