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Hive QA commented on HIVE-20760: -------------------------------- | (x) *{color:red}-1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || || || || || {color:brown} Prechecks {color} || | {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s{color} | {color:green} The patch does not contain any @author tags. {color} | || || || || {color:brown} master Compile Tests {color} || | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 7m 44s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 16s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m 15s{color} | {color:green} master passed {color} | | {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m 30s{color} | {color:blue} common in master has 65 extant Findbugs warnings. {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 12s{color} | {color:green} master passed {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 0m 17s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 15s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m 15s{color} | {color:green} the patch passed {color} | | {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m 14s{color} | {color:red} common: The patch generated 1 new + 428 unchanged - 0 fixed = 429 total (was 428) {color} | | {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m 0s{color} | {color:green} The patch has no whitespace issues. {color} | | {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 0m 37s{color} | {color:red} common generated 2 new + 65 unchanged - 0 fixed = 67 total (was 65) {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 12s{color} | {color:green} the patch passed {color} | || || || || {color:brown} Other Tests {color} || | {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 12s{color} | {color:green} The patch does not generate ASF License warnings. {color} | | {color:black}{color} | {color:black} {color} | {color:black} 11m 8s{color} | {color:black} {color} | \\ \\ || Reason || Tests || | FindBugs | module:common | | | Inconsistent synchronization of org.apache.hadoop.hive.common.HiveConfProperties.interned; locked 74% of time Unsynchronized access at HiveConfProperties.java:74% of time Unsynchronized access at HiveConfProperties.java:[line 108] | | | org.apache.hadoop.hive.common.HiveConfProperties.getProperty(String, String) is unsynchronized, org.apache.hadoop.hive.common.HiveConfProperties.setProperty(String, String) is synchronized At HiveConfProperties.java:String) is synchronized At HiveConfProperties.java:[lines 123-130] | \\ \\ || Subsystem || Report/Notes || | Optional Tests | asflicense javac javadoc findbugs checkstyle compile | | uname | Linux hiveptest-server-upstream 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u1 (2016-09-03) x86_64 GNU/Linux | | Build tool | maven | | Personality | /data/hiveptest/working/yetus_PreCommit-HIVE-Build-15365/dev-support/hive-personality.sh | | git revision | master / ef7c396 | | Default Java | 1.8.0_111 | | findbugs | v3.0.0 | | checkstyle | http://104.198.109.242/logs//PreCommit-HIVE-Build-15365/yetus/diff-checkstyle-common.txt | | findbugs | http://104.198.109.242/logs//PreCommit-HIVE-Build-15365/yetus/new-findbugs-common.html | | modules | C: common U: common | | Console output | http://104.198.109.242/logs//PreCommit-HIVE-Build-15365/yetus.txt | | Powered by | Apache Yetus http://yetus.apache.org | This message was automatically generated. > Reducing memory overhead due to multiple HiveConfs > -------------------------------------------------- > > Key: HIVE-20760 > URL: https://issues.apache.org/jira/browse/HIVE-20760 > Project: Hive > Issue Type: Improvement > Components: Configuration > Reporter: Barnabas Maidics > Assignee: Barnabas Maidics > Priority: Major > Attachments: HIVE-20760-1.patch, HIVE-20760-2.patch, > HIVE-20760-3.patch, HIVE-20760.10.patch, HIVE-20760.11.patch, > HIVE-20760.12.patch, HIVE-20760.4.patch, HIVE-20760.5.patch, > HIVE-20760.6.patch, HIVE-20760.7.patch, HIVE-20760.8.patch, > HIVE-20760.9.patch, HIVE-20760.patch, hiveconf_interned.html, > hiveconf_original.html > > > The issue is that every Hive task has to load its own version of > {{HiveConf}}. When running with a large number of cores per executor (HoS), > there is a significant (~10%) amount of memory wasted due to this > duplication. > I looked into the problem and found a way to reduce the overhead caused by > the multiple HiveConf objects. > I've created an implementation of Properties, somewhat similar to > CopyOnFirstWriteProperties. CopyOnFirstWriteProperties can't be used to solve > this problem, because it drops the interned Properties right after we add a > new property. > So my implementation looks like this: > * When we create a new HiveConf from an existing one (copy constructor), we > change the properties object stored by HiveConf to the new Properties > implementation (HiveConfProperties). We have 2 possible way to do this. > Either we change the visibility of the properties field in the ancestor class > (Configuration which comes from hadoop) to protected, or a simpler way is to > just change the type using reflection. > * HiveConfProperties instantly intern the given properties. After this, > every time we add a new property to HiveConf, we add it to an additional > Properties object. This way if we create multiple HiveConf with the same base > properties, they will use the same Properties object but each session/task > can add its own unique properties. > * Getting a property from HiveConfProperties would look like this: (I stored > the non-interned properties in super class) > String property=super.getProperty(key); > if (property == null) property= interned.getProperty(key); > return property; > Running some tests showed that the interning works (with 50 connections to > HiveServer2, heapdumps created after sessions are created for queries): > Overall memory: > original: 34,599K interned: 20,582K > Retained memory of HiveConfs: > original: 16,366K interned: 10,804K > I attach the JXray reports about the heapdumps. > What are your thoughts about this solution? -- This message was sent by Atlassian JIRA (v7.6.3#76005)