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Posted to issues@hive.apache.org by "Hive QA (JIRA)" <ji...@apache.org> on 2018/09/06 20:05:00 UTC
[jira] [Commented] (HIVE-20484) Disable Block Cache By Default With
HBase SerDe
[ https://issues.apache.org/jira/browse/HIVE-20484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16606337#comment-16606337 ]
Hive QA commented on HIVE-20484:
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| (/) *{color:green}+1 overall{color}* |
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|| 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} 8m 39s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 19s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m 11s{color} | {color:green} master passed {color} |
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m 31s{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 21s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 20s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m 20s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m 12s{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 11s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 13s{color} | {color:green} The patch does not generate ASF License warnings. {color} |
| {color:black}{color} | {color:black} {color} | {color:black} 12m 13s{color} | {color:black} {color} |
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|| 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-13629/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-13629/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
>
>
> {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}
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