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https://issues.apache.org/jira/browse/HIVE-14792?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16392093#comment-16392093
]
Hive QA commented on HIVE-14792:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
|| || || || {color:brown} Prechecks {color} ||
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m
1s{color} | {color:blue} Findbugs executables are not available. {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
8s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
0s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
35s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
51s{color} | {color:green} master passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
17s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m
57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
39s{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} javadoc {color} | {color:green} 0m
54s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:red}-1{color} | {color:red} asflicense {color} | {color:red} 0m
13s{color} | {color:red} The patch generated 49 ASF License warnings. {color} |
| {color:black}{color} | {color:black} {color} | {color:black} 13m 52s{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-9559/dev-support/hive-personality.sh
|
| git revision | master / 73ccc44 |
| Default Java | 1.8.0_111 |
| asflicense |
http://104.198.109.242/logs//PreCommit-HIVE-Build-9559/yetus/patch-asflicense-problems.txt
|
| modules | C: ql U: ql |
| Console output |
http://104.198.109.242/logs//PreCommit-HIVE-Build-9559/yetus.txt |
| Powered by | Apache Yetus http://yetus.apache.org |
This message was automatically generated.
> AvroSerde reads the remote schema-file at least once per mapper, per table
> reference.
> -------------------------------------------------------------------------------------
>
> Key: HIVE-14792
> URL: https://issues.apache.org/jira/browse/HIVE-14792
> Project: Hive
> Issue Type: Bug
> Affects Versions: 1.2.1, 2.1.0
> Reporter: Mithun Radhakrishnan
> Assignee: Aihua Xu
> Priority: Major
> Labels: TODOC2.2, TODOC2.4
> Fix For: 3.0.0, 2.4.0, 2.2.1
>
> Attachments: HIVE-14792.1.patch, HIVE-14792.3.patch,
> HIVE-14792.4.patch
>
>
> Avro tables that use "external" schema files stored on HDFS can cause
> excessive calls to {{FileSystem::open()}}, especially for queries that spawn
> large numbers of mappers.
> This is because of the following code in {{AvroSerDe::initialize()}}:
> {code:title=AvroSerDe.java|borderStyle=solid}
> public void initialize(Configuration configuration, Properties properties)
> throws SerDeException {
> // ...
> if (hasExternalSchema(properties)
> || columnNameProperty == null || columnNameProperty.isEmpty()
> || columnTypeProperty == null || columnTypeProperty.isEmpty()) {
> schema = determineSchemaOrReturnErrorSchema(configuration, properties);
> } else {
> // Get column names and sort order
> columnNames = Arrays.asList(columnNameProperty.split(","));
> columnTypes =
> TypeInfoUtils.getTypeInfosFromTypeString(columnTypeProperty);
> schema = getSchemaFromCols(properties, columnNames, columnTypes,
> columnCommentProperty);
>
> properties.setProperty(AvroSerdeUtils.AvroTableProperties.SCHEMA_LITERAL.getPropName(),
> schema.toString());
> }
> // ...
> }
> {code}
> For tables using {{avro.schema.url}}, every time the SerDe is initialized
> (i.e. at least once per mapper), the schema file is read remotely. For
> queries with thousands of mappers, this leads to a stampede to the handful
> (3?) datanodes that host the schema-file. In the best case, this causes
> slowdowns.
> It would be preferable to distribute the Avro-schema to all mappers as part
> of the job-conf. The alternatives aren't exactly appealing:
> # One can't rely solely on the {{column.list.types}} stored in the Hive
> metastore. (HIVE-14789).
> # {{avro.schema.literal}} might not always be usable, because of the
> size-limit on table-parameters. The typical size of the Avro-schema file is
> between 0.5-3MB, in my limited experience. Bumping the max table-parameter
> size isn't a great solution.
> If the {{avro.schema.file}} were read during query-planning, and made
> available as part of table-properties (but not serialized into the
> metastore), the downstream logic will remain largely intact. I have a patch
> that does this.
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