Oh God. The title puns are getting worse and worse.
I started playing around with caching strategies for Data::ICal::DateTime and ended up with these three strategies.
All of them assume this function
sub get_name {
my $ics = shift;
my $span = shift;
my $start = ($span->start_is_open)? "infinite" : $span->start->epoch;
my $end = ($span->end_is_open)? "infinite" : $span->end->epoch;
return "$ics-$start-$end";
}
tie my %cache => 'DB_File', $filename, O_RDWR|O_CREAT, 0666;
memoize('events', NORMALIZER => 'get_name',
SCALAR_CACHE => [HASH => \%cache]);
my @events = events($ics, $span);
sub events {
my $ics = shift;
my $span = shift;
my $cal = Data::ICal->new( filename => $ics );
return $cal->events;
}
my $pixie = Pixie->new->connect('bdb:cache/cache.db');
my $name = get_name($ics, $set);
my $events = $pixie->get_object_named($name);
my @events;
if ($events) {
@events = @$events;
} else {
my $cal = Data::ICal->new( filename => $ics);
@events = $cal->events($set);
my $object = bless \@events, "Random";
$pixie->bind_name( $name => $object );
}
my @events;
my $name = get_name($ics, $set);
my $cache = "cache/$name.cache";
if (-e $cache) {
# stat to check the cache is still valid...
@events = @{ Storable::retrieve( $cache ) };
} else {
my $cal = Data::ICal->new( filename => $ics );
@events = $cal->events($span);
Storable::store \@events, $cache;
}
Benchmarked that gives -
Benchmark: timing 1000 iterations of memoize, pixie, storable...
memoize: 4 wallclock secs ( 3.47 usr + 0.06 sys = 3.53 CPU) @ 283.29/s (n=1000)
pixie: 13 wallclock secs (11.57 usr + 0.11 sys = 11.68 CPU) @ 85.62/s (n=1000)
storable: 4 wallclock secs ( 3.91 usr + 0.09 sys = 4.00 CPU) @ 250.00/s (n=1000)
Rate pixie storable memoize
pixie 85.6/s -- -66% -70%
storable 250/s 192% -- -12%
memoize 283/s 231% 13% --
Which is pretty respectable.
The full script I used to do this is here.
