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Posted to commits@hudi.apache.org by "Udit Mehrotra (Jira)" <ji...@apache.org> on 2021/05/07 04:32:00 UTC
[jira] [Commented] (HUDI-1879) Spark DataSource
tables/HoodieFileIndex issues for Merge On Read
[ https://issues.apache.org/jira/browse/HUDI-1879?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17340557#comment-17340557 ]
Udit Mehrotra commented on HUDI-1879:
-------------------------------------
[~vinoth] [~pzw2018] Noticed a couple of blocking regressions after the two recent Spark PRs that we merged.
> Spark DataSource tables/HoodieFileIndex issues for Merge On Read
> ----------------------------------------------------------------
>
> Key: HUDI-1879
> URL: https://issues.apache.org/jira/browse/HUDI-1879
> Project: Apache Hudi
> Issue Type: Bug
> Components: Spark Integration
> Reporter: Udit Mehrotra
> Priority: Blocker
> Labels: sev:critical
>
> *Read as DataSource Tables* and *HoodieFileIndex* implementation that went in [https://github.com/apache/hudi/pull/2283] and [https://github.com/apache/hudi/pull/2651] has introduced a couple of major regressions for *Merge on Read* tables:
> * *_ro* *tables returning Snapshot results*: Since we are directly using Hudi DataSource now to query *_ro* and *_rt* MOR tables, the DataSource has no way to recognize the difference between read optimized and real time tables as it has no way to check for *table name*. In both these scenarios *{color:#172b4d}QUERY_TYPE_OPT_KEY{color}*{color:#172b4d} turns out to be *snapshot* by default, which is causing *MergeOnReadSnapshotRelation* to be used for querying thus returning snapshot results always.{color}
> * *{color:#172b4d}Partition pruning{color}* *{color:#172b4d}does not work{color}* *{color:#172b4d}for realtime queries{color}*{color:#172b4d}: The *MergeOnReadSnapshotRelation* is directly using *allFiles* to always fetch all the files without doing any partition pruning. This is a regression for Spark SQL real time queries because earlier partition pruning would work via InputFormat for these queries. Thus, it will have impact on rt queries performance.{color}
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