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https://issues.apache.org/jira/browse/TEZ-4397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17682391#comment-17682391
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Syed Shameerur Rahman edited comment on TEZ-4397 at 1/31/23 5:26 AM:
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[~abstractdog]
On debugging i found that This was due Hive’s operator initialization which are
designed in a way that only one split can be opened at a time since they share
the
[IOContext|https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/io/IOContext.java]
variable so when multiple splits are opened at the same time the shared
variable gets overwritten and doesn’t match the correct context.
I will take this up separately in Hive, But for Tez I have created a new PR
with the following changes
1. Disable the feature by default (no. of reader = 1)
2. Minor refactoring
was (Author: srahman):
[~abstractdog]
On debugging i found that This was due Hive’s operator initialization which are
designed in a way that only one split can be opened at a time since they share
the
[IOContext|https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/io/IOContext.java]
variable so when multiple splits are opened at the same time the shared
variable gets overwritten and doesn’t match the correct context.
I will take this up separately in Hive, But for Tez I have created a new PR
with the following changes
1. Disable the feature by default (no. of reader = 1)
> Open Tez Input splits asynchronously
> ------------------------------------
>
> Key: TEZ-4397
> URL: https://issues.apache.org/jira/browse/TEZ-4397
> Project: Apache Tez
> Issue Type: Task
> Reporter: Ramesh Kumar Thangarajan
> Assignee: Ramesh Kumar Thangarajan
> Priority: Major
> Time Spent: 2h 40m
> Remaining Estimate: 0h
>
> Tez input splits can be opened asynchronously. This will reduce the amount of
> time spent for s3 to prepare the connection and opening the object.
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