On Mon, Oct 19, 2009 at 4:29 AM, 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. cache trashing is really not that bad (as against system crashing with OOM). Documentation of softReference spcifically mentions caches as one of the applications http://java.sun.com/j2se/1.4.2/docs/api/java/lang/ref/SoftReference.html > > 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/ >> >> -- >> This message is automatically generated by JIRA. >> - >> You can reply to this email to add a comment to the issue online. >> >> > > > > -- > Lance Norskog > [email protected] >
-- ----------------------------------------------------- Noble Paul | Principal Engineer| AOL | http://aol.com
