"Soft references" then. "Weak pointers" is an older term. (They're
"weak" because some bully can steal their candy.)

On Sun, Oct 18, 2009 at 8:37 PM, Jason Rutherglen
<[email protected]> wrote:
> Lance,
>
> Do you mean soft references?
>
> On Sun, Oct 18, 2009 at 3:59 PM, Lance Norskog <[email protected]> wrote:
>> -1 for weak references in caching.
>>
>> This makes memory management less deterministic (predictable) and at
>> peak can cause cache-thrashing. In other words, the worst case gets
>> even more worse. When designing a system I want predictability and I
>> want to control the worst case, because system meltdowns are caused by
>> the worst case. Having thousands of small weak references does the
>> opposite.
>>
>> On Sat, Oct 17, 2009 at 2:00 AM, Noble Paul (JIRA) <[email protected]> wrote:
>>>
>>>    [ 
>>> https://issues.apache.org/jira/browse/SOLR-1513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12766864#action_12766864
>>>  ]
>>>
>>> Noble Paul commented on SOLR-1513:
>>> ----------------------------------
>>>
>>> bq.Google Collections is already checked in as a dependency of Carrot 
>>> clustering.
>>>
>>> in that e need to move it to core.
>>>
>>> Jason . We do not need to remove the original option. We can probably add 
>>> an extra parameter say softRef="true" or something. That way , we are not 
>>> screwing up anything and perf benefits can be studied separately.
>>>
>>>
>>>> Use Google Collections in ConcurrentLRUCache
>>>> --------------------------------------------
>>>>
>>>>                 Key: SOLR-1513
>>>>                 URL: https://issues.apache.org/jira/browse/SOLR-1513
>>>>             Project: Solr
>>>>          Issue Type: Improvement
>>>>          Components: search
>>>>    Affects Versions: 1.4
>>>>            Reporter: Jason Rutherglen
>>>>            Priority: Minor
>>>>             Fix For: 1.5
>>>>
>>>>         Attachments: google-collect-snapshot.jar, SOLR-1513.patch
>>>>
>>>>
>>>> ConcurrentHashMap is used in ConcurrentLRUCache.  The Google Colletions 
>>>> concurrent map implementation allows for soft values that are great for 
>>>> caches that potentially exceed the allocated heap.  Though I suppose Solr 
>>>> caches usually don't use too much RAM?
>>>> http://code.google.com/p/google-collections/
>>>
>>> --
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>>>
>>>
>>
>>
>>
>> --
>> Lance Norskog
>> [email protected]
>>
>



-- 
Lance Norskog
[email protected]

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