The context is as follows.

The buffer is now unpinned and is a candidate for immediate aging out, if the current contents (data block) are not referenced again.

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    I'm a native speaker with 20 years programming experience and don't understand what aging out means here. Hopefully the manual defines somewhere what they mean. Jun 28, 2011 at 14:37

3 Answers 3


This seems more like a programming/computer related question to me, due to the feel of the website you got the quote from.

However, it seems that the question is mostly answered by another quote from the same site:

The Oracle server uses the least recently used algorithm to age out buffers that have not been accessed recently to make room for new blocks in the database buffer cache.

This means that it retires those buffers from use; though, since I'm not a programmer, I don't know what happens to them after that.

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    In fact the buffers don't get retired from use - the data that's in them is discarded, to make room for more useful data. But the basic idea is the same :)
    – psmears
    Jun 28, 2011 at 9:21
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    In programming, a buffer is a place for storing data where you don't know ahead of time exactly how much data you will need to store. In this quote, the cache is a collection of buffers holding data that has been retrieved recently from the database. Each buffer's data is held in the cache in case it is requested again because retrieving it from the cache is much faster than retrieving it again from the database. The age of a buffer is how much time has passed since its data was last used. When new data is retrieved from the database, it replaces the data in the oldest buffer.
    – jimreed
    Jun 28, 2011 at 12:44
  • Actually, a buffer is a place for storing data that is coming or going, and one does know ahead of time exactly how much data you will need to store, or its maximum size. In the text at hand, these are data base buffers, for which the data size is almost always known ahead of time to be of a fixed size (a block size).
    – mgkrebbs
    Jun 28, 2011 at 18:16

As reported in the Wikipedia, aging out is "American popular culture vernacular used to describe anytime a youth leaves a formal system of care designed to provide services below a certain age level."
In the sentence you report, the phrasal verb is used figuratively. It means the buffer is released, and the memory it used returns in the free memory pool.

  • I saw that too, although if you copy the quote Yousui gave us and search for it on Google, you'll come up with the website I linked in my answer. Maybe you already saw that?
    – Daniel
    Jun 28, 2011 at 4:55
  • @drm65 I think it's just being used figuratively. In the original meaning, it means a youth leaves the care system; in the reported sentence, it means the buffer leaves the list of referenced buffers.
    – apaderno
    Jun 28, 2011 at 5:00
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    It can also mean compulsory superannuation of any sort, like reaching mandatory retirement age (particularly in establishments like the military) or age-restricted fraternal and service organisations. And yes, in the "garbage collection" sense, its use is merely figurative.
    – bye
    Jun 28, 2011 at 5:42
  • Since at least the 60s, the verbs "age in" and "age out" have been used by social/medical care workers (and analysts of their work) to mean the process by which people either become or cease to remain recipients of that care, by virtue of getting older. The computer sense is no more figurative than the social care management sense, and probably started about the same time if not before. Jun 28, 2011 at 12:38

To "age out" in general is to become ineligible or irrelevant by virtue of physical age.

It's used in many "junior" sports and competitions that are tied more to physical age than academic grade level. An example is DCI marching competitions; most drum corps are open to individuals from high school through college-age, but on a person's 25th birthday they are no longer eligible to compete; they have "aged out".

It's also used in certain other situations, such as government programs (you can "age out" of eligibility for health insurance coverage under your parents in the U.S.), non-profits, etc etc.

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