Return-Path: X-Original-To: apmail-hbase-issues-archive@www.apache.org Delivered-To: apmail-hbase-issues-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id C589211D3E for ; Thu, 19 Jun 2014 22:09:25 +0000 (UTC) Received: (qmail 36204 invoked by uid 500); 19 Jun 2014 22:09:25 -0000 Delivered-To: apmail-hbase-issues-archive@hbase.apache.org Received: (qmail 36156 invoked by uid 500); 19 Jun 2014 22:09:25 -0000 Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list issues@hbase.apache.org Received: (qmail 36143 invoked by uid 99); 19 Jun 2014 22:09:25 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 19 Jun 2014 22:09:25 +0000 Date: Thu, 19 Jun 2014 22:09:25 +0000 (UTC) From: "stack (JIRA)" To: issues@hbase.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HBASE-11323) BucketCache all the time! MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HBASE-11323?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14037985#comment-14037985 ] stack commented on HBASE-11323: ------------------------------- Two votes for #1 over in HBASE-11364 [BlockCache] Add a flag to cache data blocks in L1 if multi-tier cache > BucketCache all the time! > ------------------------- > > Key: HBASE-11323 > URL: https://issues.apache.org/jira/browse/HBASE-11323 > Project: HBase > Issue Type: Sub-task > Components: io > Reporter: stack > Fix For: 0.99.0 > > Attachments: ReportBlockCache.pdf > > > One way to realize the parent issue is to just enable bucket cache all the time; i.e. always have offheap enabled. Would have to do some work to make it drop-dead simple on initial setup (I think it doable). > So, upside would be the offheap upsides (less GC, less likely to go away and never come back because of full GC when heap is large, etc.). > Downside is higher latency. In Nick's BlockCache 101 there is little to no difference between onheap and offheap. In a basic compare doing scans and gets -- details to follow -- I have BucketCache deploy about 20% less ops than LRUBC when all incache and maybe 10% less ops when falling out of cache. I can't tell difference in means and 95th and 99th are roughly same (more stable with BucketCache). GC profile is much better with BucketCache -- way less. BucketCache uses about 7% more user CPU. > More detail on comparison to follow. > I think the numbers disagree enough we should probably do the [~lhofhansl] suggestion, that we allow you to have a table sit in LRUBC, something the current bucket cache layout does not do. -- This message was sent by Atlassian JIRA (v6.2#6252)