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前のセクションで説明した多くのプロセスを自動化できます (セクション18.6.9「MySQL Cluster レプリケーションを使用した MySQL Cluster バックアップ」参照してください)。次の Perl スクリプト reset-slave.pl
は、これを行う方法の実例として役に立ちます。
#!/user/bin/perl -w
# file: reset-slave.pl
# Copyright ©2005 MySQL AB
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to:
# Free Software Foundation, Inc.
# 59 Temple Place, Suite 330
# Boston, MA 02111-1307 USA
#
# Version 1.1
######################## Includes ###############################
use DBI;
######################## Globals ################################
my $m_host='';
my $m_port='';
my $m_user='';
my $m_pass='';
my $s_host='';
my $s_port='';
my $s_user='';
my $s_pass='';
my $dbhM='';
my $dbhS='';
####################### Sub Prototypes ##########################
sub CollectCommandPromptInfo;
sub ConnectToDatabases;
sub DisconnectFromDatabases;
sub GetSlaveEpoch;
sub GetMasterInfo;
sub UpdateSlave;
######################## Program Main ###########################
CollectCommandPromptInfo;
ConnectToDatabases;
GetSlaveEpoch;
GetMasterInfo;
UpdateSlave;
DisconnectFromDatabases;
################## Collect Command Prompt Info ##################
sub CollectCommandPromptInfo
{
### Check that user has supplied correct number of command line args
die "Usage:\n
reset-slave >master MySQL host< >master MySQL port< \n
>master user< >master pass< >slave MySQL host< \n
>slave MySQL port< >slave user< >slave pass< \n
All 8 arguments must be passed. Use BLANK for NULL passwords\n"
unless @ARGV == 8;
$m_host = $ARGV[0];
$m_port = $ARGV[1];
$m_user = $ARGV[2];
$m_pass = $ARGV[3];
$s_host = $ARGV[4];
$s_port = $ARGV[5];
$s_user = $ARGV[6];
$s_pass = $ARGV[7];
if ($m_pass eq "BLANK") { $m_pass = '';}
if ($s_pass eq "BLANK") { $s_pass = '';}
}
############### Make connections to both databases #############
sub ConnectToDatabases
{
### Connect to both master and slave cluster databases
### Connect to master
$dbhM
= DBI->connect(
"dbi:mysql:database=mysql;host=$m_host;port=$m_port",
"$m_user", "$m_pass")
or die "Can't connect to Master Cluster MySQL process!
Error: $DBI::errstr\n";
### Connect to slave
$dbhS
= DBI->connect(
"dbi:mysql:database=mysql;host=$s_host",
"$s_user", "$s_pass")
or die "Can't connect to Slave Cluster MySQL process!
Error: $DBI::errstr\n";
}
################ Disconnect from both databases ################
sub DisconnectFromDatabases
{
### Disconnect from master
$dbhM->disconnect
or warn " Disconnection failed: $DBI::errstr\n";
### Disconnect from slave
$dbhS->disconnect
or warn " Disconnection failed: $DBI::errstr\n";
}
###################### Find the last good GCI ##################
sub GetSlaveEpoch
{
$sth = $dbhS->prepare("SELECT MAX(epoch)
FROM mysql.ndb_apply_status;")
or die "Error while preparing to select epoch from slave: ",
$dbhS->errstr;
$sth->execute
or die "Selecting epoch from slave error: ", $sth->errstr;
$sth->bind_col (1, \$epoch);
$sth->fetch;
print "\tSlave Epoch = $epoch\n";
$sth->finish;
}
####### Find the position of the last GCI in the binary log ########
sub GetMasterInfo
{
$sth = $dbhM->prepare("SELECT
SUBSTRING_INDEX(File, '/', -1), Position
FROM mysql.ndb_binlog_index
WHERE epoch > $epoch
ORDER BY epoch ASC LIMIT 1;")
or die "Prepare to select from master error: ", $dbhM->errstr;
$sth->execute
or die "Selecting from master error: ", $sth->errstr;
$sth->bind_col (1, \$binlog);
$sth->bind_col (2, \$binpos);
$sth->fetch;
print "\tMaster binary log = $binlog\n";
print "\tMaster binary log position = $binpos\n";
$sth->finish;
}
########## Set the slave to process from that location #########
sub UpdateSlave
{
$sth = $dbhS->prepare("CHANGE MASTER TO
MASTER_LOG_FILE='$binlog',
MASTER_LOG_POS=$binpos;")
or die "Prepare to CHANGE MASTER error: ", $dbhS->errstr;
$sth->execute
or die "CHANGE MASTER on slave error: ", $sth->errstr;
$sth->finish;
print "\tSlave has been updated. You may now start the slave.\n";
}
# end reset-slave.pl