3 # Flush MySQL tables to the disk before the filesystem is frozen.
4 # At the same time, this keeps a read lock in order to avoid write accesses
5 # from the other clients until the filesystem is thawed.
8 MYSQL_OPTS="-uroot" #"-prootpassword"
9 FIFO=/var/run/mysql-flush.fifo
11 # Check mysql is installed and the server running
12 [ -x "$MYSQL" ] && "$MYSQL" $MYSQL_OPTS < /dev/null || exit 0
15 printf "FLUSH TABLES WITH READ LOCK \\G\n"
16 trap 'printf "$(date): $0 is killed\n">&2' HUP INT QUIT ALRM TERM
18 printf "UNLOCK TABLES \\G\n"
24 mkfifo $FIFO || exit 1
25 flush_and_wait | "$MYSQL" $MYSQL_OPTS &
26 # wait until every block is flushed
27 while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\
28 "$MYSQL" $MYSQL_OPTS | tail -1 | cut -f 2)" -gt 0 ]; do
31 # for InnoDB, wait until every log is flushed
32 INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX)
33 [ $? -ne 0 ] && exit 2
34 trap "rm -f $INNODB_STATUS; exit 1" HUP INT QUIT ALRM TERM
36 printf "SHOW ENGINE INNODB STATUS \\G" |\
37 "$MYSQL" $MYSQL_OPTS > $INNODB_STATUS
38 LOG_CURRENT=$(grep 'Log sequence number' $INNODB_STATUS |\
39 tr -s ' ' | cut -d' ' -f4)
40 LOG_FLUSHED=$(grep 'Log flushed up to' $INNODB_STATUS |\
41 tr -s ' ' | cut -d' ' -f5)
42 [ "$LOG_CURRENT" = "$LOG_FLUSHED" ] && break
49 [ ! -p $FIFO ] && exit 1