There is a difference - weak references are not for very good for
caches - soft references (soft values here) are good for caches in
most jvms. They can be very nice. Weak refs are eagerly reclaimed -
it's suggested that impls should not eagerly reclaim soft refs.
- Mark
http://www.lucidimagination.com (mobile)
On Oct 19, 2009, at 8:22 PM, Lance Norskog <[email protected]> wrote:
"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
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Lance Norskog
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