Struct Client

pub struct Client { /* private fields */ }

Implementations

impl Client

pub fn new(inner: SpannerClient<Channel>) -> Client

create new spanner client

pub async fn create_session( &mut self, req: CreateSessionRequest, retry: Option<RetrySetting>, ) -> Result<Response<Session>, Status>

create_session creates a new session. A session can be used to perform transactions that read and/or modify data in a Cloud Spanner database. Sessions are meant to be reused for many consecutive transactions.

Sessions can only execute one transaction at a time. To execute multiple concurrent read-write/write-only transactions, create multiple sessions. Note that standalone reads and queries use a transaction internally, and count toward the one transaction limit.

Active sessions use additional server resources, so it is a good idea to delete idle and unneeded sessions. Aside from explicit deletes, Cloud Spanner may delete sessions for which no operations are sent for more than an hour. If a session is deleted, requests to it return NOT_FOUND.

Idle sessions can be kept alive by sending a trivial SQL query periodically, e.g., “SELECT 1”.

pub async fn batch_create_sessions( &mut self, req: BatchCreateSessionsRequest, retry: Option<RetrySetting>, ) -> Result<Response<BatchCreateSessionsResponse>, Status>

batch_create_sessions creates multiple new sessions.

This API can be used to initialize a session cache on the clients. See https:///goo.gl/TgSFN2 (at https:///goo.gl/TgSFN2) for best practices on session cache management.

pub async fn get_session( &mut self, req: GetSessionRequest, retry: Option<RetrySetting>, ) -> Result<Response<Session>, Status>

get_session gets a session. Returns NOT_FOUND if the session does not exist. This is mainly useful for determining whether a session is still alive.

pub async fn list_sessions( &mut self, req: ListSessionsRequest, retry: Option<RetrySetting>, ) -> Result<Response<ListSessionsResponse>, Status>

list_sessions lists all sessions in a given database.

pub async fn delete_session( &mut self, req: DeleteSessionRequest, retry: Option<RetrySetting>, ) -> Result<Response<()>, Status>

delete_session ends a session, releasing server resources associated with it. This will asynchronously trigger cancellation of any operations that are running with this session.

pub async fn execute_sql( &mut self, req: ExecuteSqlRequest, retry: Option<RetrySetting>, ) -> Result<Response<ResultSet>, Status>

execute_sql executes an SQL statement, returning all results in a single reply. This method cannot be used to return a result set larger than 10 MiB; if the query yields more data than that, the query fails with a FAILED_PRECONDITION error.

Operations inside read-write transactions might return ABORTED. If this occurs, the application should restart the transaction from the beginning. See Transaction for more details.

Larger result sets can be fetched in streaming fashion by calling ExecuteStreamingSql instead.

pub async fn execute_streaming_sql( &mut self, req: ExecuteSqlRequest, retry: Option<RetrySetting>, ) -> Result<Response<Streaming<PartialResultSet>>, Status>

execute_streaming_sql like ExecuteSql, except returns the result set as a stream. Unlike ExecuteSql, there is no limit on the size of the returned result set. However, no individual row in the result set can exceed 100 MiB, and no column value can exceed 10 MiB.

pub async fn execute_batch_dml( &mut self, req: ExecuteBatchDmlRequest, retry: Option<RetrySetting>, ) -> Result<Response<ExecuteBatchDmlResponse>, Status>

execute_batch_dml executes a batch of SQL DML statements. This method allows many statements to be run with lower latency than submitting them sequentially with ExecuteSql.

Statements are executed in sequential order. A request can succeed even if a statement fails. The ExecuteBatchDmlResponse.status field in the response provides information about the statement that failed. Clients must inspect this field to determine whether an error occurred.

Execution stops after the first failed statement; the remaining statements are not executed.

pub async fn read( &mut self, req: ReadRequest, retry: Option<RetrySetting>, ) -> Result<Response<ResultSet>, Status>

read reads rows from the database using key lookups and scans, as a simple key/value style alternative to ExecuteSql. This method cannot be used to return a result set larger than 10 MiB; if the read matches more data than that, the read fails with a FAILED_PRECONDITION error.

Reads inside read-write transactions might return ABORTED. If this occurs, the application should restart the transaction from the beginning. See Transaction for more details.

Larger result sets can be yielded in streaming fashion by calling StreamingRead instead.

pub async fn streaming_read( &mut self, req: ReadRequest, retry: Option<RetrySetting>, ) -> Result<Response<Streaming<PartialResultSet>>, Status>

streaming_read like read, except returns the result set as a stream. Unlike read, there is no limit on the size of the returned result set. However, no individual row in the result set can exceed 100 MiB, and no column value can exceed 10 MiB.

pub async fn begin_transaction( &mut self, req: BeginTransactionRequest, retry: Option<RetrySetting>, ) -> Result<Response<Transaction>, Status>

BeginTransaction begins a new transaction. This step can often be skipped: Read, ExecuteSql and Commit can begin a new transaction as a side-effect.

pub async fn commit( &mut self, req: CommitRequest, retry: Option<RetrySetting>, ) -> Result<Response<CommitResponse>, Status>

Commit commits a transaction. The request includes the mutations to be applied to rows in the database.

Commit might return an ABORTED error. This can occur at any time; commonly, the cause is conflicts with concurrent transactions. However, it can also happen for a variety of other reasons. If Commit returns ABORTED, the caller should re-attempt the transaction from the beginning, re-using the same session.

On very rare occasions, Commit might return UNKNOWN. This can happen, for example, if the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost track of the transaction outcome and we recommend that you perform another read from the database to see the state of things as they are now.

pub async fn rollback( &mut self, req: RollbackRequest, retry: Option<RetrySetting>, ) -> Result<Response<()>, Status>

Rollback rolls back a transaction, releasing any locks it holds. It is a good idea to call this for any transaction that includes one or more Read or ExecuteSql requests and ultimately decides not to commit.

Rollback returns OK if it successfully aborts the transaction, the transaction was already aborted, or the transaction is not found. Rollback never returns ABORTED.

pub async fn partition_query( &mut self, req: PartitionQueryRequest, retry: Option<RetrySetting>, ) -> Result<Response<PartitionResponse>, Status>

PartitionQuery creates a set of partition tokens that can be used to execute a query operation in parallel. Each of the returned partition tokens can be used by ExecuteStreamingSql to specify a subset of the query result to read. The same session and read-only transaction must be used by the PartitionQueryRequest used to create the partition tokens and the ExecuteSqlRequests that use the partition tokens.

Partition tokens become invalid when the session used to create them is deleted, is idle for too long, begins a new transaction, or becomes too old. When any of these happen, it is not possible to resume the query, and the whole operation must be restarted from the beginning.

pub async fn partition_read( &mut self, req: PartitionReadRequest, retry: Option<RetrySetting>, ) -> Result<Response<PartitionResponse>, Status>

PartitionRead creates a set of partition tokens that can be used to execute a read operation in parallel. Each of the returned partition tokens can be used by StreamingRead to specify a subset of the read result to read. The same session and read-only transaction must be used by the PartitionReadRequest used to create the partition tokens and the ReadRequests that use the partition tokens. There are no ordering guarantees on rows returned among the returned partition tokens, or even within each individual StreamingRead call issued with a partition_token.

Partition tokens become invalid when the session used to create them is deleted, is idle for too long, begins a new transaction, or becomes too old. When any of these happen, it is not possible to resume the read, and the whole operation must be restarted from the beginning.

Trait Implementations

impl Clone for Client

fn clone(&self) -> Client

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.