[improvement](hdfs) support hedged read #22634
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clang-tidy review says "All clean, LGTM! 👍" |
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clang-tidy review says "All clean, LGTM! 👍" |
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clang-tidy review says "All clean, LGTM! 👍" |
|
clang-tidy review says "All clean, LGTM! 👍" |
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run buildall |
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clang-tidy review says "All clean, LGTM! 👍" |
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clang-tidy review says "All clean, LGTM! 👍" |
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run buildall |
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(From new machine)TeamCity pipeline, clickbench performance test result: |
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PR approved by at least one committer and no changes requested. |
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PR approved by anyone and no changes requested. |
In some cases, the high load of HDFS may lead to a long time to read the data on HDFS,
thereby slowing down the overall query efficiency. HDFS Client provides Hedged Read.
This function can start another read thread to read the same data when a read request
exceeds a certain threshold and is not returned, and whichever is returned first will use the result.
eg:
create catalog regression properties (
'type'='hms',
'hive.metastore.uris' = 'thrift://172.21.16.47:7004',
'dfs.client.hedged.read.threadpool.size' = '128',
'dfs.client.hedged.read.threshold.millis' = "500"
);
In some cases, the high load of HDFS may lead to a long time to read the data on HDFS,
thereby slowing down the overall query efficiency. HDFS Client provides Hedged Read.
This function can start another read thread to read the same data when a read request
exceeds a certain threshold and is not returned, and whichever is returned first will use the result.
eg:
create catalog regression properties (
'type'='hms',
'hive.metastore.uris' = 'thrift://172.21.16.47:7004',
'dfs.client.hedged.read.threadpool.size' = '128',
'dfs.client.hedged.read.threshold.millis' = "500"
);
In some cases, the high load of HDFS may lead to a long time to read the data on HDFS,
thereby slowing down the overall query efficiency. HDFS Client provides Hedged Read.
This function can start another read thread to read the same data when a read request
exceeds a certain threshold and is not returned, and whichever is returned first will use the result.
eg:
create catalog regression properties (
'type'='hms',
'hive.metastore.uris' = 'thrift://172.21.16.47:7004',
'dfs.client.hedged.read.threadpool.size' = '128',
'dfs.client.hedged.read.threshold.millis' = "500"
);
5 participants
Proposed changes
In some cases, the high load of HDFS may lead to a long time to read the data on HDFS,
thereby slowing down the overall query efficiency. HDFS Client provides Hedged Read.
This function can start another read thread to read the same data when a read request
exceeds a certain threshold and is not returned, and whichever is returned first will use the result.
eg:
Further comments
If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...