In the thread here:
http://thread.gmane.org/gmane.comp.lang.perl.modules.dbi.rose-db-object/2303/focus=2314
John suggested a new_or_cached() method and I agreed it was a good idea.
Attached is a patch against Rose::DB svn trunk that implements that method and 2
others (ping() and cache_ttl()). Test and docs included.
John, please let me know if this was the direction you wanted to take. I'd be
happy to re-work it.
pek
--
Peter Karman . http://peknet.com/ . [EMAIL PROTECTED]
Index: t/dbh_cache.t
===================================================================
--- t/dbh_cache.t (revision 0)
+++ t/dbh_cache.t (revision 0)
@@ -0,0 +1,40 @@
+#!/usr/bin/perl -w
+
+use strict;
+
+BEGIN {
+ require Test::More;
+ eval { require DBD::SQLite };
+
+ if ( $@ || $DBD::SQLite::VERSION < 1.08 || $ENV{'RDBO_NO_SQLITE'} ) {
+ Test::More->import(
+ skip_all => $ENV{'RDBO_NO_SQLITE'}
+ ? 'SQLite tests disabled'
+ : 'Missing DBD::SQLite 1.08+'
+ );
+ }
+ elsif ( $DBD::SQLite::VERSION == 1.13 )
+ {
+ Test::More->import( skip_all => 'DBD::SQLite 1.13 is broken' );
+ }
+ else {
+ Test::More->import( tests => 5 );
+ }
+}
+
+BEGIN {
+ require 't/test-lib.pl';
+ use_ok('Rose::DB');
+}
+
+Rose::DB->default_domain('test');
+Rose::DB->default_type('sqlite_admin');
+
+ok( my $db = Rose::DB->new_or_cached(), "new_or_cached db" );
+
+ok( ref $db && $db->isa('Rose::DB'), 'new()' );
+
+ok( my $db2 = Rose::DB->new_or_cached(), "new_or_cached db2" );
+
+is( $db->dbh, $db2->dbh, "same DBI handle used" );
+
Index: lib/Rose/DB.pm
===================================================================
--- lib/Rose/DB.pm (revision 1470)
+++ lib/Rose/DB.pm (working copy)
@@ -53,6 +53,20 @@
],
);
+use Rose::Class::MakeMethods::Generic
+(
+ hash =>
+ [
+ db_cache => { interface => 'get_set_all' },
+ db_cache_names => { interface => 'keys', hash_key => 'db_cache' },
+ db_cache_values => { interface => 'values', hash_key => 'db_cache' },
+ db_cache_exists => { interface => 'exists', hash_key => 'db_cache' },
+ delete_db_cache => { interface => 'delete', hash_key => 'db_cache' },
+ clear_db_cache => { interface => 'clear', hash_key => 'db_cache' },
+ reset_db_cache => { interface => 'reset', hash_key => 'db_cache' },
+ ],
+);
+
__PACKAGE__->default_domain('default');
__PACKAGE__->default_type('default');
@@ -119,6 +133,7 @@
'type',
'date_handler',
'server_time_zone',
+ 'cache_ttl',
#'class',
],
@@ -366,6 +381,64 @@
return $self;
}
+sub ping {
+ my $self = shift;
+ my $dbh = shift || $self->dbh;
+ my $ret = 0;
+ my $prev_alarm = 0;
+ eval {
+ local $SIG{__DIE__} = sub { return (0); };
+ local $SIG{__WARN__} = sub { return (0); };
+ local $SIG{ALRM} = sub { return (0); };
+
+ $prev_alarm = CORE::alarm(2);
+ $ret = $dbh->do("select 1");
+ };
+ $prev_alarm ? CORE::alarm($prev_alarm) : CORE::alarm(0);
+
+ return ($@) ? 0 : $ret;
+}
+
+sub new_or_cached
+{
+ my($self) = shift;
+ my $db = $self->new(@_);
+ if (!$self->db_cache)
+ {
+ $self->db_cache({});
+ }
+
+ my $id_str = join( '::', $db->domain, $db->type, $db->dsn );
+ my $cache = $self->db_cache_exists($id_str)
+ ? $self->db_cache->{$id_str}
+ : {};
+
+ if ( defined $cache->{dbh}
+ and ( time() - $cache->{birthday} ) < $db->cache_ttl
+ and $self->ping( $cache->{dbh} ) )
+ {
+ $cache->{access_count}++;
+ $db->dbh( $cache->{dbh} );
+ }
+ else {
+ if ( exists $cache->{dbh} ) {
+ $cache->{dbh}->disconnect; # explicitly disconnect old handle
+ }
+ my $dbh = $db->dbh;
+ $cache = {
+ dbh => $dbh,
+ birthday => time(),
+ access_count => 1,
+ id_str => $id_str,
+ };
+ $self->db_cache->{$id_str} = $cache;
+ }
+
+ $db->{'cached_dbh'} = 1;
+
+ return $db;
+}
+
sub class
{
my($self) = shift;
@@ -506,6 +579,8 @@
sub init_domain { shift->{'_origin_class'}->default_domain }
sub init_type { shift->{'_origin_class'}->default_type }
+sub init_cache_ttl { 3600 * 24 }
+
sub init_date_handler { Rose::DateTime::Format::Generic->new }
sub init_server_time_zone { 'floating' }
@@ -726,6 +801,8 @@
sub release_dbh
{
my($self, %args) = @_;
+
+ return 1 if $self->{'cached_dbh'};
my $dbh = $self->{'dbh'} or return 0;
@@ -2759,6 +2836,14 @@
You can change this mapping with the L<driver_class|/driver_class> class
method.
+=item B<new_or_cached PARAMS>
+
+Behaves like new() but uses a cached DBI handle. You can set the time to live
+for the cached handle with the L<cache_ttl> method. Every time new_or_cached()
+is called, the DBI handle is tested with the ping() method to ensure the
connection
+is still alive. If ping() fails, the cached handle is disconnect()ed and a
+new DBI handle is created and cached.
+
=back
=head1 OBJECT METHODS
@@ -2810,6 +2895,15 @@
Note: when setting this attribute, you I<must> pass in a L<DBI> database
handle that has the same L<driver|/driver> as the object. For example, if the
L<driver|/driver> is C<mysql> then the L<DBI> database handle must be connected
to a MySQL database. Passing in a mismatched database handle will cause a
fatal error.
+=item B<ping>
+
+Tickle the L<DBI> database handle to ensure the connection is still alive.
+
+=item B<cache_ttl>
+
+Set the number of seconds a cached L<DBI> handle will survive before it is
disconnected
+and destroyed. The default is 24 hours (3600 * 24).
+
=item B<disconnect>
Decrements the reference count for the database handle and disconnects it if
the reference count is zero. Regardless of the reference count, it sets the
L<dbh|/dbh> attribute to undef.
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