Patent: US 8,166,269

Assignee: Oracle

Priority Date: 11/5/09

Prior Art: Search Google Prior Art search for 8,166,269

I'm having trouble figuring out whether Oracle is claiming to have invented the method of an adjustable free-space low-water-mark threshold to trigger garbage collection.

I also observe that they don't provide a single complete sample algorithm for actually computing this threshold.

Claim 1:

A method of adaptively triggering garbage collection within a computer system, the method comprising:

  1. Initializing a data structure to comprise N empty buckets (N>0), wherein each bucket represents an amount of free memory;
  2. Periodically recording a rate of allocation of free memory; for each of multiple iterations of garbage collection:

    • calculating a mean rate of allocation of free memory prior to the iteration;
    • observing a drop in the free memory during the iteration;
    • reading the data structure to examine a bucket corresponding to the observed memory drop;
    • if the bucket is empty, storing in the bucket the calculated mean rate of allocation of free memory; and
    • if the bucket stores a rate of allocation higher than the calculated mean rate of allocation of free memory, replacing the stored rate of allocation with a new rate of allocation; and
    • if an increase in the rate of allocation of free memory is observed during said periodic recording, adjusting a free memory threshold at which the garbage collection is initiated.

Can someone help me parse this claim?

1 Answer 1


It looks likes an increasing mean rate of amount of memory allocated between garbage collections causes a raising of the threshold for garbage collection. Some claims are more specific than others. Regarding examples, an application has to enable someone skilled in the art to make and use the invention without undue experimentation and to not hide whatever way the inventor thinks is the best way of doing it at the time of filing.

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