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https://issues.apache.org/jira/browse/IMPALA-9741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17108158#comment-17108158
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WangSheng edited comment on IMPALA-9741 at 5/15/20, 10:37 AM:
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Hi [~boroknagyz][~tarmstrong], I have been thinking about how to implement
query iceberg by impala recently, and here is my initial desgin. I will write a
class named IcebergScanNode.java in frontend, and this class mainly contains
these functions:
* Transform impala conjunts to iceberg expressions, which means we can pushdown
some predicates to icebrg;
* Get specific data files from icebreg by these expressions, which stored in
hdfs;
* Use these specific data files to construct related thrift struct, such as
THdfsFileSplit/TScanRangerSpec;
* And then backend will.use these thrift structs to construct "SCAN HDFS" to
scan data, and this way we can reuse these code in backend.
And here is a very simple desgin:
!select-iceberg.jpg!
Still some questions need to be consider:
# If iceberg returns different format files, such as parquet/orc, does backend
can handle these files?
# if not, we may decide the table data format when create table, maybe by
tblproperties, like this: 'iceberg_table'='parquet'
was (Author: skyyws):
Hi [~boroknagyz][~tarmstrong], I have been thinking about how to implement
query iceberg by impala recently, and here is my initial desgin. I will write a
class named IcebergScanNode.java in frontend, and this class mainly contains
these functions:
* Transform impala conjunts to iceberg expressions, which means we can pushdown
some predicates to icebrg;
* Get specific data files from icebreg by these expressions, which stored in
hdfs;
* Use these specific data files to construct related thrift struct, such as
THdfsFileSplit/TScanRangerSpec;
* And then backend will.use these thrift structs to construct "SCAN HDFS" to
scan data, and this way we can reuse these code in backend.
And here is a very simple desgin:
!select-iceberg.png!
> Support query iceberg table by impala
> -------------------------------------
>
> Key: IMPALA-9741
> URL: https://issues.apache.org/jira/browse/IMPALA-9741
> Project: IMPALA
> Issue Type: Sub-task
> Reporter: WangSheng
> Assignee: WangSheng
> Priority: Major
> Attachments: select-iceberg.jpg
>
>
> Since we have submit an patch of supporting create iceberg table by impala in
> IMPALA-9688, we are preparing to implement iceberg table query by impala. But
> we need to read the impala and iceberg code deeply to determine how to do
> this.
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