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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/05/04 20:57:50 UTC
[GitHub] [arrow] westonpace commented on a diff in pull request #12672: ARROW-15779: [Python] Create python bindings for Substrait consumer
westonpace commented on code in PR #12672:
URL: https://github.com/apache/arrow/pull/12672#discussion_r865311231
##########
cpp/src/arrow/engine/substrait/util.h:
##########
@@ -0,0 +1,40 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <memory>
+#include "arrow/engine/substrait/api.h"
+#include "arrow/util/iterator.h"
+#include "arrow/util/optional.h"
+
+namespace arrow {
+
+namespace engine {
+
+/// \brief Retrieve a RecordBatchReader from a Substrait plan.
+ARROW_ENGINE_EXPORT Result<std::shared_ptr<RecordBatchReader>> ExecuteSerializedPlan(
+ std::shared_ptr<Buffer> substrait_buffer);
Review Comment:
This should be `const Buffer&`. That will require some changes to `SubstraitExecutor` but the way it is written right now we are keeping the plan alive for the entire time we execute it and that is incorrect. We only need the `substrait_buffer` to create the `ExecPlan` (happens in `SubstraitExecutor::Init`). Once that is done we should allow this buffer to be freed (it's not likely to be a huge chunk of RAM but it seems like good hygiene and the API will be clearer to the user).
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
+ std::shared_ptr<RecordBatchReader> sink_reader = compute::MakeGeneratorReader(
+ schema, std::move(*generator_), exec_context_.memory_pool());
+ return sink_reader;
+ }
+
+ Status Close() { return plan_->finished().status(); }
+
+ Status Init() {
Review Comment:
To solve the `substrait_buffer_` shared_ptr dilemma I mentioned earlier you could pass `const Buffer&` into `Init` and get rid of `substrait_buffer_`.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
+ std::shared_ptr<RecordBatchReader> sink_reader = compute::MakeGeneratorReader(
+ schema, std::move(*generator_), exec_context_.memory_pool());
+ return sink_reader;
+ }
+
+ Status Close() { return plan_->finished().status(); }
+
+ Status Init() {
+ if (substrait_buffer_ == NULLPTR) {
+ return Status::Invalid("Buffer containing Substrait plan is null.");
+ }
+ std::function<std::shared_ptr<compute::SinkNodeConsumer>()> consumer_factory = [&] {
+ return std::make_shared<SubstraitSinkConsumer>(generator_);
+ };
+ ARROW_ASSIGN_OR_RAISE(declarations_,
+ engine::DeserializePlan(*substrait_buffer_, consumer_factory));
+ return Status::OK();
+ }
+
+ private:
+ std::shared_ptr<Buffer> substrait_buffer_;
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator_;
+ std::vector<compute::Declaration> declarations_;
+ std::shared_ptr<compute::ExecPlan> plan_;
+ compute::ExecContext exec_context_;
+};
+
+arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer
+SubstraitSinkConsumer::MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen) {
+ arrow::PushGenerator<util::optional<compute::ExecBatch>> push_gen;
+ auto out = push_gen.producer();
+ *out_gen = std::move(push_gen);
+ return out;
+}
+} // namespace
+
+Result<std::shared_ptr<RecordBatchReader>> ExecuteSerializedPlan(
+ std::shared_ptr<Buffer> substrait_buffer) {
+ arrow::AsyncGenerator<util::optional<compute::ExecBatch>> sink_gen;
+ ARROW_ASSIGN_OR_RAISE(auto plan, compute::ExecPlan::Make());
+ compute::ExecContext exec_context(arrow::default_memory_pool(),
+ ::arrow::internal::GetCpuThreadPool());
Review Comment:
I don't think we need to fix this today but someday we should allow the user to supply their own `ExecContext`. It should be an optional parameter that defaults to `default_exec_context` but right now `default_exec_context` is serial which is a little silly so I don't want to make the change now. Can you add a `TODO(ARROW-15732)` comment here and I'll pick it up with that change (which updates `default_exec_context` to be parallel).
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
Review Comment:
Store the schema as a member variable.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
Review Comment:
Eventually we will want to write in backpressure here. It doesn't make sense to do as part of this PR because I think it's related to the question of whether the substrait consumer should just allow us to use the `SinkNode` directly (instead of a `ConsumingSinkNode`). Please make a follow-up PR.
##########
python/pyarrow/tests/test_substrait.py:
##########
@@ -0,0 +1,108 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import os
+import sys
+import pathlib
+import pytest
+
+import pyarrow as pa
+from pyarrow.lib import tobytes
+from pyarrow.lib import ArrowInvalid
+
+try:
+ import pyarrow.parquet as pq
+except ImportError:
+ pq = None
+
+try:
+ import pyarrow.substrait as substrait
+except ImportError:
+ substrait = None
+
+# Marks all of the tests in this module
+# Ignore these with pytest ... -m 'not substrait'
+pytestmark = [pytest.mark.parquet, pytest.mark.substrait]
Review Comment:
So at the moment `ARROW_SUBSTRAIT` implies `ARROW_DATASET`. However, that doesn't always have to be the case. One could build Substrait without datasets. They would be limited to plans which operate on in-memory (or in-plan) tables. I can't imagine we will really run into it. But still, it might be good to add `pytest.mark.dataset` just in case.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
+ std::shared_ptr<RecordBatchReader> sink_reader = compute::MakeGeneratorReader(
+ schema, std::move(*generator_), exec_context_.memory_pool());
+ return sink_reader;
+ }
+
+ Status Close() { return plan_->finished().status(); }
+
+ Status Init() {
+ if (substrait_buffer_ == NULLPTR) {
+ return Status::Invalid("Buffer containing Substrait plan is null.");
+ }
+ std::function<std::shared_ptr<compute::SinkNodeConsumer>()> consumer_factory = [&] {
+ return std::make_shared<SubstraitSinkConsumer>(generator_);
+ };
+ ARROW_ASSIGN_OR_RAISE(declarations_,
+ engine::DeserializePlan(*substrait_buffer_, consumer_factory));
+ return Status::OK();
+ }
+
+ private:
+ std::shared_ptr<Buffer> substrait_buffer_;
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator_;
+ std::vector<compute::Declaration> declarations_;
+ std::shared_ptr<compute::ExecPlan> plan_;
+ compute::ExecContext exec_context_;
+};
+
+arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer
+SubstraitSinkConsumer::MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen) {
+ arrow::PushGenerator<util::optional<compute::ExecBatch>> push_gen;
+ auto out = push_gen.producer();
+ *out_gen = std::move(push_gen);
+ return out;
+}
+} // namespace
+
+Result<std::shared_ptr<RecordBatchReader>> ExecuteSerializedPlan(
+ std::shared_ptr<Buffer> substrait_buffer) {
+ arrow::AsyncGenerator<util::optional<compute::ExecBatch>> sink_gen;
Review Comment:
There is no reason to declare this here. Just initialize `SubstraitExecutor::generator_` to `nullptr`.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
+ std::shared_ptr<RecordBatchReader> sink_reader = compute::MakeGeneratorReader(
+ schema, std::move(*generator_), exec_context_.memory_pool());
+ return sink_reader;
+ }
+
+ Status Close() { return plan_->finished().status(); }
+
+ Status Init() {
+ if (substrait_buffer_ == NULLPTR) {
+ return Status::Invalid("Buffer containing Substrait plan is null.");
+ }
+ std::function<std::shared_ptr<compute::SinkNodeConsumer>()> consumer_factory = [&] {
+ return std::make_shared<SubstraitSinkConsumer>(generator_);
Review Comment:
Make the `std::shared_ptr<SubstraitSinkConsumer>` a member variable for `SubstraitExecutor`.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
+ std::shared_ptr<RecordBatchReader> sink_reader = compute::MakeGeneratorReader(
+ schema, std::move(*generator_), exec_context_.memory_pool());
+ return sink_reader;
+ }
+
+ Status Close() { return plan_->finished().status(); }
+
+ Status Init() {
+ if (substrait_buffer_ == NULLPTR) {
+ return Status::Invalid("Buffer containing Substrait plan is null.");
+ }
+ std::function<std::shared_ptr<compute::SinkNodeConsumer>()> consumer_factory = [&] {
+ return std::make_shared<SubstraitSinkConsumer>(generator_);
+ };
+ ARROW_ASSIGN_OR_RAISE(declarations_,
+ engine::DeserializePlan(*substrait_buffer_, consumer_factory));
+ return Status::OK();
+ }
+
+ private:
+ std::shared_ptr<Buffer> substrait_buffer_;
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator_;
+ std::vector<compute::Declaration> declarations_;
+ std::shared_ptr<compute::ExecPlan> plan_;
+ compute::ExecContext exec_context_;
+};
+
+arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer
+SubstraitSinkConsumer::MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen) {
+ arrow::PushGenerator<util::optional<compute::ExecBatch>> push_gen;
+ auto out = push_gen.producer();
+ *out_gen = std::move(push_gen);
+ return out;
+}
+} // namespace
+
+Result<std::shared_ptr<RecordBatchReader>> ExecuteSerializedPlan(
+ std::shared_ptr<Buffer> substrait_buffer) {
+ arrow::AsyncGenerator<util::optional<compute::ExecBatch>> sink_gen;
+ ARROW_ASSIGN_OR_RAISE(auto plan, compute::ExecPlan::Make());
+ compute::ExecContext exec_context(arrow::default_memory_pool(),
+ ::arrow::internal::GetCpuThreadPool());
+ arrow::engine::SubstraitExecutor executor(std::move(substrait_buffer), &sink_gen,
+ std::move(plan), exec_context);
+ RETURN_NOT_OK(executor.Init());
+ ARROW_ASSIGN_OR_RAISE(auto sink_reader, executor.Execute());
+ RETURN_NOT_OK(executor.Close());
Review Comment:
This doesn't seem right to me. We shouldn't be waiting for the execution plan to finish. If we are going to do that we may as well return `arrow::Table` or `RecordBatchVector`. However, if we don't wait for it to close I see we will end up with a new dilemma. Something needs to keep the `ExecPlan` alive.
Instead, can we have `SubstraitExecutor` extend `RecordBatchReader`? `Execute` can store the `std::shared_ptr<RecordBatchReader>` as a member variable. You can just proxy the two virtual methods:
```
std::shared_ptr<Schema> SubstraitExecutor::schema() const override {
return sink_reader->schema();
}
Status SubstraitExecutor::ReadNext(std::shared_ptr<RecordBatch>* batch) override {
return sink_reader->ReadNext(batch);
}
```
This should allow us to return `SubstraitExecutor` itself instead of returning `sink_reader`. We should also, arguably, add a context manager for it in python so that `SubstraitExecutor::Close` is called as soon as python is done with it. Since `RecordBatchReader` does not have a close method I suppose that will be a new wrinkle in how we expose this to python.
We could either return `std::shared_ptr<RecordBatchReader>` and the "close" could be resetting the shared pointer This would still require some cython logic and probably a new python/cython class (CloseableRecordBatchReader?).
Or we could expose SubstraitExecutor in python.
Or we could create the new concept of a CloseableRecordBatchReader in C++ and python.
Or we could add Close to RecordBatchReader (which has a default implementation of doing nothing).
I think my preference would be for the last option there. CC @lidavidm for second opinion.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
Review Comment:
```suggestion
```
There is no need for this. When you call `Close` the push generator will take care of sending a terminal item.
##########
cpp/src/arrow/engine/substrait/util.cc:
##########
@@ -0,0 +1,139 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/engine/substrait/util.h"
+#include "arrow/util/async_generator.h"
+#include "arrow/util/async_util.h"
+
+namespace arrow {
+
+namespace engine {
+
+namespace {
+/// \brief A SinkNodeConsumer specialized to output ExecBatches via PushGenerator
+class SubstraitSinkConsumer : public compute::SinkNodeConsumer {
+ public:
+ explicit SubstraitSinkConsumer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator)
+ : producer_(MakeProducer(generator)) {}
+
+ Status Consume(compute::ExecBatch batch) override {
+ // Consume a batch of data
+ bool did_push = producer_.Push(batch);
+ if (!did_push) return Status::ExecutionError("Producer closed already");
+ return Status::OK();
+ }
+
+ Status Init(const std::shared_ptr<Schema>& schema,
+ compute::BackpressureControl* backpressure_control) override {
+ return Status::OK();
+ }
+
+ static arrow::PushGenerator<util::optional<compute::ExecBatch>>::Producer MakeProducer(
+ AsyncGenerator<util::optional<compute::ExecBatch>>* out_gen);
+
+ Future<> Finish() override {
+ producer_.Push(IterationEnd<util::optional<compute::ExecBatch>>());
+ ARROW_UNUSED(producer_.Close());
+ return Future<>::MakeFinished();
+ }
+
+ private:
+ PushGenerator<util::optional<compute::ExecBatch>>::Producer producer_;
+};
+
+/// \brief An executor to run a Substrait Query
+/// This interface is provided as a utility when creating language
+/// bindings for consuming a Substrait plan.
+class SubstraitExecutor {
+ public:
+ explicit SubstraitExecutor(
+ std::shared_ptr<Buffer> substrait_buffer,
+ AsyncGenerator<util::optional<compute::ExecBatch>>* generator,
+ std::shared_ptr<compute::ExecPlan> plan, compute::ExecContext exec_context)
+ : substrait_buffer_(std::move(substrait_buffer)),
+ generator_(generator),
+ plan_(std::move(plan)),
+ exec_context_(exec_context) {}
+
+ Result<std::shared_ptr<RecordBatchReader>> Execute() {
+ for (const compute::Declaration& decl : declarations_) {
+ RETURN_NOT_OK(decl.AddToPlan(plan_.get()).status());
+ }
+ RETURN_NOT_OK(plan_->Validate());
+ RETURN_NOT_OK(plan_->StartProducing());
+ // schema of the output can be obtained by the output_schema
+ // of the input to the sink node.
+ auto schema = plan_->sinks()[0]->inputs()[0]->output_schema();
Review Comment:
Rather than take this approach, if you store the sink consumer as a member variable (I added a comment to this effect) and, in the sink consumer's init step you store the schema as a member variable, then you can use the schema of the sink consumer here. I.e. this line should become:
```
auto schema = sink_consumer_->schema();
```
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