Merge Shortest Paths

Find out who is keeping alive a set of objects.

Motivation

Having found an expensive object it is then important to find all the reasons it is kept alive.

Explanation

Unlike the Path to GC roots query, this query can operate on multiple objects. However, it only finds the shortest path to GC roots; there may be other paths, but this query does not show them. As it operates on multiple objects there are multiple paths, and the query has the option to merge objects on a path by class. Seeing a common path can be useful in understanding why a set of objects is being kept alive.

Arguments

Argument	Description
objects	Objects for which paths to garbage collection roots should be found.
-excludes	Fields of certain classes which should be ignored when finding paths. For example this allows paths through Weak or Soft Reference referents to be ignored. This is of the format `class name pattern` [: `field name` [, `field name` ]*]. Subclasses of the class are also included. If no field names are specified for the class then all fields are excluded.
-groupby	Whether to show: Merge Paths from GC Roots merged paths from garbage collection roots to the objects Merge Paths from GC Roots on Class merged paths from garbage collection roots to the objects grouped by class, so all objects of the same class are shown as one Merge to GC Roots on Class merged paths from the objects to garbage collection roots grouped by class, so all objects of the same class are shown as one

Result

The tree shows objects or sets of objects grouped by class on a path to or from GC roots. The Referenced Objects column shows how many of the objects supplied to this query are on a path through this row.

The context menu allows the objects on this segment of the path, or the referenced objects through this path to be separately examined with other queries.

Merge shortest paths from GC roots Result of a merge shortest paths query, showing a tree view starting from GC roots.

Note: With Merge Paths from GC Roots and Merge from GC Roots on Class the arrows in each Icon of a piece of paper with an arrow at the bottom right pointing down and to the right.

Icon of a piece of paper with an arrow at the bottom right pointing down and to the right.

icon points down and to the right, showing that the objects or objects of a line refer via the field in bold to the following object or objects in the tree view which is down and to the right. The Merge from GC Roots on Class does not show field names as different objects may refer to the following objects by different fields.

Merge shortest paths from GC roots on class Result of a merge shortest paths query, showing a tree view starting from GC roots, but merged on classes.

Result of a merge shortest paths query, showing a tree view starting from GC roots, but merged on classes.

Note: See the menu option to switch between the different groupby options.

Merge shortest paths to GC roots on class Result of a merge shortest paths query, showing a tree view starting from the objects, merged on classes, going to GC roots.

Result of a merge shortest paths query, showing a tree view starting from the objects, merged on classes, going to GC roots.

Note: With Merge to GC Roots on Class the arrows in each Icon of a piece of paper with an arrow at the top left pointing up and to the left.

icon points up and to the left, showing that the object or objects of a line actually refer to the preceding objects in the tree view which is up and to the left.