[
https://issues.apache.org/jira/browse/BEAM-8292?focusedWorklogId=408532&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-408532
]
ASF GitHub Bot logged work on BEAM-8292:
----------------------------------------
Author: ASF GitHub Bot
Created on: 24/Mar/20 04:20
Start Date: 24/Mar/20 04:20
Worklog Time Spent: 10m
Work Description: youngoli commented on pull request #11197: [BEAM-8292]
Portable Reshuffle for Go SDK
URL: https://github.com/apache/beam/pull/11197#discussion_r396853348
##########
File path: sdks/go/pkg/beam/core/runtime/exec/reshuffle.go
##########
@@ -0,0 +1,170 @@
+// 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.
+
+package exec
+
+import (
+ "bytes"
+ "context"
+ "fmt"
+ "io"
+ "math/rand"
+
+ "github.com/apache/beam/sdks/go/pkg/beam/core/graph/coder"
+ "github.com/apache/beam/sdks/go/pkg/beam/internal/errors"
+)
+
+// ReshuffleInput is a Node.
+type ReshuffleInput struct {
+ UID UnitID
+ SID StreamID
+ Coder *coder.Coder // Coder for the input PCollection.
+ Seed int64
+ Out Node
+
+ r *rand.Rand
+ enc ElementEncoder
+ wEnc WindowEncoder
+ b bytes.Buffer
+ // ret is a cached allocations for passing to the next Unit. Units
never modify the passed in FullValue.
+ ret FullValue
+}
+
+// ID returns the unit debug id.
+func (n *ReshuffleInput) ID() UnitID {
+ return n.UID
+}
+
+// Up initializes the value and window encoders, and the random source.
+func (n *ReshuffleInput) Up(ctx context.Context) error {
+ n.enc = MakeElementEncoder(coder.SkipW(n.Coder))
+ n.wEnc = MakeWindowEncoder(n.Coder.Window)
+ n.r = rand.New(rand.NewSource(n.Seed))
+ return nil
+}
+
+// StartBundle is a no-op.
+func (n *ReshuffleInput) StartBundle(ctx context.Context, id string, data
DataContext) error {
+ return MultiStartBundle(ctx, id, data, n.Out)
+}
+
+func (n *ReshuffleInput) ProcessElement(ctx context.Context, value *FullValue,
values ...ReStream) error {
+ n.b.Reset()
+ if err := EncodeWindowedValueHeader(n.wEnc, value.Windows,
value.Timestamp, &n.b); err != nil {
+ return err
+ }
+ if err := n.enc.Encode(value, &n.b); err != nil {
+ return errors.WithContextf(err, "encoding element %v with coder
%v", value, n.Coder)
+ }
+ n.ret = FullValue{Elm: n.r.Int(), Elm2: n.b.Bytes(), Timestamp:
value.Timestamp}
+ if err := n.Out.ProcessElement(ctx, &n.ret); err != nil {
+ return err
+ }
+ return nil
Review comment:
```suggestion
return n.Out.ProcessElement(ctx, &n.ret)
```
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Issue Time Tracking
-------------------
Worklog Id: (was: 408532)
Time Spent: 1h 50m (was: 1h 40m)
> Add a Reshuffle PTransform preventing fusion of the surrounding transforms
> --------------------------------------------------------------------------
>
> Key: BEAM-8292
> URL: https://issues.apache.org/jira/browse/BEAM-8292
> Project: Beam
> Issue Type: New Feature
> Components: sdk-go
> Reporter: John Patoch
> Assignee: Robert Burke
> Priority: Minor
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> Reshuffle is a PTransform that takes a PCollection<A> and shuffles the data
> to help increase parallelism.
> Reshuffle adds a temporary random key to each element, performs a
> GroupByKey, and finally removes the temporary key.
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