Random choice

    Note

    The article is being updated.

    The YDB SDK uses the random_choice algorithm by default.

    Below are examples of the code for forced setting of the "random choice" balancing algorithm in different YDB SDKs.

    package main
    
    import (
      "context"
      "os"
    
      "github.com/ydb-platform/ydb-go-sdk/v3"
      "github.com/ydb-platform/ydb-go-sdk/v3/balancers"
    )
    
    func main() {
      ctx, cancel := context.WithCancel(context.Background())
      defer cancel()
      db, err := ydb.Open(ctx,
        os.Getenv("YDB_CONNECTION_STRING"),
        ydb.WithBalancer(
          balancers.RandomChoice(),
        ),
      )
      if err != nil {
        panic(err)
      }
      defer db.Close(ctx)
      ...
    }
    

    Client load balancing in the YDB database/sql driver is performed only when establishing a new connection (in database/sql terms), which is a YDB session on a specific node. Once the session is created, all queries in this session are passed to the node where the session was created. Queries in the same YDB session are not balanced between different YDB nodes.

    Example of the code for setting the "random choice" balancing algorithm:

    package main
    
    import (
      "context"
      "database/sql"
      "os"
    
      "github.com/ydb-platform/ydb-go-sdk/v3"
      "github.com/ydb-platform/ydb-go-sdk/v3/balancers"
    )
    
    func main() {
      ctx, cancel := context.WithCancel(context.Background())
      defer cancel()
      nativeDriver, err := ydb.Open(ctx,
        os.Getenv("YDB_CONNECTION_STRING"),
        ydb.WithBalancer(
          balancers.RandomChoice(),
        ),
      )
      if err != nil {
        panic(err)
      }
      defer nativeDriver.Close(ctx)
    
      connector, err := ydb.Connector(nativeDriver)
      if err != nil {
        panic(err)
      }
    
      db := sql.OpenDB(connector)
      defer db.Close()
      ...
    }