tech.ydb.query

Interface QuerySession

All Superinterfaces:

AutoCloseable

@ExperimentalApi(value="QueryService is experimental and API may change without notice")
public interface QuerySession
extends AutoCloseable

Sessions are basic primitives for communicating with YDB Query Service. The are similar to connections for classic relational DBs. Sessions serve three main purposes:

1. Provide a flow control for DB requests with limited number of active channels.
2. Distribute load evenly across multiple DB nodes.
3. Store state for volatile stateful operations, such as short-living transactions.

Author:

Aleksandr Gorshenin

Method Summary

Modifier and Type	Method and Description
default CompletableFuture<Result<QueryTransaction>>	beginTransaction(tech.ydb.common.transaction.TxMode txMode) Create and start a new active QueryTransaction.
CompletableFuture<Result<QueryTransaction>>	beginTransaction(tech.ydb.common.transaction.TxMode txMode, BeginTransactionSettings settings) Create and start a new active QueryTransaction.
void	close()
QueryTransaction	createNewTransaction(tech.ydb.common.transaction.TxMode txMode) Create a new not active QueryTransaction.
default QueryStream	createQuery(String query, tech.ydb.common.transaction.TxMode tx) Create QueryStream for executing query with specified TxMode.
default QueryStream	createQuery(String query, tech.ydb.common.transaction.TxMode tx, Params params) Create QueryStream for executing query with specified TxMode.
QueryStream	createQuery(String query, tech.ydb.common.transaction.TxMode tx, Params params, ExecuteQuerySettings settings) Create QueryStream for executing query with specified TxMode.
QueryTransaction	currentTransaction()
String	getId() Return the identifier of the session

Method Detail

getId

String getId()

Return the identifier of the session

Returns:

identifier of the session

currentTransaction

QueryTransaction currentTransaction()

Returns:

current QueryTransaction of the session

createNewTransaction

QueryTransaction createNewTransaction(tech.ydb.common.transaction.TxMode txMode)

Create a new not active QueryTransaction. This QueryTransaction will have no identifier and starts a transaction on server by execution any query

Parameters:

txMode - transaction mode

Returns:

new implicit transaction

beginTransaction

CompletableFuture<Result<QueryTransaction>> beginTransaction(tech.ydb.common.transaction.TxMode txMode,
                                                             BeginTransactionSettings settings)

Create and start a new active QueryTransaction. This method creates a transaction on the server and returns QueryTransaction which is ready to execute queries on this server transaction

Parameters:

txMode - transaction mode

settings - additional settings for request

Returns:

future with result of the transaction starting

createQuery

QueryStream createQuery(String query,
                        tech.ydb.common.transaction.TxMode tx,
                        Params params,
                        ExecuteQuerySettings settings)

Create QueryStream for executing query with specified TxMode. The query can contain DML, DDL and DCL statements. Supported mix of different statement types depends on the chosen transaction type.

Parameters:

query - text of query

tx - transaction mode

params - query parameters

settings - additional settings of query execution

Returns:

a ready to execute instance of QueryStream

close

void close()

Specified by:

close in interface AutoCloseable

createQuery

default QueryStream createQuery(String query,
                                tech.ydb.common.transaction.TxMode tx,
                                Params params)

Create QueryStream for executing query with specified TxMode. The query can contain DML, DDL and DCL statements. Supported mix of different statement types depends on the chosen transaction type.

Parameters:

query - text of query

tx - transaction mode

params - query parameters

Returns:

a ready to execute instance of QueryStream

createQuery

default QueryStream createQuery(String query,
                                tech.ydb.common.transaction.TxMode tx)

Create QueryStream for executing query with specified TxMode. The query can contain DML, DDL and DCL statements. Supported mix of different statement types depends on the chosen transaction type.

Parameters:

query - text of query

tx - transaction mode

Returns:

a ready to execute instance of QueryStream

beginTransaction

default CompletableFuture<Result<QueryTransaction>> beginTransaction(tech.ydb.common.transaction.TxMode txMode)

Create and start a new active QueryTransaction. This method creates a transaction on the server and returns QueryTransaction which is ready to execute queries on this server transaction

Parameters:

txMode - transaction mode

Returns:

future with result of the transaction starting