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https://issues.apache.org/jira/browse/BEAM-7925?focusedWorklogId=481033&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-481033
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ASF GitHub Bot logged work on BEAM-7925:
----------------------------------------
Author: ASF GitHub Bot
Created on: 09/Sep/20 20:01
Start Date: 09/Sep/20 20:01
Worklog Time Spent: 10m
Work Description: danielxjd commented on a change in pull request #12786:
URL: https://github.com/apache/beam/pull/12786#discussion_r485887994
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -135,6 +135,20 @@
* ...
* }</pre>
*
+ * <p>Reading with projection can be enabled with the projection schema as
following. Splittable
+ * reading is enabled when reading with projection. The projection_schema
contains only the column
+ * that we would like to read and encoder_schema contains the schema to encode
the output with the
+ * unwanted columns changed to nullable. Partial reading provide increase of
reading time due to
Review comment:
should be decrease
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Issue Time Tracking
-------------------
Worklog Id: (was: 481033)
Time Spent: 2h 50m (was: 2h 40m)
> ParquetIO supports neither column projection nor filter predicate
> -----------------------------------------------------------------
>
> Key: BEAM-7925
> URL: https://issues.apache.org/jira/browse/BEAM-7925
> Project: Beam
> Issue Type: Improvement
> Components: io-java-parquet
> Affects Versions: 2.14.0
> Reporter: Neville Li
> Priority: P2
> Time Spent: 2h 50m
> Remaining Estimate: 0h
>
> Current {{ParquetIO}} supports neither column projection nor filter predicate
> which defeats the performance motivation of using Parquet in the first place.
> That's why we have our own implementation of
> [ParquetIO|https://github.com/spotify/scio/tree/master/scio-parquet/src] in
> Scio.
> Reading Parquet as Avro with column projection has some complications,
> namely, the resulting Avro records may be incomplete and will not survive
> ser/de. A workaround maybe provide a {{TypedRead}} interface that takes a
> {{Function<A, B>}} that maps invalid Avro {{A}} into user defined type {{B}}.
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