github.com/pingcap/tiflow@v0.0.0-20240520035814-5bf52d54e205/cdc/sink/dmlsink/mq/dispatcher/partition/table.go (about)

     1  // Copyright 2022 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package partition
    15  
    16  import (
    17  	"sync"
    18  
    19  	"github.com/pingcap/tiflow/cdc/model"
    20  	"github.com/pingcap/tiflow/pkg/hash"
    21  )
    22  
    23  // TableDispatcher is a partition dispatcher which dispatches events
    24  // based on the schema and table name.
    25  type TableDispatcher struct {
    26  	hasher *hash.PositionInertia
    27  	lock   sync.Mutex
    28  }
    29  
    30  // NewTableDispatcher creates a TableDispatcher.
    31  func NewTableDispatcher() *TableDispatcher {
    32  	return &TableDispatcher{
    33  		hasher: hash.NewPositionInertia(),
    34  	}
    35  }
    36  
    37  // DispatchRowChangedEvent returns the target partition to which
    38  // a row changed event should be dispatched.
    39  func (t *TableDispatcher) DispatchRowChangedEvent(row *model.RowChangedEvent, partitionNum int32) (int32, string, error) {
    40  	t.lock.Lock()
    41  	defer t.lock.Unlock()
    42  	t.hasher.Reset()
    43  	// distribute partition by table
    44  	t.hasher.Write([]byte(row.TableInfo.GetSchemaName()), []byte(row.TableInfo.GetTableName()))
    45  	return int32(t.hasher.Sum32() % uint32(partitionNum)), row.TableInfo.TableName.String(), nil
    46  }