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https://issues.apache.org/jira/browse/BEAM-11460?focusedWorklogId=528163&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-528163
]
ASF GitHub Bot logged work on BEAM-11460:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 24/Dec/20 14:35
Start Date: 24/Dec/20 14:35
Worklog Time Spent: 10m
Work Description: iemejia commented on a change in pull request #13554:
URL: https://github.com/apache/beam/pull/13554#discussion_r548530734
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -152,6 +162,38 @@
* *
* }</pre>
*
+ * <h3>Reading records of an unknown schema</h3>
+ *
+ * <p>To read records from files whose schema is unknown at pipeline
construction time or differs
+ * between files, use {@link #parseGenericRecords(SerializableFunction)} - in
this case, you will
+ * need to specify a parsing function for converting each {@link
GenericRecord} into a value of your
+ * custom type.
+ *
+ * <p>For example:
+ *
+ * <pre>{@code
+ * Pipeline p = ...;
+ *
+ * PCollection<Foo> records =
+ * p.apply(ParquetIO.parseGenericRecords(new
SerializableFunction<GenericRecord, Foo>() {
+ * public Foo apply(GenericRecord record) {
+ * // If needed, access the schema of the record using
record.getSchema()
+ * return ...;
+ * }}));
+ *
+ * // For reading from filepatterns
+ * PCollection<String> filepatterns = p.apply(...);
Review comment:
`PCollection<FileIO.ReadableFile> files = p.apply(...)`
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -838,6 +1031,23 @@ public void close() throws IOException {
}
}
+ /**
+ * Passthrough function to provide seamless backward compatibility to
ParquetIO's functionality.
+ */
+ @VisibleForTesting
+ static class GenericRecordPassthroughFn
+ implements SerializableFunction<GenericRecord, GenericRecord> {
+
+ static GenericRecordPassthroughFn create() {
+ return new GenericRecordPassthroughFn();
Review comment:
Can you please make this a singleton.
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -618,12 +807,16 @@ public Progress getProgress() {
}
}
- static class ReadFn extends DoFn<FileIO.ReadableFile, GenericRecord> {
+ static class ReadFn<T> extends DoFn<FileIO.ReadableFile, T> {
private Class<? extends GenericData> modelClass;
- ReadFn(GenericData model) {
+ private final SerializableFunction<GenericRecord, T> parseFn;
+
+ ReadFn(GenericData model, SerializableFunction<GenericRecord, T>
parseFn) {
+
Review comment:
nit: remove space
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -152,6 +162,38 @@
* *
* }</pre>
*
+ * <h3>Reading records of an unknown schema</h3>
+ *
+ * <p>To read records from files whose schema is unknown at pipeline
construction time or differs
+ * between files, use {@link #parseGenericRecords(SerializableFunction)} - in
this case, you will
+ * need to specify a parsing function for converting each {@link
GenericRecord} into a value of your
+ * custom type.
+ *
+ * <p>For example:
+ *
+ * <pre>{@code
+ * Pipeline p = ...;
+ *
+ * PCollection<Foo> records =
+ * p.apply(ParquetIO.parseGenericRecords(new
SerializableFunction<GenericRecord, Foo>() {
+ * public Foo apply(GenericRecord record) {
+ * // If needed, access the schema of the record using
record.getSchema()
+ * return ...;
+ * }}));
+ *
+ * // For reading from filepatterns
+ * PCollection<String> filepatterns = p.apply(...);
+ *
+ * PCollection<Foo> records =
+ * filepatterns
Review comment:
files (for coherence with above doc)
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -152,6 +162,38 @@
* *
* }</pre>
*
+ * <h3>Reading records of an unknown schema</h3>
+ *
+ * <p>To read records from files whose schema is unknown at pipeline
construction time or differs
+ * between files, use {@link #parseGenericRecords(SerializableFunction)} - in
this case, you will
+ * need to specify a parsing function for converting each {@link
GenericRecord} into a value of your
+ * custom type.
+ *
+ * <p>For example:
+ *
+ * <pre>{@code
+ * Pipeline p = ...;
+ *
+ * PCollection<Foo> records =
+ * p.apply(ParquetIO.parseGenericRecords(new
SerializableFunction<GenericRecord, Foo>() {
+ * public Foo apply(GenericRecord record) {
+ * // If needed, access the schema of the record using
record.getSchema()
+ * return ...;
+ * }}));
+ *
+ * // For reading from filepatterns
+ * PCollection<String> filepatterns = p.apply(...);
+ *
+ * PCollection<Foo> records =
+ * filepatterns
+ * .apply(ParquetIO.parseFilesGenericRecords(new
SerializableFunction<GenericRecord, Foo>() {
+ * public Foo apply(GenericRecord record) {
+ * // If needed, access the schema of the record using
record.getSchema()
+ * return ...;
Review comment:
extra indent on comment + return
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Issue Time Tracking
-------------------
Worklog Id: (was: 528163)
Time Spent: 40m (was: 0.5h)
> Support reading Parquet files with unknown schema
> -------------------------------------------------
>
> Key: BEAM-11460
> URL: https://issues.apache.org/jira/browse/BEAM-11460
> Project: Beam
> Issue Type: New Feature
> Components: io-java-parquet
> Reporter: Anant Damle
> Priority: P1
> Labels: Parquet
> Original Estimate: 336h
> Time Spent: 40m
> Remaining Estimate: 0h
>
> Data engineers encounter times when schema of Parquet file is unknown at the
> time of writing the pipeline or multiple schema may be present in different
> files. Reading Parquet files using ParquetIO requires providing an Avro
> (equivalent) schema, Many a times its not possible to know the schema of the
> Parquet files.
> On the other hand
> [AvroIO|https://beam.apache.org/releases/javadoc/2.26.0/org/apache/beam/sdk/io/AvroIO.html]
> supports reading unknow schema files by providing a parse function :
> {{*#parseGenericRecords(SerializableFunction<GenericRecord,T>)*}}
> Supporting this functionality in ParquetIO is simple and requires minimal
> changes to the ParquetIO surface.
> {code}
> Pipeline p = ...;
> PCollection<String> filepatterns = p.apply(...);
> PCollection<Foo> records =
> filepatterns
> .apply(FileIO.matchAll())
> .apply(FileIO.readMatches())
> .apply(ParquetIO.parseGenericRecords(new
> SerializableFunction<GenericRecord, Foo>() {
> public Foo apply(GenericRecord record) {
> // If needed, access the schema of the record using
> record.getSchema()
> return ...;
> }
> }));
> {code}
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