[jira] [Commented] (ARROW-2307) [Python] Unable to read arrow stream containing 0 record batches
[
https://issues.apache.org/jira/browse/ARROW-2307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16399687#comment-16399687
]
ASF GitHub Bot commented on ARROW-2307:
---
wesm closed pull request #1747: ARROW-2307: [Python] Allow reading record batch
streams with zero record batches
URL: https://github.com/apache/arrow/pull/1747
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git a/ci/msvc-build.bat b/ci/msvc-build.bat
index beefee6c0..a29ef0bad 100644
--- a/ci/msvc-build.bat
+++ b/ci/msvc-build.bat
@@ -69,7 +69,8 @@ if "%JOB%" == "Build_Debug" (
)
conda create -n arrow -q -y python=%PYTHON% ^
- six pytest setuptools numpy pandas cython ^
+ six pytest setuptools numpy pandas ^
+ cython=0.27.3 ^
thrift-cpp=0.11.0
call activate arrow
diff --git a/ci/travis_script_python.sh b/ci/travis_script_python.sh
index a776c4263..247d10278 100755
--- a/ci/travis_script_python.sh
+++ b/ci/travis_script_python.sh
@@ -41,7 +41,7 @@ conda install -y -q pip \
cloudpickle \
numpy=1.13.1 \
pandas \
- cython
+ cython=0.27.3
# ARROW-2093: PyTorch increases the size of our conda dependency stack
# significantly, and so we have disabled these tests in Travis CI for now
diff --git a/cpp/src/arrow/table-test.cc b/cpp/src/arrow/table-test.cc
index 24c8d5e15..b1cf6e59a 100644
--- a/cpp/src/arrow/table-test.cc
+++ b/cpp/src/arrow/table-test.cc
@@ -374,6 +374,17 @@ TEST_F(TestTable, FromRecordBatches) {
ASSERT_RAISES(Invalid, Table::FromRecordBatches({batch1, batch2}, ));
}
+TEST_F(TestTable, FromRecordBatchesZeroLength) {
+ // ARROW-2307
+ MakeExample1(10);
+
+ std::shared_ptr result;
+ ASSERT_OK(Table::FromRecordBatches(schema_, {}, ));
+
+ ASSERT_EQ(0, result->num_rows());
+ ASSERT_TRUE(result->schema()->Equals(*schema_));
+}
+
TEST_F(TestTable, ConcatenateTables) {
const int64_t length = 10;
diff --git a/cpp/src/arrow/table.cc b/cpp/src/arrow/table.cc
index ed5858624..f6ac6dd3b 100644
--- a/cpp/src/arrow/table.cc
+++ b/cpp/src/arrow/table.cc
@@ -297,14 +297,9 @@ std::shared_ptr Table::Make(const
std::shared_ptr& schema,
return std::make_shared(schema, arrays, num_rows);
}
-Status Table::FromRecordBatches(const
std::vector& batches,
+Status Table::FromRecordBatches(const std::shared_ptr& schema,
+const
std::vector& batches,
std::shared_ptr* table) {
- if (batches.size() == 0) {
-return Status::Invalid("Must pass at least one record batch");
- }
-
- std::shared_ptr schema = batches[0]->schema();
-
const int nbatches = static_cast(batches.size());
const int ncolumns = static_cast(schema->num_fields());
@@ -332,6 +327,15 @@ Status Table::FromRecordBatches(const
std::vector&
return Status::OK();
}
+Status Table::FromRecordBatches(const
std::vector& batches,
+std::shared_ptr* table) {
+ if (batches.size() == 0) {
+return Status::Invalid("Must pass at least one record batch");
+ }
+
+ return FromRecordBatches(batches[0]->schema(), batches, table);
+}
+
Status ConcatenateTables(const std::vector& tables,
std::shared_ptr* table) {
if (tables.size() == 0) {
diff --git a/cpp/src/arrow/table.h b/cpp/src/arrow/table.h
index 7274fca4d..20d027d6a 100644
--- a/cpp/src/arrow/table.h
+++ b/cpp/src/arrow/table.h
@@ -169,9 +169,25 @@ class ARROW_EXPORT Table {
const
std::vector& arrays,
int64_t num_rows = -1);
- // Construct table from RecordBatch, but only if all of the batch schemas are
- // equal. Returns Status::Invalid if there is some problem
+ /// \brief Construct table from RecordBatches, using schema supplied by the
first
+ /// RecordBatch.
+ ///
+ /// \param[in] batches a std::vector of record batches
+ /// \param[out] table the returned table
+ /// \return Status Returns Status::Invalid if there is some problem
+ static Status FromRecordBatches(
+ const std::vector& batches,
+ std::shared_ptr* table);
+
+ /// Construct table from RecordBatches, using supplied schema. There may be
+ /// zero record batches
+ ///
+ /// \param[in] schema the arrow::Schema for each batch
+ /// \param[in] batches a std::vector of record batches
+ /// \param[out] table the returned table
+ /// \return Status
static Status FromRecordBatches(
+ const std::shared_ptr& schema,
const std::vector& batches,
std::shared_ptr* table);
diff --git
[jira] [Commented] (ARROW-2307) [Python] Unable to read arrow stream containing 0 record batches
[
https://issues.apache.org/jira/browse/ARROW-2307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16399684#comment-16399684
]
ASF GitHub Bot commented on ARROW-2307:
---
wesm commented on issue #1747: ARROW-2307: [Python] Allow reading record batch
streams with zero record batches
URL: https://github.com/apache/arrow/pull/1747#issuecomment-373223120
+1. Appveyor build looking good:
https://ci.appveyor.com/project/wesm/arrow/build/1.0.1776
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> [Python] Unable to read arrow stream containing 0 record batches
>
>
> Key: ARROW-2307
> URL: https://issues.apache.org/jira/browse/ARROW-2307
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
>Affects Versions: 0.8.0
>Reporter: Benjamin Duffield
>Assignee: Wes McKinney
>Priority: Major
> Labels: pull-request-available
>
> Using java arrow I'm creating an arrow stream, using the stream writer.
>
> Sometimes I don't have anything to serialize, and so I don't write any record
> batches. My arrow stream thus consists of just a schema message.
> {code:java}
>
>
> {code}
> I am able to deserialize this arrow stream correctly using the java stream
> reader, but when reading it with python I instead hit an error
> {code}
> import pyarrow as pa
> # ...
> reader = pa.open_stream(stream)
> df = reader.read_all().to_pandas()
> {code}
> produces
> {code}
> File "ipc.pxi", line 307, in pyarrow.lib._RecordBatchReader.read_all
> File "error.pxi", line 77, in pyarrow.lib.check_status
> ArrowInvalid: Must pass at least one record batch
> {code}
> i.e. we're hitting the check in
> https://github.com/apache/arrow/blob/apache-arrow-0.8.0/cpp/src/arrow/table.cc#L284
> The workaround we're currently using is to always ensure we serialize at
> least one record batch, even if it's empty. However, I think it would be nice
> to either support a stream without record batches or explicitly disallow this
> and then match behaviour in java.
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[jira] [Commented] (ARROW-2307) [Python] Unable to read arrow stream containing 0 record batches
[
https://issues.apache.org/jira/browse/ARROW-2307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16399055#comment-16399055
]
ASF GitHub Bot commented on ARROW-2307:
---
wesm opened a new pull request #1747: ARROW-2307: [Python] Allow reading record
batch streams with zero record batches
URL: https://github.com/apache/arrow/pull/1747
This is a pretty rough edge case -- it would be good to get this fix into
0.9.0.
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> [Python] Unable to read arrow stream containing 0 record batches
>
>
> Key: ARROW-2307
> URL: https://issues.apache.org/jira/browse/ARROW-2307
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
>Affects Versions: 0.8.0
>Reporter: Benjamin Duffield
>Assignee: Wes McKinney
>Priority: Major
> Labels: pull-request-available
>
> Using java arrow I'm creating an arrow stream, using the stream writer.
>
> Sometimes I don't have anything to serialize, and so I don't write any record
> batches. My arrow stream thus consists of just a schema message.
> {code:java}
>
>
> {code}
> I am able to deserialize this arrow stream correctly using the java stream
> reader, but when reading it with python I instead hit an error
> {code}
> import pyarrow as pa
> # ...
> reader = pa.open_stream(stream)
> df = reader.read_all().to_pandas()
> {code}
> produces
> {code}
> File "ipc.pxi", line 307, in pyarrow.lib._RecordBatchReader.read_all
> File "error.pxi", line 77, in pyarrow.lib.check_status
> ArrowInvalid: Must pass at least one record batch
> {code}
> i.e. we're hitting the check in
> https://github.com/apache/arrow/blob/apache-arrow-0.8.0/cpp/src/arrow/table.cc#L284
> The workaround we're currently using is to always ensure we serialize at
> least one record batch, even if it's empty. However, I think it would be nice
> to either support a stream without record batches or explicitly disallow this
> and then match behaviour in java.
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[jira] [Commented] (ARROW-2307) [Python] Unable to read arrow stream containing 0 record batches
[
https://issues.apache.org/jira/browse/ARROW-2307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16398813#comment-16398813
]
Wes McKinney commented on ARROW-2307:
-
Working on a fix for this
> [Python] Unable to read arrow stream containing 0 record batches
>
>
> Key: ARROW-2307
> URL: https://issues.apache.org/jira/browse/ARROW-2307
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
>Affects Versions: 0.8.0
>Reporter: Benjamin Duffield
>Assignee: Wes McKinney
>Priority: Major
>
> Using java arrow I'm creating an arrow stream, using the stream writer.
>
> Sometimes I don't have anything to serialize, and so I don't write any record
> batches. My arrow stream thus consists of just a schema message.
> {code:java}
>
>
> {code}
> I am able to deserialize this arrow stream correctly using the java stream
> reader, but when reading it with python I instead hit an error
> {code}
> import pyarrow as pa
> # ...
> reader = pa.open_stream(stream)
> df = reader.read_all().to_pandas()
> {code}
> produces
> {code}
> File "ipc.pxi", line 307, in pyarrow.lib._RecordBatchReader.read_all
> File "error.pxi", line 77, in pyarrow.lib.check_status
> ArrowInvalid: Must pass at least one record batch
> {code}
> i.e. we're hitting the check in
> https://github.com/apache/arrow/blob/apache-arrow-0.8.0/cpp/src/arrow/table.cc#L284
> The workaround we're currently using is to always ensure we serialize at
> least one record batch, even if it's empty. However, I think it would be nice
> to either support a stream without record batches or explicitly disallow this
> and then match behaviour in java.
--
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