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https://issues.apache.org/jira/browse/IMPALA-10475?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17279237#comment-17279237
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Tim Armstrong commented on IMPALA-10475:
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I think I was a bit sloppy saying "traditional", we don't use that in the doc.
I guess maybe we should actually just say that it does apply to all
filesystem-based tables - transactional tables will be strongly consistent
anyway, so the user-facing behaviour will be the same as if SYNC_DDL was used.
Maybe we can just weave it into the original sentence "Although INSERT is
classified as a DML statement, when the SYNC_DDL option is enabled, INSERT
statements on filesystem-based tables ..."
> SYNC_DDL docs should clarify that it only affects DML
> -----------------------------------------------------
>
> Key: IMPALA-10475
> URL: https://issues.apache.org/jira/browse/IMPALA-10475
> Project: IMPALA
> Issue Type: Task
> Components: Docs
> Reporter: Tim Armstrong
> Assignee: shajini thayasingh
> Priority: Major
>
> https://impala.apache.org/docs/build/html/topics/impala_sync_ddl.html
> {noformat}
> Although INSERT is classified as a DML statement, when the SYNC_DDL option is
> enabled, INSERT statements also delay their completion until all the
> underlying data and metadata changes are propagated to all Impala nodes.
> Internally, Impala inserts have similarities with DDL statements in
> traditional database systems, because they create metadata needed to track
> HDFS block locations for new files and they potentially add new partitions to
> partitioned tables.
> {noformat}
> I saw someone read this as applying to all tables (Kudu, HBase, etc) but it
> only inherently applies to traditional non-transactional filesystem-based
> tables. It also applies to transactional tables until IMPALA-8631 is fixed,
> after which they will be more strongly consistent.
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