kiokudb::linker(3pm) [debian man page]

KiokuDB::Linker(3pm)					User Contributed Perl Documentation				      KiokuDB::Linker(3pm)

NAME

       KiokuDB::Linker - Relinks live objects from storage entries

SYNOPSIS

	   # mostly internal

DESCRIPTION

       The linker reconnects entry data, recreating the connected object graph in memory.

       The linkage process starts with an ID (or several IDs) to be loaded passed to the "get_or_load_objects" method.

       This ID will first be searched for in the live object set (KiokuDB::LiveObjects). If the object is already live, then it will be returned
       as is.

       If the object is not live, then the corresponding entry is fetched from the backend, and expanded into an actual instance.

       Expansion consults the KiokuDB::TypeMap using KiokuDB::TypeMap::Resolver, to find the correct typemap entry (see "COLLAPSING STRATEGIES" in
       KiokuDB::Collapser and KiokuDB::TypeMap), and that is used for the actual expansion.

       Most of the grunt work is delegated by the entries back to the linker using the "inflate_data" method, which handles circular structures,
       retrying of tied structures, etc.

       Inflated objects are registered with KiokuDB::LiveObjects, and get inserted into the current live object scope
       (KiokuDB::LiveObjects::Scope). The scope's job is to maintain a reference count of at least 1 for any loaded object, until it is destroyed
       itself. This ensures that weak references are not destroyed prematurely, but allows their use in order to avoid memory leaks.

perl v5.12.4							    2010-10-11						      KiokuDB::Linker(3pm)

KiokuDB::LiveObjects(3pm)				User Contributed Perl Documentation				 KiokuDB::LiveObjects(3pm)

NAME

       KiokuDB::LiveObjects - Live object set tracking

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.

perl v5.12.4							    2011-03-31						 KiokuDB::LiveObjects(3pm)