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Mon, 28 May 2018 08:00:00 +0200

MySQL

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Admin

Nützlich

ANALYSE

Mon, 01 Jan 0001 00:00:00 +0000

ANALYSE TABLE table_schema.table_name;

SELECT * FROM table_schema.table_name PROCEDURE ANALYSE() \G
SELECT foo, bar FROM table_schema.table_name PROCEDURE ANALYSE() \G

Backup Restore

Mon, 01 Jan 0001 00:00:00 +0000

export DB="holodoc"

# -- master-data=2 nur falls binlog aktiviert
time mysqldump -u ???? -p -h localhost  \
    --master-data=2            \
    --quick                    \
    --single-transaction       \
    --events                   \
    --flush-logs               \
    --lock-tables              \
    --quote-names              \
    --set-charset              \
    --create-options           \
    --extended-insert          \
    --add-locks                \
    --disable-keys             \
    --skip-add-drop-table      \
    --no-create-db             \
    --ignore-table=mysql.event \
    --databases ${DB}  | gzip > $HOSTNAME.${DB}.master.dump.$(date +%Y%m%d_%H%M%S).sql.gz

Ergibt dann:

-- CHANGE MASTER TO MASTER_LOG_FILE='....-mysql-bin.00nnnn', MASTER_LOG_POS=nnn;
USE `....`;

CREATE TABLE `....` (
  `ID` int(10) unsigned NOT NULL AUTO_INCREMENT,

Somit keine Gefahr eines fälschlichen DROP TABLE …
Später Restore in beliebige DB möglich (weil DB Name nicht in SQL File)

Nur Struktur:

export DB=holodoc
time mysqldump -u ???? -p --no-data --create-options --databases $DB |
gzip > $HOSTNAME.$DB.no-data.dump.$(date +%Y%m%d_%H%M%S).sql.gz

Benutzer, Rechte

Mon, 01 Jan 0001 00:00:00 +0000

-- Zeige alle Rechte (des aktuellen Users), resp eines bestimmten
SHOW GRANTS;
SHOW GRANTS FOR user;

SELECT
        user
      , host
      , password
  FROM mysql.user
  ORDER BY user, password, host
;

SELECT
        host
      , db
      , user
  FROM mysql.db
  ORDER BY db, host, user
;

SELECT *
  FROM mysql.tables_priv
  ORDER BY db, host
;

Binary Logs

Mon, 01 Jan 0001 00:00:00 +0000

SHOW BINARY LOGS;
PURGE BINARY LOGS TO 'mysql-bin.000nnn';
PURGE BINARY LOGS BEFORE '2015-04-10 22:46:26';

SET GLOBAL expire_logs_days=5;
FLUSH LOGS;

SHOW BINLOG EVENTS LIMIT 0,30;
SHOW BINLOG EVENTS IN 'mysql-bin.000nn' LIMIT 10;

mysqlbinlog /var/lib/mysql/mysqld-relay-bin.000140 | tail -20

cd $HOME/tmp
for file in /var/log/mysql/mysql-bin.00nnn*; do
    echo "mysqlbinlog $file > " $(basename $file).txt;
done

cd $HOME/tmp
for file in /var/lib/mysql/mysqld-relay-bin.00nnn*; do
    echo "mysqlbinlog $file > " $(basename $file).txt;
done

Data Dictionary

Mon, 01 Jan 0001 00:00:00 +0000

-- Liste aller Datenbanken
SHOW DATABASES;
-- eine zum Default machen (in aktueller Session)
USE db_name;
-- Liste aller Tabellen
SHOW TABLES;
-- stammt aus sqlplus (Oracle)
DESCRIBE tbl_name

-- zeige Struktur einer Tabelle in einer Datanbank
SHOW      COLUMNS FROM tbl_name FROM db_name;
SHOW FULL COLUMNS FROM tbl_name FROM db_name;

-- Erstelle DDL einer Tabelle
SHOW CREATE TABLE tbl_name \G

-- Zeige Indizes einer Tabelle in einer Datenbank
SHOW INDEX FROM tbl_name FROM db_name;

-- Eckdaten aller Tabellen einer Datenbank
SHOW TABLE STATUS FROM db_name \G

Datenbanken verschieben

Mon, 01 Jan 0001 00:00:00 +0000

mkdir -p          /srv/var/lib/mysql
chmod -R 755      /srv/var/lib
chmod 700         /srv/var/lib/mysql
chown mysql:mysql /srv/var/lib/mysql

/etc/init.d/mysql stop
mv  /var/lib/mysql/big_db_1 /srv/var/lib/mysql/
cd  /var/lib/mysql/
ln -s /srv/var/lib/mysql/big_db_1 .
/etc/init.d/mysql start

Dynamisches SQL

Mon, 01 Jan 0001 00:00:00 +0000

-- Dynamisches SQL:
-- z.B. ALTER TABLE Statements, die danach (via Copy/Paste)
-- ausgeführt werden können
 SELECT CONCAT('ALTER TABLE ', table_schema ,'.',table_name, ' ENGINE=InnoDB;')
   FROM information_schema.tables
   WHERE table_type='BASE TABLE' and engine <> 'InnoDB'
 ;

-- ANALYZE TABLE
SELECT CONCAT('ANALYZE TABLE ', table_schema ,'.',table_name, ' ;')
   FROM information_schema.tables
   WHERE table_schema LIKE '%%'
   ORDER BY table_schema, table_name
 ;

-- ANALYZE TABLE
SELECT CONCAT('ANALYZE NO_WRITE_TO_BINLOG TABLE ', table_schema ,'.',table_name, ' ;')
   FROM information_schema.tables
   WHERE table_schema = DATABASE()
   ORDER BY table_schema, table_name
 ;

SELECT CONCAT('SELECT * FROM ', table_name, ' PROCEDURE ANALYSE() \G')
   FROM information_schema.tables
   WHERE table_schema = DATABASE()
   ORDER BY table_schema, table_name
 ;

SELECT CONCAT('SELECT ', column_name ,' FROM ', table_name, ' PROCEDURE ANALYSE();')
   FROM information_schema.columns
   WHERE table_schema = DATABASE()
   ORDER BY table_schema, table_name, ordinal_position
 ;

Explain

Mon, 01 Jan 0001 00:00:00 +0000

Explain

USE db_name;

EXPLAIN          select * from tbl_name where ... like '%';
EXPLAIN EXTENDED select * from tbl_name where ... like '%';

-- dazu dann oft auch
SHOW INDEX FROM tbl_name;

Flush

Mon, 01 Jan 0001 00:00:00 +0000

FLUSH TABLES

FLUSH LOGS;
FLUSH TABLES WITH READ LOCK;
UNLOCK TABLES;

Transaction => Binlog Flush

innodb_flush_log_at_trx_commit=1

The default value of 1 is required for full ACID compliance. With this value, the log buffer is written out to the log file at each transaction commit and the flush to disk operation is performed on the log file.

innodb_flush_log_at_trx_commit=0

With a value of 0, any mysqld process crash can erase the last second of transactions. The log buffer is written out to the log file once per second and the flush to disk operation is performed on the log file, but nothing is done at a transaction commit.