[ 
https://issues.apache.org/jira/browse/HIVE-20484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16606628#comment-16606628
 ] 

Hive QA commented on HIVE-20484:
--------------------------------

| (/) *{color:green}+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}  9m 
 7s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  0m 
22s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  0m 
14s{color} | {color:green} master passed {color} |
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue}  0m 
35s{color} | {color:blue} hbase-handler in master has 15 extant Findbugs 
warnings. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  0m 
13s{color} | {color:green} master passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  0m 
23s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  0m 
22s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green}  0m 
22s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  0m 
13s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green}  0m 
 0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green}  0m 
38s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  0m 
13s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green}  0m 
14s{color} | {color:green} The patch does not generate ASF License warnings. 
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 12m 59s{color} | 
{color:black} {color} |
\\
\\
|| 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-13634/dev-support/hive-personality.sh
 |
| git revision | master / 50d5bbb |
| Default Java | 1.8.0_111 |
| findbugs | v3.0.0 |
| modules | C: hbase-handler U: hbase-handler |
| Console output | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13634/yetus.txt |
| Powered by | Apache Yetus    http://yetus.apache.org |


This message was automatically generated.



> Disable Block Cache By Default With HBase SerDe
> -----------------------------------------------
>
>                 Key: HIVE-20484
>                 URL: https://issues.apache.org/jira/browse/HIVE-20484
>             Project: Hive
>          Issue Type: Improvement
>          Components: HBase Handler
>    Affects Versions: 1.2.3, 2.4.0, 4.0.0, 3.2.0
>            Reporter: BELUGA BEHR
>            Assignee: BELUGA BEHR
>            Priority: Major
>         Attachments: HIVE-20484.1.patch, HIVE-20484.2.patch
>
>
> {quote}
> Scan instances can be set to use the block cache in the RegionServer via the 
> setCacheBlocks method. For input Scans to MapReduce jobs, this should be 
> false. 
> https://hbase.apache.org/book.html#perf.hbase.client.blockcache
> {quote}
> However, from the Hive code, we can see that this is not the case.
> {code}
> public static final String HBASE_SCAN_CACHEBLOCKS = "hbase.scan.cacheblock";
> ...
> String scanCacheBlocks = 
> tableProperties.getProperty(HBaseSerDe.HBASE_SCAN_CACHEBLOCKS);
> if (scanCacheBlocks != null) {
>   jobProperties.put(HBaseSerDe.HBASE_SCAN_CACHEBLOCKS, scanCacheBlocks);
> }
> ...
> String scanCacheBlocks = jobConf.get(HBaseSerDe.HBASE_SCAN_CACHEBLOCKS);
> if (scanCacheBlocks != null) {
>   scan.setCacheBlocks(Boolean.parseBoolean(scanCacheBlocks));
> }
> {code}
> In the Hive code, we can see that if {{hbase.scan.cacheblock}} is not 
> specified in the {{SERDEPROPERTIES}} then {{setCacheBlocks}} is not called 
> and the default value of the HBase {{Scan}} class is used.
> {code:java|title=Scan.java}
>   /**
>    * Set whether blocks should be cached for this Scan.
>    * <p>
>    * This is true by default.  When true, default settings of the table and
>    * family are used (this will never override caching blocks if the block
>    * cache is disabled for that family or entirely).
>    *
>    * @param cacheBlocks if false, default settings are overridden and blocks
>    * will not be cached
>    */
>   public Scan setCacheBlocks(boolean cacheBlocks) {
>     this.cacheBlocks = cacheBlocks;
>     return this;
>   }
> {code}
> Hive is doing full scans of the table with MapReduce/Spark and therefore, 
> according to the HBase docs, the default behavior here should be that blocks 
> are not cached.  Hive should set this value to "false" by default unless the 
> table {{SERDEPROPERTIES}} override this.
> {code:sql}
> -- Commands for HBase
> -- create 'test', 't'
> CREATE EXTERNAL TABLE test(value map<string,string>, row_key string) 
> STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
> WITH SERDEPROPERTIES (
> "hbase.columns.mapping" = "t:,:key",
> "hbase.scan.cacheblock" = "false"
> );
> {code}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Reply via email to