Question

我正在使用mongo-go-driver 0.0.18来构建由“ NewUpdateManyModel”和几个“ NewInsertOneModel”组成的批量写入。我的mongo服务器是带有副本集的Atlas M10。我构建了一些goroutines来测试事务是否是原子的，结果表明每个批量写入都不是原子的，它们会相互干扰。我想知道mongo-go-driver是否支持多文档交易？

func insertUpdateQuery(counter int, col *mongo.Collection, group *sync.WaitGroup){
var operations []mongo.WriteModel
var items = []item{}
items=append(items,item{"Name":strconv.Itoa(counter),"Description":"latest one"})

for _,v := range items{
    operations = append(operations, mongo.NewInsertOneModel().Document(v))
}

updateOperation := mongo.NewUpdateManyModel()
updateOperation.Filter(bson.D{
    {"Name", bson.D{
        {"$ne", strconv.Itoa(counter)},
    }},
})
updateOperation.Update(bson.D{
    {"$set", bson.D{
        {"Description", strconv.Itoa(counter)},
    }},
},)
operations = append(operations,updateOperation)

bulkOps:=options.BulkWrite()
result, err := col.BulkWrite(
    context.Background(),
    operations,
    bulkOps,
)
if err != nil{
    fmt.Println("err:",err)
}else{
    fmt.Printf("IU: %+v \n",result)
}

group.Done()

}


func retrieveQuery(group *sync.WaitGroup, col *mongo.Collection){
var results []item
qctx:=context.Background()
qctx, c := context.WithTimeout(qctx, 10*time.Second)
defer c()
cur, err := col.Find(qctx, nil)
if err != nil {
    log.Fatal(err)
}
defer cur.Close(context.Background())
res := item{}
for cur.Next(context.Background()) {
    err := cur.Decode(&res)
    if err != nil {
        log.Println(err)
    }else {
        results=append(results,res)
    }
}
if err := cur.Err(); err != nil {
    log.Println(err)
}

fmt.Println("res:",results)

group.Done()
}



func main()  {
ctx := context.Background()
ctx, cancel := context.WithTimeout(ctx,10*time.Second)
defer cancel()

uri := "..."
client, err := mongo.NewClient(uri)
if err != nil {
    fmt.Printf("todo: couldn't connect to mongo: %v", err)
}
defer cancel()
err = client.Connect(ctx)
if err != nil {
    fmt.Printf("todo: mongo client couldn't connect with background context: %v", err)
}
col:=client.Database("jistest").Collection("Rules")

wg :=&sync.WaitGroup{}

for i:=0; i<100; i++{
    wg.Add(2)
    go insertUpdateQuery(i,col,wg)
    go retrieveQuery(wg,col)

}
wg.Wait()
fmt.Println("All Done!")
}

Answer 1

我想知道mongo-go-driver是否支持多文档交易？

mongo-go-driver从v0.0.12开始支持多文档交易（当前为beta版本0.1.0）。

MongoDB multi-document transactions与会话相关联。也就是说，您开始一个会话的事务。使用任何MongoDB官方支持的驱动程序时，必须将session传递给事务中的每个操作。

您的示例似乎没有利用会话或事务。 mongo-go-driver（v0.1.0）中的多文档事务示例如下：

client, err := mongo.NewClient("<MONGODB URI>")
if err != nil { return err }
ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
err = client.Connect(ctx)
if err != nil { return err }

session, err := client.StartSession()
database := client.Database("databaseName")
collection := database.Collection("collectionName")

err = mongo.WithSession(ctx, session, func(sctx mongo.SessionContext) error {
        // Start a transaction in the session 
        sctx.StartTransaction()

        var operations []mongo.WriteModel
        // Create an insert one operation
        operations = append(operations,
                            mongo.NewInsertOneModel().Document(
                            bson.D{{"Name", counter}, 
                                   {"Description", "latest"}}))

        // Create an update many operation
        updateOperation := mongo.NewUpdateManyModel()
        updateOperation.Filter(bson.D{{"Name", bson.D{
            {"$ne", counter},
        }}})
        updateOperation.Update(bson.D{
            {"$set", bson.D{
                {"Description", counter},
            }},
        })
        operations = append(operations, updateOperation)

        // Execute bulkWrite operation in a transactional session.
        _, err := collection.BulkWrite(sctx, operations)
        if err != nil {
            fmt.Println(err)
            return err
        }
        // Committing transaction
        session.CommitTransaction(sctx)
        return nil
})
session.EndSession(ctx)

另请参阅Transactions and Retryable Writes，以获取重试交易的示例。

我构建了一些goroutines来测试交易是否是原子的

请注意流程的执行方式。例如，根据赛车状况，您可能会获得最新的性能来覆盖结果。即

transaction 1 finished 
transaction 2 finished 
transaction 3 and transaction 4 conflict 
transaction 5 finished
...

bulkwrite不支持使用mongo-go-driver进行多文档交易

1 个答案: