NAME

KiokuDB::LiveObjects - Live object set tracking

VERSION

version 0.55

SYNOPSIS

$live_objects->insert( $entry => $object );

$live_objects->insert( $id => $object );

my $id = $live_objects->object_to_id( $object );

my $obj = $live_objects->id_to_object( $id );

my $scope = $live_objects->new_scope;

DESCRIPTION

This object keeps track of the set of live objects, their associated IDs, and the storage entries.

ATTRIBUTES

clear_leaks

Boolean. Defaults to false.

If true, when the last known scope is removed but some objects are still live they will be removed from the live object set.

Note that this does NOT prevent leaks (memory cannot be reclaimed), it merely prevents stale objects from staying loaded.

leak_tracker

This is a coderef or object.

If any objects are leaked (see clear_leaks) then the this can be used to report them, or to break the circular structure.

When an object is provided the leaked_objects method is called. The coderef is simply invoked with the objects as arguments.

Triggered after clear_leaks causes clear to be called.

For example, to break cycles you can use Data::Structure::Util's circular_off function:

use Data::Structure::Util qw(circular_off);

$dir->live_objects->leak_tracker(sub {
    my @leaked_objects = @_;
    circular_off($_) for @leaked_objects;
});

keep_entries

EXPERIMENTAL

When true (the default), KiokuDB::Entries loaded from the backend or created by the collapser are kept around.

This results in a considerable memory overhead, so it's no longer required.

METHODS

insert

Takes pairs, id or entry as the key, and object as the value, registering the objects.

objects_to_ids

object_to_id

Given objects, returns their IDs, or undef for objects which not registered.

objects_to_entries

object_to_entry

Given objects, find the corresponding entries.

ids_to_objects

id_to_object

Given IDs, find the corresponding objects.

ids_to_entries

Given IDs, find the corresponding entries.

update_entries

Given entries, replaces the live entries of the corresponding objects with the newly updated ones.

The objects must already be in the live object set.

This method is called on a successful transaction commit.

new_scope

Creates a new KiokuDB::LiveObjects::Scope, with the current scope as its parent.

current_scope

The current KiokuDB::LiveObjects::Scope instance.

This is the scope into which newly registered objects are pushed.

new_txn

Creates a new KiokuDB::LiveObjects::TXNScope, with the current txn scope as its parent.

txn_scope

The current KiokuDB::LiveObjects::TXNScope.

clear

Forces a clear of the live object set.

This removes all objects and entries, and can be useful in the case of leaks (to prevent false positives on lookups).

Note that this does not actually break the circular structures, so the leak is unresolved, but the objects are no longer considered live by the KiokuDB instance.

live_entries

live_objects

live_ids

Enumerates the live entries, objects or ids.

rollback_entries

Called by "rollback" in KiokuDB::LiveObjects::TXNScope.

remove

Removes entries from the live object set.

remove_scope $scope

Removes a scope from the set of known scopes.

Also calls detach_scope, and calls KiokuDB::LiveObjects::Scope/clear on the scope itself.

detach_scope $scope

Detaches $scope if it's the current scope.

This prevents push from being called on this scope object implicitly anymore.

AUTHOR

Yuval Kogman <nothingmuch@woobling.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Yuval Kogman, Infinity Interactive.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.