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https://issues.apache.org/jira/browse/HIVE-21210?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16760214#comment-16760214
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Hive QA commented on HIVE-21210:
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| (x) *{color:red}-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:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 1m
28s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 6m
31s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
15s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
46s{color} | {color:green} master passed {color} |
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m
31s{color} | {color:blue} common in master has 65 extant Findbugs warnings.
{color} |
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 3m
42s{color} | {color:blue} ql in master has 2305 extant Findbugs warnings.
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| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
8s{color} | {color:green} master passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
24s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
37s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m
11s{color} | {color:red} common: The patch generated 6 new + 0 unchanged - 0
fixed = 6 total (was 0) {color} |
| {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m
34s{color} | {color:red} ql: The patch generated 4 new + 10 unchanged - 46
fixed = 14 total (was 56) {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
1s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 4m
23s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
3s{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.
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| {color:black}{color} | {color:black} {color} | {color:black} 25m 48s{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-15925/dev-support/hive-personality.sh
|
| git revision | master / 4a4b9ca |
| Default Java | 1.8.0_111 |
| findbugs | v3.0.0 |
| checkstyle |
http://104.198.109.242/logs//PreCommit-HIVE-Build-15925/yetus/diff-checkstyle-common.txt
|
| checkstyle |
http://104.198.109.242/logs//PreCommit-HIVE-Build-15925/yetus/diff-checkstyle-ql.txt
|
| modules | C: common ql U: . |
| Console output |
http://104.198.109.242/logs//PreCommit-HIVE-Build-15925/yetus.txt |
| Powered by | Apache Yetus http://yetus.apache.org |
This message was automatically generated.
> CombineHiveInputFormat Thread Pool Sizing
> -----------------------------------------
>
> Key: HIVE-21210
> URL: https://issues.apache.org/jira/browse/HIVE-21210
> Project: Hive
> Issue Type: Improvement
> Affects Versions: 4.0.0, 3.2.0
> Reporter: BELUGA BEHR
> Assignee: BELUGA BEHR
> Priority: Major
> Attachments: HIVE-21210.1.patch
>
>
> Threadpools.
> Hive uses threadpools in several different places and each implementation is
> a little different and requires different configurations. I think that Hive
> needs to reign in and standardize the way that threadpools are used and
> threadpools should scale automatically without manual configuration. At any
> given time, there are many hundreds of threads running in the HS2 as the
> number of simultaneous connections increases and they surely cause contention
> with one-another.
> Here is an example:
> {code:java|title=CombineHiveInputFormat.java}
> // max number of threads we can use to check non-combinable paths
> private static final int MAX_CHECK_NONCOMBINABLE_THREAD_NUM = 50;
> private static final int DEFAULT_NUM_PATH_PER_THREAD = 100;
> {code}
> When building the splits for a MR job, there are up to 50 threads running per
> query and there is not much scaling here, it's simply 1 thread : 100 files
> ratio. This implies that to process 5000 files, there are 50 threads, after
> that, 50 threads are still used. Many Hive jobs these days involve more than
> 5000 files so it's not scaling well on bigger sizes.
> This is not configurable (even manually), it doesn't change when the hardware
> specs increase, and 50 threads seems like a lot when a service must support
> up to 80 connections:
> [https://www.cloudera.com/documentation/enterprise/5/latest/topics/admin_hive_tuning.html]
> Not to mention, I have never seen a scenario where HS2 is running on a host
> all by itself and has the entire system dedicated to it. Therefore it should
> be more friendly and spin up fewer threads.
> I am attaching a patch here that provides a few features:
> * Common module that produces {{ExecutorService}} which caps the number of
> threads it spins up at the number of processors a host has. Keep in mind that
> a class may submit as much work units ({{Callables}} as they would like, but
> the number of threads in the pool is capped.
> * Common module for partitioning work. That is, allow for a generic
> framework for dividing work into partitions (i.e. batches)
> * Modify {{CombineHiveInputFormat}} to take advantage of both modules,
> performing its same duties in a more Java OO way that is currently implemented
> * Add a partitioning (batching) implementation that enforces partitioning of
> a {{Collection}} based on the natural log of the {{Collection}} size so that
> it scales more slowly than a simple 1:100 ratio.
> * Simplify unit test code for {{CombineHiveInputFormat}}
> My hope is to introduce these tools to {{CombineHiveInputFormat}} and then to
> drop it into other places. One of the things I will introduce here is a
> "direct thread" {{ExecutorService}} so that even if there is a configuration
> for a thread pool to be disabled, it will still use an {{ExecutorService}} so
> that the project can avoid logic like "if this function is services by a
> thread pool, use a {{ExecutorService}} (and remember to close it later!)
> otherwise, create a single thread" so that things like [HIVE-16949] can be
> avoided in the future. Everything will just use an {{ExecutorService}}.
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