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https://issues.apache.org/jira/browse/HDFS-17593?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18091690#comment-18091690
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ASF GitHub Bot commented on HDFS-17593:
---------------------------------------
steveloughran commented on code in PR #8561:
URL: https://github.com/apache/hadoop/pull/8561#discussion_r3476329252
##########
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestOpenFileWithLocatedBlocks.java:
##########
@@ -66,12 +63,13 @@ public class TestOpenFileWithLocatedBlocks {
private static final EnumSet<CreateEncryptionZoneFlag> NO_TRASH =
EnumSet.of(CreateEncryptionZoneFlag.NO_TRASH);
- private MiniDFSCluster cluster;
- private DistributedFileSystem fs;
- private Configuration conf;
+ private static MiniDFSCluster cluster;
+ private static DistributedFileSystem fs;
+ private static Configuration conf;
+ private static Path ezPath;
- @BeforeEach
- public void setUp() throws IOException {
+ @BeforeAll
+ public static void setUp() throws Exception {
Review Comment:
very minor, just call this "setupCluster" and "teardownCluster".
setUp/tearDown have were the per method calls in junit1, and it's easy for
people who have read too many tests to get mixed up.
> Allow setting block locations when opening streams
> --------------------------------------------------
>
> Key: HDFS-17593
> URL: https://issues.apache.org/jira/browse/HDFS-17593
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Csaba Ringhofer
> Priority: Major
> Labels: pull-request-available
>
> The HDFS client seems to always get block locations from the namenode when
> opening a file:
> https://github.com/apache/hadoop/blob/4525c7e35ea22d7a6350b8af10eb8d2ff68376e7/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSClient.java#L1099
> This leads to unnecessary RPCs in Apache Impala when doing reads, as the
> block locations are cached globally and the executors already have a good
> guess about the block locations when opening a stream. Unless the cached
> block locations are stale ideally no RPC should be made to the namenode.
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