From 051f7e279777acfeb06a6b388dfe16c5671d16f4 Mon Sep 17 00:00:00 2001
From: Andrew Yates <ayates@ebi.ac.uk>
Date: Wed, 25 Jul 2012 14:09:14 +0000
Subject: [PATCH] Delete a database with minimal lock interuptions and without
having to use direct data file access and flushes.
---
misc-scripts/db/remove_mysqldb.pl | 282 ++++++++++++++++++++++++++++++
1 file changed, 282 insertions(+)
create mode 100644 misc-scripts/db/remove_mysqldb.pl
diff --git a/misc-scripts/db/remove_mysqldb.pl b/misc-scripts/db/remove_mysqldb.pl
new file mode 100644
index 0000000000..942a45417b
--- /dev/null
+++ b/misc-scripts/db/remove_mysqldb.pl
@@ -0,0 +1,282 @@
+#!/usr/bin/env perl
+
+package Script;
+
+use strict;
+use warnings;
+
+use Carp;
+use DBI;
+use Getopt::Long qw/:config no_ignore_case auto_version bundling_override/;
+use Pod::Usage;
+
+sub args {
+ my ($self) = @_;
+ my $opts = { port => 3306, verbose => 0 };
+ GetOptions(
+ $opts, qw/
+ host|hostname|h=s
+ port|P=i
+ username|user|u=s
+ password|pass|p=s
+ databases|database|db=s@
+ verbose|v
+ log=s
+ help
+ man
+ /
+ ) or pod2usage(-verbose => 1, -exitval => 1);
+ pod2usage(-verbose => 1, -exitval => 0) if $opts->{help};
+ pod2usage(-verbose => 2, -exitval => 0) if $opts->{man};
+ $self->{opts} = $opts;
+ return;
+}
+
+my $rcsid = '$Revision$';
+our ($VERSION) = $rcsid =~ /(\d+\.\d+)/;
+
+sub run {
+ my ($class) = @_;
+ my $self = bless({}, $class);
+ $self->args();
+ $self->logging();
+ $self->process();
+
+ if ($self->{oldfh}) {
+ select($self->{oldfh});
+ }
+
+ return;
+}
+
+sub defaults {
+ my ($self) = @_;
+ my $o = $self->opts();
+
+ foreach my $required (qw/username databases host/) {
+ pod2usage(-msg => sprintf('No -%s specified', $required), -verbose => 2, -exitval => 1);
+ }
+ #Processing -opt 1 -opt 2,3 into opt => [1,2,3]
+ $self->_cmd_line_to_array('databases') if $o->{databases};
+
+ $self->v(q{Working with %d database(s)}, scalar(@{$o->{databases}}));
+
+ return;
+}
+
+sub logging {
+ my ($self) = @_;
+ my $o = $self->opts();
+ if ($o->{log}) {
+ $o->{verbose} = 1;
+ my $file = $o->{log};
+ open my $fh, '>', $file or die "Cannot open log file '${file}' for writing: $!";
+ my $oldfh = select($fh);
+ $self->{oldfh} = $oldfh;
+ }
+ return;
+}
+
+sub process {
+ my ($self) = @_;
+ my $databases = $self->opts()->{databases};
+ foreach my $db (@{$databases}) {
+ $self->v('Working with database %s', $db);
+ $self->dbh($db);
+ $self->delete_tables();
+ my $ddl = sprintf('drop database %s', $db);
+ $self->v(qq{\tRunning: '%s'}, $ddl);
+ $self->dbh()->do($ddl);
+ $self->clear_tables();
+ $self->clear_dbh();
+ }
+ return;
+}
+
+sub delete_tables {
+ my ($self) = @_;
+ my @tables = keys %{ $self->tables() };
+ foreach my $table (@tables) {
+ $self->v(q{Processing '%s'}, $table);
+ my @sql;
+ if($self->is_view($table)) {
+ $self->v(q{'%s' is a view; just dropping}, $table);
+ push(@sql, 'drop view '.$table);
+ }
+ else {
+ $self->v(q{'%s' is being truncated and then dropped}, $table);
+ push(@sql,
+ 'truncate table '.$table,
+ 'drop table '.$table,
+ );
+ }
+
+ foreach my $statement (@sql) {
+ $self->v(qq{\tRunning: '%s'}, $statement);
+ $self->dbh()->do($statement);
+ }
+ }
+ return;
+}
+
+sub v {
+ my ($self, $msg, @args) = @_;
+ return unless $self->opts()->{verbose};
+ my $s_msg = sprintf($msg, @args);
+ my ($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst) =
+ localtime(time());
+ print sprintf("[%02d-%02d-%04d %02d:%02d:%02d] %s\n",
+ $mday, $mon, $year + 1900,
+ $hour, $min, $sec, $s_msg);
+ return;
+}
+
+sub dbh {
+ my ($self, $database) = @_;
+ if (!exists $self->{'dbh'}) {
+ my $o = $self->opts();
+ my %args = (host => $o->{host}, port => $o->{port});
+ $args{database} = $database if defined $database;
+
+ my $dsn =
+ 'DBI:mysql:' . join(q{;}, map { $_ . '=' . $args{$_} } keys %args);
+ $self->v('DBI connection URI %s', $dsn);
+ my $dbh =
+ DBI->connect($dsn, $o->{username}, $o->{password}, { RaiseError => 1 });
+
+ $self->{dbh} = $dbh;
+ }
+ return $self->{'dbh'};
+}
+
+sub clear_dbh {
+ my ($self) = @_;
+ if (exists $self->{dbh}) {
+ $self->{dbh}->disconnect();
+ delete $self->{dbh};
+ }
+ return;
+}
+
+sub is_view {
+ my ($self, $table) = @_;
+ return ($self->tables()->{$table} eq 'VIEW') ? 1 : 0;
+}
+
+sub tables {
+ my ($self) = @_;
+ if (!exists $self->{tables}) {
+ my $array =
+ $self->dbh()->selectcol_arrayref(
+'select TABLE_NAME, TABLE_TYPE from information_schema.TABLES where TABLE_SCHEMA = DATABASE()',
+ { Columns => [ 1, 2 ] }
+ );
+ my %hits = @{$array};
+ $self->{tables} = \%hits;
+ }
+ return $self->{tables};
+}
+
+sub clear_tables {
+ my ($self) = @_;
+ delete $self->{tables};
+ return;
+}
+
+sub _cmd_line_to_array {
+ my ($self, $key) = @_;
+ my $array = $self->opts()->{$key};
+ $array = (ref($array) && ref($array) eq 'ARRAY') ? $array : [$array];
+ my $string = join(q{,}, @{$array});
+ my @new_array = split(/,/, $string);
+ $self->opts()->{$key} = \@new_array;
+ return;
+}
+
+Script->run();
+
+1;
+__END__
+
+=pod
+
+=head1 NAME
+
+remove_mysqldb.pl
+
+=head1 SYNOPSIS
+
+ #Basic
+ ./remove_mysqldb.pl -username USER -password PASS -host HOST [-port PORT] -database DB [-verbose] [-help | -man]
+
+ #Advanced
+ ./remove_mysqldb.pl -username USER -password PASS -host HOST -port PORT -database DB -database DBTWO -verbose
+
+=head1 DESCRIPTION
+
+A script which is used to drop a database in the most lock friendly way.
+If you issue a C<drop database DB> command to MySQL it first aquires
+a C<LOCK_open> which is a global mutex always applied for when you open
+and close a file. Once the drop command has the lock no other process can
+query the MySQL DB until the lock is relinquished once the DB has been dropped.
+If your DB is very large or has a large number of tables this can take a long
+time and has you performing a denile of service attack on your own DB server.
+
+=head1 OPTIONS
+
+=over 8
+
+=item B<--username | --user | -u>
+
+REQUIRED. Username of the connecting account. Must be able to perform
+drop and truncate calls.
+
+=item B<--password | -pass | -p>
+
+Password of the connecting user.
+
+=item B<--host | --hostname | -h>
+
+REQUIRED. Host name of the database to connect to
+
+=item B<--port | -P>
+
+Optional integer of the database port. Defaults to 3306
+
+=item B<--databases | --database | --db>
+
+Allows database name specification and can be used more than once. Comma
+separated values are supported.
+
+=item B<--verbose>
+
+Makes the program give more information about what is going on. Otherwise
+the program is silent.
+
+=item B<--log>
+
+If given the script will write all logs to output. Switches on C<--verbose>
+
+=item B<--help>
+
+Help message
+
+=item B<--man>
+
+Man page
+
+=back
+
+=head1 REQUIREMENTS
+
+=over 8
+
+=item Perl 5.8+
+
+=item DBI
+
+=item DBD::mysql
+
+=back
+
+=cut
\ No newline at end of file
--
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