Package google.spanner.v1

Index

• Spanner (interface)
• BatchCreateSessionsRequest (message)
• BatchCreateSessionsResponse (message)
• BatchWriteRequest (message)
• BatchWriteRequest.MutationGroup (message)
• BatchWriteResponse (message)
• BeginTransactionRequest (message)
• CommitRequest (message)
• CommitResponse (message)
• CommitResponse.CommitStats (message)
• CreateSessionRequest (message)
• DeleteSessionRequest (message)
• DirectedReadOptions (message)
• DirectedReadOptions.ExcludeReplicas (message)
• DirectedReadOptions.IncludeReplicas (message)
• DirectedReadOptions.ReplicaSelection (message)
• DirectedReadOptions.ReplicaSelection.Type (enum)
• ExecuteBatchDmlRequest (message)
• ExecuteBatchDmlRequest.Statement (message)
• ExecuteBatchDmlResponse (message)
• ExecuteSqlRequest (message)
• ExecuteSqlRequest.QueryMode (enum)
• ExecuteSqlRequest.QueryOptions (message)
• GetSessionRequest (message)
• KeyRange (message)
• KeySet (message)
• ListSessionsRequest (message)
• ListSessionsResponse (message)
• Mutation (message)
• Mutation.Delete (message)
• Mutation.Write (message)
• PartialResultSet (message)
• Partition (message)
• PartitionOptions (message)
• PartitionQueryRequest (message)
• PartitionReadRequest (message)
• PartitionResponse (message)
• PlanNode (message)
• PlanNode.ChildLink (message)
• PlanNode.Kind (enum)
• PlanNode.ShortRepresentation (message)
• QueryPlan (message)
• ReadRequest (message)
• RequestOptions (message)
• RequestOptions.Priority (enum)
• ResultSet (message)
• ResultSetMetadata (message)
• ResultSetStats (message)
• RollbackRequest (message)
• Session (message)
• StructType (message)
• StructType.Field (message)
• Transaction (message)
• TransactionOptions (message)
• TransactionOptions.PartitionedDml (message)
• TransactionOptions.ReadOnly (message)
• TransactionOptions.ReadWrite (message)
• TransactionSelector (message)
• Type (message)
• TypeAnnotationCode (enum)
• TypeCode (enum)

Spanner

Cloud Spanner API

The Cloud Spanner API can be used to manage sessions and execute transactions on data stored in Cloud Spanner databases.

BatchCreateSessions

rpc BatchCreateSessions(BatchCreateSessionsRequest) returns (BatchCreateSessionsResponse) Creates multiple new sessions. This API can be used to initialize a session cache on the clients. See https://goo.gl/TgSFN2 for best practices on session cache management. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

BatchWrite

rpc BatchWrite(BatchWriteRequest) returns (BatchWriteResponse) Batches the supplied mutation groups in a collection of efficient transactions. All mutations in a group are committed atomically. However, mutations across groups can be committed non-atomically in an unspecified order and thus, they must be independent of each other. Partial failure is possible, i.e., some groups may have been committed successfully, while some may have failed. The results of individual batches are streamed into the response as the batches are applied. BatchWrite requests are not replay protected, meaning that each mutation group may be applied more than once. Replays of non-idempotent mutations may have undesirable effects. For example, replays of an insert mutation may produce an already exists error or if you use generated or commit timestamp-based keys, it may result in additional rows being added to the mutation's table. We recommend structuring your mutation groups to be idempotent to avoid this issue. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

BeginTransaction

rpc BeginTransaction(BeginTransactionRequest) returns (Transaction) Begins a new transaction. This step can often be skipped: Read, ExecuteSql and Commit can begin a new transaction as a side-effect. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

Commit

rpc Commit(CommitRequest) returns (CommitResponse) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

CreateSession

rpc CreateSession(CreateSessionRequest) returns (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". Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

DeleteSession

rpc DeleteSession(DeleteSessionRequest) returns (Empty) Ends a session, releasing server resources associated with it. This will asynchronously trigger cancellation of any operations that are running with this session. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

ExecuteBatchDml

rpc ExecuteBatchDml(ExecuteBatchDmlRequest) returns (ExecuteBatchDmlResponse) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

ExecuteSql

rpc ExecuteSql(ExecuteSqlRequest) returns (ResultSet) 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. The query string can be SQL or Graph Query Language (GQL). Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

ExecuteStreamingSql

rpc ExecuteStreamingSql(ExecuteSqlRequest) returns (PartialResultSet) 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. The query string can be SQL or Graph Query Language (GQL). Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

GetSession

rpc GetSession(GetSessionRequest) returns (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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

ListSessions
rpc ListSessions(ListSessionsRequest) returns (ListSessionsResponse) Lists all sessions in a given database. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

PartitionQuery

rpc PartitionQuery(PartitionQueryRequest) returns (PartitionResponse) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

PartitionRead

rpc PartitionRead(PartitionReadRequest) returns (PartitionResponse) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

Read

rpc Read(ReadRequest) returns (ResultSet) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

Rollback

rpc Rollback(RollbackRequest) returns (Empty) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

StreamingRead

rpc StreamingRead(ReadRequest) returns (PartialResultSet) 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. Authorization scopes Requires one of the following OAuth scopes: https://www.googleapis.com/auth/spanner.data https://www.googleapis.com/auth/cloud-platform For more information, see the Authentication Overview.

BatchCreateSessionsRequest

The request for BatchCreateSessions.

Fields
database	string Required. The database in which the new sessions are created. Authorization requires the following IAM permission on the specified resource database: spanner.sessions.create
session_template	Session Parameters to be applied to each created session.
session_count	int32 Required. The number of sessions to be created in this batch call. The API may return fewer than the requested number of sessions. If a specific number of sessions are desired, the client can make additional calls to BatchCreateSessions (adjusting session_count as necessary).

BatchCreateSessionsResponse

The response for BatchCreateSessions.

Fields
session[]	Session The freshly created sessions.

BatchWriteRequest

The request for BatchWrite.

Fields
session	string Required. The session in which the batch request is to be run. Authorization requires the following IAM permission on the specified resource session: spanner.databases.write
request_options	RequestOptions Common options for this request.
mutation_groups[]	MutationGroup Required. The groups of mutations to be applied.

MutationGroup

A group of mutations to be committed together. Related mutations should be placed in a group. For example, two mutations inserting rows with the same primary key prefix in both parent and child tables are related.

Fields
mutations[]	Mutation Required. The mutations in this group.

BatchWriteResponse

The result of applying a batch of mutations.

Fields
indexes[]	int32 The mutation groups applied in this batch. The values index into the mutation_groups field in the corresponding BatchWriteRequest.
status	Status An OK status indicates success. Any other status indicates a failure.
commit_timestamp	Timestamp The commit timestamp of the transaction that applied this batch. Present if status is OK, absent otherwise.

BeginTransactionRequest

The request for BeginTransaction.

Fields
session	string Required. The session in which the transaction runs. Authorization requires one or more of the following IAM permissions on the specified resource session: spanner.databases.beginReadOnlyTransaction spanner.databases.beginOrRollbackReadWriteTransaction
options	TransactionOptions Required. Options for the new transaction.
request_options	RequestOptions Common options for this request. Priority is ignored for this request. Setting the priority in this request_options struct will not do anything. To set the priority for a transaction, set it on the reads and writes that are part of this transaction instead.

CommitRequest

The request for Commit.

Fields
session	string Required. The session in which the transaction to be committed is running. Authorization requires the following IAM permission on the specified resource session: spanner.databases.write
mutations[]	Mutation The mutations to be executed when this transaction commits. All mutations are applied atomically, in the order they appear in this list.
return_commit_stats	bool If true, then statistics related to the transaction will be included in the CommitResponse. Default value is false.
max_commit_delay	Duration Optional. The amount of latency this request is configured to incur in order to improve throughput. If this field is not set, Spanner assumes requests are relatively latency sensitive and automatically determines an appropriate delay time. You can specify a commit delay value between 0 and 500 ms.
request_options	RequestOptions Common options for this request.
Union field transaction. Required. The transaction in which to commit. transaction can be only one of the following:
transaction_id	bytes Commit a previously-started transaction.
single_use_transaction	TransactionOptions Execute mutations in a temporary transaction. Note that unlike commit of a previously-started transaction, commit with a temporary transaction is non-idempotent. That is, if the CommitRequest is sent to Cloud Spanner more than once (for instance, due to retries in the application, or in the transport library), it is possible that the mutations are executed more than once. If this is undesirable, use BeginTransaction and Commit instead.

CommitResponse

The response for Commit.

Fields
commit_timestamp	Timestamp The Cloud Spanner timestamp at which the transaction committed.
commit_stats	CommitStats The statistics about this Commit. Not returned by default. For more information, see CommitRequest.return_commit_stats.

CommitStats

Additional statistics about a commit.

Fields
mutation_count	int64 The total number of mutations for the transaction. Knowing the mutation_count value can help you maximize the number of mutations in a transaction and minimize the number of API round trips. You can also monitor this value to prevent transactions from exceeding the system limit. If the number of mutations exceeds the limit, the server returns INVALID_ARGUMENT.

CreateSessionRequest

The request for CreateSession.

Fields
database	string Required. The database in which the new session is created. Authorization requires the following IAM permission on the specified resource database: spanner.sessions.create
session	Session Required. The session to create.

DeleteSessionRequest

The request for DeleteSession.

Fields
name	string Required. The name of the session to delete. Authorization requires the following IAM permission on the specified resource name: spanner.sessions.delete

DirectedReadOptions

The DirectedReadOptions can be used to indicate which replicas or regions should be used for non-transactional reads or queries.

DirectedReadOptions may only be specified for a read-only transaction, otherwise the API will return an INVALID_ARGUMENT error.

Fields
Union field replicas. Required. At most one of either include_replicas or exclude_replicas should be present in the message. replicas can be only one of the following:
include_replicas	IncludeReplicas Include_replicas indicates the order of replicas (as they appear in this list) to process the request. If auto_failover_disabled is set to true and all replicas are exhausted without finding a healthy replica, Spanner will wait for a replica in the list to become available, requests may fail due to DEADLINE_EXCEEDED errors.
exclude_replicas	ExcludeReplicas Exclude_replicas indicates that specified replicas should be excluded from serving requests. Spanner will not route requests to the replicas in this list.

ExcludeReplicas

An ExcludeReplicas contains a repeated set of ReplicaSelection that should be excluded from serving requests.

Fields
replica_selections[]	ReplicaSelection The directed read replica selector.

IncludeReplicas

An IncludeReplicas contains a repeated set of ReplicaSelection which indicates the order in which replicas should be considered.

Fields
replica_selections[]	ReplicaSelection The directed read replica selector.
auto_failover_disabled	bool If true, Spanner will not route requests to a replica outside the include_replicas list when all of the specified replicas are unavailable or unhealthy. Default value is false.

ReplicaSelection

The directed read replica selector. Callers must provide one or more of the following fields for replica selection:

• location - The location must be one of the regions within the multi-region configuration of your database.
• type - The type of the replica.

Some examples of using replica_selectors are:

• location:us-east1 --> The "us-east1" replica(s) of any available type will be used to process the request.
• type:READ_ONLY --> The "READ_ONLY" type replica(s) in nearest available location will be used to process the request.
• location:us-east1 type:READ_ONLY --> The "READ_ONLY" type replica(s) in location "us-east1" will be used to process the request.

Fields
location	string The location or region of the serving requests, e.g. "us-east1".
type	Type The type of replica.

Type

Indicates the type of replica.

Enums
TYPE_UNSPECIFIED	Not specified.
READ_WRITE	Read-write replicas support both reads and writes.
READ_ONLY	Read-only replicas only support reads (not writes).

ExecuteBatchDmlRequest

The request for ExecuteBatchDml.

Fields
session	string Required. The session in which the DML statements should be performed. Authorization requires the following IAM permission on the specified resource session: spanner.databases.write
transaction	TransactionSelector Required. The transaction to use. Must be a read-write transaction. To protect against replays, single-use transactions are not supported. The caller must either supply an existing transaction ID or begin a new transaction.
statements[]	Statement Required. The list of statements to execute in this batch. Statements are executed serially, such that the effects of statement i are visible to statement i+1. Each statement must be a DML statement. Execution stops at the first failed statement; the remaining statements are not executed. Callers must provide at least one statement.
seqno	int64 Required. A per-transaction sequence number used to identify this request. This field makes each request idempotent such that if the request is received multiple times, at most one will succeed. The sequence number must be monotonically increasing within the transaction. If a request arrives for the first time with an out-of-order sequence number, the transaction may be aborted. Replays of previously handled requests will yield the same response as the first execution.
request_options	RequestOptions Common options for this request.

Statement

A single DML statement.

Fields
sql	string Required. The DML string.
params	Struct Parameter names and values that bind to placeholders in the DML string. A parameter placeholder consists of the @ character followed by the parameter name (for example, @firstName). Parameter names can contain letters, numbers, and underscores. Parameters can appear anywhere that a literal value is expected. The same parameter name can be used more than once, for example: "WHERE id > @msg_id AND id < @msg_id + 100" It is an error to execute a SQL statement with unbound parameters.
param_types	map<string, Type> It is not always possible for Cloud Spanner to infer the right SQL type from a JSON value. For example, values of type BYTES and values of type STRING both appear in params as JSON strings. In these cases, param_types can be used to specify the exact SQL type for some or all of the SQL statement parameters. See the definition of Type for more information about SQL types.

ExecuteBatchDmlResponse

The response for ExecuteBatchDml. Contains a list of ResultSet messages, one for each DML statement that has successfully executed, in the same order as the statements in the request. If a statement fails, the status in the response body identifies the cause of the failure.

To check for DML statements that failed, use the following approach:

1. Check the status in the response message. The google.rpc.Code enum value OK indicates that all statements were executed successfully.
2. If the status was not OK, check the number of result sets in the response. If the response contains N ResultSet messages, then statement N+1 in the request failed.

Example 1:

• Request: 5 DML statements, all executed successfully.
• Response: 5 ResultSet messages, with the status OK.

Example 2:

• Request: 5 DML statements. The third statement has a syntax error.
• Response: 2 ResultSet messages, and a syntax error (INVALID_ARGUMENT) status. The number of ResultSet messages indicates that the third statement failed, and the fourth and fifth statements were not executed.

Fields
result_sets[]	ResultSet One ResultSet for each statement in the request that ran successfully, in the same order as the statements in the request. Each ResultSet does not contain any rows. The ResultSetStats in each ResultSet contain the number of rows modified by the statement. Only the first ResultSet in the response contains valid ResultSetMetadata.
status	Status If all DML statements are executed successfully, the status is OK. Otherwise, the error status of the first failed statement.

ExecuteSqlRequest

The request for ExecuteSql and ExecuteStreamingSql.

Fields
session	string Required. The session in which the SQL query should be performed. Authorization requires the following IAM permission on the specified resource session: spanner.databases.select
transaction	TransactionSelector The transaction to use. For queries, if none is provided, the default is a temporary read-only transaction with strong concurrency. Standard DML statements require a read-write transaction. To protect against replays, single-use transactions are not supported. The caller must either supply an existing transaction ID or begin a new transaction. Partitioned DML requires an existing Partitioned DML transaction ID.
sql	string Required. The SQL string.
params	Struct Parameter names and values that bind to placeholders in the SQL string. A parameter placeholder consists of the @ character followed by the parameter name (for example, @firstName). Parameter names must conform to the naming requirements of identifiers as specified at https://cloud.google.com/spanner/docs/lexical#identifiers. Parameters can appear anywhere that a literal value is expected. The same parameter name can be used more than once, for example: "WHERE id > @msg_id AND id < @msg_id + 100" It is an error to execute a SQL statement with unbound parameters.
param_types	map<string, Type> It is not always possible for Cloud Spanner to infer the right SQL type from a JSON value. For example, values of type BYTES and values of type STRING both appear in params as JSON strings. In these cases, param_types can be used to specify the exact SQL type for some or all of the SQL statement parameters. See the definition of Type for more information about SQL types.
resume_token	bytes If this request is resuming a previously interrupted SQL statement execution, resume_token should be copied from the last PartialResultSet yielded before the interruption. Doing this enables the new SQL statement execution to resume where the last one left off. The rest of the request parameters must exactly match the request that yielded this token.
query_mode	QueryMode Used to control the amount of debugging information returned in ResultSetStats. If partition_token is set, query_mode can only be set to QueryMode.NORMAL.
partition_token	bytes If present, results will be restricted to the specified partition previously created using PartitionQuery(). There must be an exact match for the values of fields common to this message and the PartitionQueryRequest message used to create this partition_token.
seqno	int64 A per-transaction sequence number used to identify this request. This field makes each request idempotent such that if the request is received multiple times, at most one will succeed. The sequence number must be monotonically increasing within the transaction. If a request arrives for the first time with an out-of-order sequence number, the transaction may be aborted. Replays of previously handled requests will yield the same response as the first execution. Required for DML statements. Ignored for queries.
query_options	QueryOptions Query optimizer configuration to use for the given query.
request_options	RequestOptions Common options for this request.
directed_read_options	DirectedReadOptions Directed read options for this request.
data_boost_enabled	bool If this is for a partitioned query and this field is set to true, the request is executed with Spanner Data Boost independent compute resources. If the field is set to true but the request does not set partition_token, the API returns an INVALID_ARGUMENT error.

QueryMode

Mode in which the statement must be processed.

Enums
NORMAL	The default mode. Only the statement results are returned.
PLAN	This mode returns only the query plan, without any results or execution statistics information.
PROFILE	This mode returns the query plan, overall execution statistics, operator level execution statistics along with the results. This has a performance overhead compared to the other modes. It is not recommended to use this mode for production traffic.

QueryOptions

Query optimizer configuration.

Fields
optimizer_version	string An option to control the selection of optimizer version. This parameter allows individual queries to pick different query optimizer versions. Specifying latest as a value instructs Cloud Spanner to use the latest supported query optimizer version. If not specified, Cloud Spanner uses the optimizer version set at the database level options. Any other positive integer (from the list of supported optimizer versions) overrides the default optimizer version for query execution. The list of supported optimizer versions can be queried from SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement with an invalid optimizer version fails with an INVALID_ARGUMENT error. See https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer for more information on managing the query optimizer. The optimizer_version statement hint has precedence over this setting.
optimizer_statistics_package	string An option to control the selection of optimizer statistics package. This parameter allows individual queries to use a different query optimizer statistics package. Specifying latest as a value instructs Cloud Spanner to use the latest generated statistics package. If not specified, Cloud Spanner uses the statistics package set at the database level options, or the latest package if the database option is not set. The statistics package requested by the query has to be exempt from garbage collection. This can be achieved with the following DDL statement: ALTER STATISTICS <package_name> SET OPTIONS (allow_gc=false) The list of available statistics packages can be queried from INFORMATION_SCHEMA.SPANNER_STATISTICS. Executing a SQL statement with an invalid optimizer statistics package or with a statistics package that allows garbage collection fails with an INVALID_ARGUMENT error.

GetSessionRequest

The request for GetSession.

Fields
name	string Required. The name of the session to retrieve. Authorization requires the following IAM permission on the specified resource name: spanner.sessions.get

KeyRange

KeyRange represents a range of rows in a table or index.

A range has a start key and an end key. These keys can be open or closed, indicating if the range includes rows with that key.

Keys are represented by lists, where the ith value in the list corresponds to the ith component of the table or index primary key. Individual values are encoded as described here.

For example, consider the following table definition:

CREATE TABLE UserEvents (
  UserName STRING(MAX),
  EventDate STRING(10)
) PRIMARY KEY(UserName, EventDate);

The following keys name rows in this table:

["Bob", "2014-09-23"]
["Alfred", "2015-06-12"]

Since the UserEvents table's PRIMARY KEY clause names two columns, each UserEvents key has two elements; the first is the UserName, and the second is the EventDate.

Key ranges with multiple components are interpreted lexicographically by component using the table or index key's declared sort order. For example, the following range returns all events for user "Bob" that occurred in the year 2015:

"start_closed": ["Bob", "2015-01-01"]
"end_closed": ["Bob", "2015-12-31"]

Start and end keys can omit trailing key components. This affects the inclusion and exclusion of rows that exactly match the provided key components: if the key is closed, then rows that exactly match the provided components are included; if the key is open, then rows that exactly match are not included.

For example, the following range includes all events for "Bob" that occurred during and after the year 2000:

"start_closed": ["Bob", "2000-01-01"]
"end_closed": ["Bob"]

The next example retrieves all events for "Bob":

"start_closed": ["Bob"]
"end_closed": ["Bob"]

To retrieve events before the year 2000:

"start_closed": ["Bob"]
"end_open": ["Bob", "2000-01-01"]

The following range includes all rows in the table:

"start_closed": []
"end_closed": []

This range returns all users whose UserName begins with any character from A to C:

"start_closed": ["A"]
"end_open": ["D"]

This range returns all users whose UserName begins with B:

"start_closed": ["B"]
"end_open": ["C"]

Key ranges honor column sort order. For example, suppose a table is defined as follows:

CREATE TABLE DescendingSortedTable {
  Key INT64,
  ...
) PRIMARY KEY(Key DESC);

The following range retrieves all rows with key values between 1 and 100 inclusive:

"start_closed": ["100"]
"end_closed": ["1"]

Note that 100 is passed as the start, and 1 is passed as the end, because Key is a descending column in the schema.

Fields
Union field start_key_type. The start key must be provided. It can be either closed or open. start_key_type can be only one of the following:
start_closed	ListValue If the start is closed, then the range includes all rows whose first len(start_closed) key columns exactly match start_closed.
start_open	ListValue If the start is open, then the range excludes rows whose first len(start_open) key columns exactly match start_open.
Union field end_key_type. The end key must be provided. It can be either closed or open. end_key_type can be only one of the following:
end_closed	ListValue If the end is closed, then the range includes all rows whose first len(end_closed) key columns exactly match end_closed.
end_open	ListValue If the end is open, then the range excludes rows whose first len(end_open) key columns exactly match end_open.

KeySet

KeySet defines a collection of Cloud Spanner keys and/or key ranges. All the keys are expected to be in the same table or index. The keys need not be sorted in any particular way.

If the same key is specified multiple times in the set (for example if two ranges, two keys, or a key and a range overlap), Cloud Spanner behaves as if the key were only specified once.

Fields
keys[]	ListValue A list of specific keys. Entries in keys should have exactly as many elements as there are columns in the primary or index key with which this KeySet is used. Individual key values are encoded as described here.
ranges[]	KeyRange A list of key ranges. See KeyRange for more information about key range specifications.
all	bool For convenience all can be set to true to indicate that this KeySet matches all keys in the table or index. Note that any keys specified in keys or ranges are only yielded once.

ListSessionsRequest

The request for ListSessions.

Fields
database	string Required. The database in which to list sessions. Authorization requires the following IAM permission on the specified resource database: spanner.sessions.list
page_size	int32 Number of sessions to be returned in the response. If 0 or less, defaults to the server's maximum allowed page size.
page_token	string If non-empty, page_token should contain a next_page_token from a previous ListSessionsResponse.
filter	string An expression for filtering the results of the request. Filter rules are case insensitive. The fields eligible for filtering are: labels.key where key is the name of a label Some examples of using filters are: labels.env:* --> The session has the label "env". labels.env:dev --> The session has the label "env" and the value of the label contains the string "dev".

ListSessionsResponse

The response for ListSessions.

Fields
sessions[]	Session The list of requested sessions.
next_page_token	string next_page_token can be sent in a subsequent ListSessions call to fetch more of the matching sessions.

Mutation

A modification to one or more Cloud Spanner rows. Mutations can be applied to a Cloud Spanner database by sending them in a Commit call.

Fields
Union field operation. Required. The operation to perform. operation can be only one of the following:
insert	Write Insert new rows in a table. If any of the rows already exist, the write or transaction fails with error ALREADY_EXISTS.
update	Write Update existing rows in a table. If any of the rows does not already exist, the transaction fails with error NOT_FOUND.
insert_or_update	Write Like insert, except that if the row already exists, then its column values are overwritten with the ones provided. Any column values not explicitly written are preserved. When using insert_or_update, just as when using insert, all NOT NULL columns in the table must be given a value. This holds true even when the row already exists and will therefore actually be updated.
replace	Write Like insert, except that if the row already exists, it is deleted, and the column values provided are inserted instead. Unlike insert_or_update, this means any values not explicitly written become NULL. In an interleaved table, if you create the child table with the ON DELETE CASCADE annotation, then replacing a parent row also deletes the child rows. Otherwise, you must delete the child rows before you replace the parent row.
delete	Delete Delete rows from a table. Succeeds whether or not the named rows were present.

Delete

Arguments to delete operations.

Fields
table	string Required. The table whose rows will be deleted.
key_set	KeySet Required. The primary keys of the rows within table to delete. The primary keys must be specified in the order in which they appear in the PRIMARY KEY() clause of the table's equivalent DDL statement (the DDL statement used to create the table). Delete is idempotent. The transaction will succeed even if some or all rows do not exist.

Write

Arguments to insert, update, insert_or_update, and replace operations.

Fields
table	string Required. The table whose rows will be written.
columns[]	string The names of the columns in table to be written. The list of columns must contain enough columns to allow Cloud Spanner to derive values for all primary key columns in the row(s) to be modified.
values[]	ListValue The values to be written. values can contain more than one list of values. If it does, then multiple rows are written, one for each entry in values. Each list in values must have exactly as many entries as there are entries in columns above. Sending multiple lists is equivalent to sending multiple Mutations, each containing one values entry and repeating table and columns. Individual values in each list are encoded as described here.

PartialResultSet

Partial results from a streaming read or SQL query. Streaming reads and SQL queries better tolerate large result sets, large rows, and large values, but are a little trickier to consume.

Fields
metadata	ResultSetMetadata Metadata about the result set, such as row type information. Only present in the first response.
values[]	Value A streamed result set consists of a stream of values, which might be split into many PartialResultSet messages to accommodate large rows and/or large values. Every N complete values defines a row, where N is equal to the number of entries in metadata.row_type.fields. Most values are encoded based on type as described here. It is possible that the last value in values is "chunked", meaning that the rest of the value is sent in subsequent PartialResultSet(s). This is denoted by the chunked_value field. Two or more chunked values can be merged to form a complete value as follows: bool/number/null: cannot be chunked string: concatenate the strings list: concatenate the lists. If the last element in a list is a string, list, or object, merge it with the first element in the next list by applying these rules recursively. object: concatenate the (field name, field value) pairs. If a field name is duplicated, then apply these rules recursively to merge the field values. Some examples of merging: # Strings are concatenated. "foo", "bar" => "foobar" # Lists of non-strings are concatenated. [2, 3], [4] => [2, 3, 4] # Lists are concatenated, but the last and first elements are merged # because they are strings. ["a", "b"], ["c", "d"] => ["a", "bc", "d"] # Lists are concatenated, but the last and first elements are merged # because they are lists. Recursively, the last and first elements # of the inner lists are merged because they are strings. ["a", ["b", "c"]], [["d"], "e"] => ["a", ["b", "cd"], "e"] # Non-overlapping object fields are combined. {"a": "1"}, {"b": "2"} => {"a": "1", "b": 2"} # Overlapping object fields are merged. {"a": "1"}, {"a": "2"} => {"a": "12"} # Examples of merging objects containing lists of strings. {"a": ["1"]}, {"a": ["2"]} => {"a": ["12"]} For a more complete example, suppose a streaming SQL query is yielding a result set whose rows contain a single string field. The following PartialResultSets might be yielded: { "metadata": { ... } "values": ["Hello", "W"] "chunked_value": true "resume_token": "Af65..." } { "values": ["orl"] "chunked_value": true } { "values": ["d"] "resume_token": "Zx1B..." } This sequence of PartialResultSets encodes two rows, one containing the field value "Hello", and a second containing the field value "World" = "W" + "orl" + "d". Not all PartialResultSets contain a resume_token. Execution can only be resumed from a previously yielded resume_token. For the above sequence of PartialResultSets, resuming the query with "resume_token": "Af65..." will yield results from the PartialResultSet with value ["orl"].
chunked_value	bool If true, then the final value in values is chunked, and must be combined with more values from subsequent PartialResultSets to obtain a complete field value.
resume_token	bytes Streaming calls might be interrupted for a variety of reasons, such as TCP connection loss. If this occurs, the stream of results can be resumed by re-sending the original request and including resume_token. Note that executing any other transaction in the same session invalidates the token.
stats	ResultSetStats Query plan and execution statistics for the statement that produced this streaming result set. These can be requested by setting ExecuteSqlRequest.query_mode and are sent only once with the last response in the stream. This field will also be present in the last response for DML statements.

Partition

Information returned for each partition returned in a PartitionResponse.

Fields
partition_token	bytes This token can be passed to Read, StreamingRead, ExecuteSql, or ExecuteStreamingSql requests to restrict the results to those identified by this partition token.

PartitionOptions

Options for a PartitionQueryRequest and PartitionReadRequest.

Fields
partition_size_bytes	int64 Note: This hint is currently ignored by PartitionQuery and PartitionRead requests. The desired data size for each partition generated. The default for this option is currently 1 GiB. This is only a hint. The actual size of each partition may be smaller or larger than this size request.
max_partitions	int64 Note: This hint is currently ignored by PartitionQuery and PartitionRead requests. The desired maximum number of partitions to return. For example, this may be set to the number of workers available. The default for this option is currently 10,000. The maximum value is currently 200,000. This is only a hint. The actual number of partitions returned may be smaller or larger than this maximum count request.

PartitionQueryRequest

The request for PartitionQuery

Fields
session	string Required. The session used to create the partitions. Authorization requires the following IAM permission on the specified resource session: spanner.databases.partitionQuery
transaction	TransactionSelector Read only snapshot transactions are supported, read/write and single use transactions are not.
sql	string Required. The query request to generate partitions for. The request fails if the query is not root partitionable. For a query to be root partitionable, it needs to satisfy a few conditions. For example, if the query execution plan contains a distributed union operator, then it must be the first operator in the plan. For more information about other conditions, see Read data in parallel. The query request must not contain DML commands, such as INSERT, UPDATE, or DELETE. Use ExecuteStreamingSql with a PartitionedDml transaction for large, partition-friendly DML operations.
params	Struct Parameter names and values that bind to placeholders in the SQL string. A parameter placeholder consists of the @ character followed by the parameter name (for example, @firstName). Parameter names can contain letters, numbers, and underscores. Parameters can appear anywhere that a literal value is expected. The same parameter name can be used more than once, for example: "WHERE id > @msg_id AND id < @msg_id + 100" It is an error to execute a SQL statement with unbound parameters.
param_types	map<string, Type> It is not always possible for Cloud Spanner to infer the right SQL type from a JSON value. For example, values of type BYTES and values of type STRING both appear in params as JSON strings. In these cases, param_types can be used to specify the exact SQL type for some or all of the SQL query parameters. See the definition of Type for more information about SQL types.
partition_options	PartitionOptions Additional options that affect how many partitions are created.

PartitionReadRequest

The request for PartitionRead

Fields
session	string Required. The session used to create the partitions. Authorization requires the following IAM permission on the specified resource session: spanner.databases.partitionRead
transaction	TransactionSelector Read only snapshot transactions are supported, read/write and single use transactions are not.
table	string Required. The name of the table in the database to be read.
index	string If non-empty, the name of an index on table. This index is used instead of the table primary key when interpreting key_set and sorting result rows. See key_set for further information.
columns[]	string The columns of table to be returned for each row matching this request.
key_set	KeySet Required. key_set identifies the rows to be yielded. key_set names the primary keys of the rows in table to be yielded, unless index is present. If index is present, then key_set instead names index keys in index. It is not an error for the key_set to name rows that do not exist in the database. Read yields nothing for nonexistent rows.
partition_options	PartitionOptions Additional options that affect how many partitions are created.

PartitionResponse

The response for PartitionQuery or PartitionRead

Fields
partitions[]	Partition Partitions created by this request.
transaction	Transaction Transaction created by this request.

PlanNode

Node information for nodes appearing in a QueryPlan.plan_nodes.

Fields
index	int32 The PlanNode's index in node list.
kind	Kind Used to determine the type of node. May be needed for visualizing different kinds of nodes differently. For example, If the node is a SCALAR node, it will have a condensed representation which can be used to directly embed a description of the node in its parent.
display_name	string The display name for the node.
child_links[]	ChildLink List of child node indexes and their relationship to this parent.
short_representation	ShortRepresentation Condensed representation for SCALAR nodes.
metadata	Struct Attributes relevant to the node contained in a group of key-value pairs. For example, a Parameter Reference node could have the following information in its metadata: { "parameter_reference": "param1", "parameter_type": "array" }
execution_stats	Struct The execution statistics associated with the node, contained in a group of key-value pairs. Only present if the plan was returned as a result of a profile query. For example, number of executions, number of rows/time per execution etc.

ChildLink

Metadata associated with a parent-child relationship appearing in a PlanNode.

Fields
child_index	int32 The node to which the link points.
type	string The type of the link. For example, in Hash Joins this could be used to distinguish between the build child and the probe child, or in the case of the child being an output variable, to represent the tag associated with the output variable.
variable	string Only present if the child node is SCALAR and corresponds to an output variable of the parent node. The field carries the name of the output variable. For example, a TableScan operator that reads rows from a table will have child links to the SCALAR nodes representing the output variables created for each column that is read by the operator. The corresponding variable fields will be set to the variable names assigned to the columns.

Kind

The kind of PlanNode. Distinguishes between the two different kinds of nodes that can appear in a query plan.

Enums
KIND_UNSPECIFIED	Not specified.
RELATIONAL	Denotes a Relational operator node in the expression tree. Relational operators represent iterative processing of rows during query execution. For example, a TableScan operation that reads rows from a table.
SCALAR	Denotes a Scalar node in the expression tree. Scalar nodes represent non-iterable entities in the query plan. For example, constants or arithmetic operators appearing inside predicate expressions or references to column names.

ShortRepresentation

Condensed representation of a node and its subtree. Only present for SCALAR PlanNode(s).

Fields
description	string A string representation of the expression subtree rooted at this node.
subqueries	map<string, int32> A mapping of (subquery variable name) -> (subquery node id) for cases where the description string of this node references a SCALAR subquery contained in the expression subtree rooted at this node. The referenced SCALAR subquery may not necessarily be a direct child of this node.

QueryPlan

Contains an ordered list of nodes appearing in the query plan.

Fields
plan_nodes[]	PlanNode The nodes in the query plan. Plan nodes are returned in pre-order starting with the plan root. Each PlanNode's id corresponds to its index in plan_nodes.

ReadRequest

The request for Read and StreamingRead.

Fields
session	string Required. The session in which the read should be performed. Authorization requires the following IAM permission on the specified resource session: spanner.databases.read
transaction	TransactionSelector The transaction to use. If none is provided, the default is a temporary read-only transaction with strong concurrency.
table	string Required. The name of the table in the database to be read.
index	string If non-empty, the name of an index on table. This index is used instead of the table primary key when interpreting key_set and sorting result rows. See key_set for further information.
columns[]	string Required. The columns of table to be returned for each row matching this request.
key_set	KeySet Required. key_set identifies the rows to be yielded. key_set names the primary keys of the rows in table to be yielded, unless index is present. If index is present, then key_set instead names index keys in index. If the partition_token field is empty, rows are yielded in table primary key order (if index is empty) or index key order (if index is non-empty). If the partition_token field is not empty, rows will be yielded in an unspecified order. It is not an error for the key_set to name rows that do not exist in the database. Read yields nothing for nonexistent rows.
limit	int64 If greater than zero, only the first limit rows are yielded. If limit is zero, the default is no limit. A limit cannot be specified if partition_token is set.
resume_token	bytes If this request is resuming a previously interrupted read, resume_token should be copied from the last PartialResultSet yielded before the interruption. Doing this enables the new read to resume where the last read left off. The rest of the request parameters must exactly match the request that yielded this token.
partition_token	bytes If present, results will be restricted to the specified partition previously created using PartitionRead(). There must be an exact match for the values of fields common to this message and the PartitionReadRequest message used to create this partition_token.
request_options	RequestOptions Common options for this request.
directed_read_options	DirectedReadOptions Directed read options for this request.
data_boost_enabled	bool If this is for a partitioned read and this field is set to true, the request is executed with Spanner Data Boost independent compute resources. If the field is set to true but the request does not set partition_token, the API returns an INVALID_ARGUMENT error.

RequestOptions

Common request options for various APIs.

Fields
priority	Priority Priority for the request.
request_tag	string A per-request tag which can be applied to queries or reads, used for statistics collection. Both request_tag and transaction_tag can be specified for a read or query that belongs to a transaction. This field is ignored for requests where it's not applicable (e.g. CommitRequest). Legal characters for request_tag values are all printable characters (ASCII 32 - 126) and the length of a request_tag is limited to 50 characters. Values that exceed this limit are truncated. Any leading underscore (_) characters will be removed from the string.
transaction_tag	string A tag used for statistics collection about this transaction. Both request_tag and transaction_tag can be specified for a read or query that belongs to a transaction. The value of transaction_tag should be the same for all requests belonging to the same transaction. If this request doesn't belong to any transaction, transaction_tag will be ignored. Legal characters for transaction_tag values are all printable characters (ASCII 32 - 126) and the length of a transaction_tag is limited to 50 characters. Values that exceed this limit are truncated. Any leading underscore (_) characters will be removed from the string.

Priority

The relative priority for requests. Note that priority is not applicable for BeginTransaction.

The priority acts as a hint to the Cloud Spanner scheduler and does not guarantee priority or order of execution. For example:

• Some parts of a write operation always execute at PRIORITY_HIGH, regardless of the specified priority. This may cause you to see an increase in high priority workload even when executing a low priority request. This can also potentially cause a priority inversion where a lower priority request will be fulfilled ahead of a higher priority request.
• If a transaction contains multiple operations with different priorities, Cloud Spanner does not guarantee to process the higher priority operations first. There may be other constraints to satisfy, such as order of operations.

Enums
PRIORITY_UNSPECIFIED	PRIORITY_UNSPECIFIED is equivalent to PRIORITY_HIGH.
PRIORITY_LOW	This specifies that the request is low priority.
PRIORITY_MEDIUM	This specifies that the request is medium priority.
PRIORITY_HIGH	This specifies that the request is high priority.

ResultSet

Results from Read or ExecuteSql.

Fields
metadata	ResultSetMetadata Metadata about the result set, such as row type information.
rows[]	ListValue Each element in rows is a row whose format is defined by metadata.row_type. The ith element in each row matches the ith field in metadata.row_type. Elements are encoded based on type as described here.
stats	ResultSetStats Query plan and execution statistics for the SQL statement that produced this result set. These can be requested by setting ExecuteSqlRequest.query_mode. DML statements always produce stats containing the number of rows modified, unless executed using the ExecuteSqlRequest.QueryMode.PLAN ExecuteSqlRequest.query_mode. Other fields may or may not be populated, based on the ExecuteSqlRequest.query_mode.

ResultSetMetadata

Metadata about a ResultSet or PartialResultSet.

Fields
row_type	StructType Indicates the field names and types for the rows in the result set. For example, a SQL query like "SELECT UserId, UserName FROM Users" could return a row_type value like: "fields": [ { "name": "UserId", "type": { "code": "INT64" } }, { "name": "UserName", "type": { "code": "STRING" } }, ]
transaction	Transaction If the read or SQL query began a transaction as a side-effect, the information about the new transaction is yielded here.
undeclared_parameters	StructType A SQL query can be parameterized. In PLAN mode, these parameters can be undeclared. This indicates the field names and types for those undeclared parameters in the SQL query. For example, a SQL query like "SELECT * FROM Users where UserId = @userId and UserName = @userName " could return a undeclared_parameters value like: "fields": [ { "name": "UserId", "type": { "code": "INT64" } }, { "name": "UserName", "type": { "code": "STRING" } }, ]

ResultSetStats

Additional statistics about a ResultSet or PartialResultSet.

Fields
query_plan	QueryPlan QueryPlan for the query associated with this result.
query_stats	Struct Aggregated statistics from the execution of the query. Only present when the query is profiled. For example, a query could return the statistics as follows: { "rows_returned": "3", "elapsed_time": "1.22 secs", "cpu_time": "1.19 secs" }
Union field row_count. The number of rows modified by the DML statement. row_count can be only one of the following:
row_count_exact	int64 Standard DML returns an exact count of rows that were modified.
row_count_lower_bound	int64 Partitioned DML does not offer exactly-once semantics, so it returns a lower bound of the rows modified.

RollbackRequest

The request for Rollback.

Fields
session	string Required. The session in which the transaction to roll back is running. Authorization requires the following IAM permission on the specified resource session: spanner.databases.beginOrRollbackReadWriteTransaction
transaction_id	bytes Required. The transaction to roll back.

Session

A session in the Cloud Spanner API.

Fields
name	string Output only. The name of the session. This is always system-assigned.
labels	map<string, string> The labels for the session. Label keys must be between 1 and 63 characters long and must conform to the following regular expression: [a-z]([-a-z0-9]*[a-z0-9])?. Label values must be between 0 and 63 characters long and must conform to the regular expression ([a-z]([-a-z0-9]*[a-z0-9])?)?. No more than 64 labels can be associated with a given session. See https://goo.gl/xmQnxf for more information on and examples of labels.
create_time	Timestamp Output only. The timestamp when the session is created.
approximate_last_use_time	Timestamp Output only. The approximate timestamp when the session is last used. It is typically earlier than the actual last use time.
creator_role	string The database role which created this session.
multiplexed	bool Optional. If true, specifies a multiplexed session. Use a multiplexed session for multiple, concurrent read-only operations. Don't use them for read-write transactions, partitioned reads, or partitioned queries. Use CreateSession to create multiplexed sessions. Don't use BatchCreateSessions to create a multiplexed session. You can't delete or list multiplexed sessions.

StructType

StructType defines the fields of a STRUCT type.

Fields
fields[]	Field The list of fields that make up this struct. Order is significant, because values of this struct type are represented as lists, where the order of field values matches the order of fields in the StructType. In turn, the order of fields matches the order of columns in a read request, or the order of fields in the SELECT clause of a query.

Field

Message representing a single field of a struct.

Fields
name	string The name of the field. For reads, this is the column name. For SQL queries, it is the column alias (e.g., "Word" in the query "SELECT 'hello' AS Word"), or the column name (e.g., "ColName" in the query "SELECT ColName FROM Table"). Some columns might have an empty name (e.g., "SELECT UPPER(ColName)"). Note that a query result can contain multiple fields with the same name.
type	Type The type of the field.

Transaction

A transaction.

Fields
id	bytes id may be used to identify the transaction in subsequent Read, ExecuteSql, Commit, or Rollback calls. Single-use read-only transactions do not have IDs, because single-use transactions do not support multiple requests.
read_timestamp	Timestamp For snapshot read-only transactions, the read timestamp chosen for the transaction. Not returned by default: see TransactionOptions.ReadOnly.return_read_timestamp. A timestamp in RFC3339 UTC "Zulu" format, accurate to nanoseconds. Example: "2014-10-02T15:01:23.045123456Z".

TransactionOptions

Transactions:

Each session can have at most one active transaction at a time (note that standalone reads and queries use a transaction internally and do count towards the one transaction limit). After the active transaction is completed, the session can immediately be re-used for the next transaction. It is not necessary to create a new session for each transaction.

Transaction modes:

Cloud Spanner supports three transaction modes:

1. Locking read-write. This type of transaction is the only way to write data into Cloud Spanner. These transactions rely on pessimistic locking and, if necessary, two-phase commit. Locking read-write transactions may abort, requiring the application to retry.

2. Snapshot read-only. Snapshot read-only transactions provide guaranteed consistency across several reads, but do not allow writes. Snapshot read-only transactions can be configured to read at timestamps in the past, or configured to perform a strong read (where Spanner will select a timestamp such that the read is guaranteed to see the effects of all transactions that have committed before the start of the read). Snapshot read-only transactions do not need to be committed. Queries on change streams must be performed with the snapshot read-only transaction mode, specifying a strong read. See TransactionOptions.ReadOnly.strong for more details.

3. Partitioned DML. This type of transaction is used to execute a single Partitioned DML statement. Partitioned DML partitions the key space and runs the DML statement over each partition in parallel using separate, internal transactions that commit independently. Partitioned DML transactions do not need to be committed.

For transactions that only read, snapshot read-only transactions provide simpler semantics and are almost always faster. In particular, read-only transactions do not take locks, so they do not conflict with read-write transactions. As a consequence of not taking locks, they also do not abort, so retry loops are not needed.

Transactions may only read-write data in a single database. They may, however, read-write data in different tables within that database.

Locking read-write transactions:

Locking transactions may be used to atomically read-modify-write data anywhere in a database. This type of transaction is externally consistent.

Clients should attempt to minimize the amount of time a transaction is active. Faster transactions commit with higher probability and cause less contention. Cloud Spanner attempts to keep read locks active as long as the transaction continues to do reads, and the transaction has not been terminated by Commit or Rollback. Long periods of inactivity at the client may cause Cloud Spanner to release a transaction's locks and abort it.

Conceptually, a read-write transaction consists of zero or more reads or SQL statements followed by Commit. At any time before Commit, the client can send a Rollback request to abort the transaction.

Semantics:

Cloud Spanner can commit the transaction if all read locks it acquired are still valid at commit time, and it is able to acquire write locks for all writes. Cloud Spanner can abort the transaction for any reason. If a commit attempt returns ABORTED, Cloud Spanner guarantees that the transaction has not modified any user data in Cloud Spanner.

Unless the transaction commits, Cloud Spanner makes no guarantees about how long the transaction's locks were held for. It is an error to use Cloud Spanner locks for any sort of mutual exclusion other than between Cloud Spanner transactions themselves.

Retrying aborted transactions:

When a transaction aborts, the application can choose to retry the whole transaction again. To maximize the chances of successfully committing the retry, the client should execute the retry in the same session as the original attempt. The original session's lock priority increases with each consecutive abort, meaning that each attempt has a slightly better chance of success than the previous.

Note that the lock priority is preserved per session (not per transaction). Lock priority is set by the first read or write in the first attempt of a read-write transaction. If the application starts a new session to retry the whole transaction, the transaction loses its original lock priority. Moreover, the lock priority is only preserved if the transaction fails with an ABORTED error.

Under some circumstances (for example, many transactions attempting to modify the same row(s)), a transaction can abort many times in a short period before successfully committing. Thus, it is not a good idea to cap the number of retries a transaction can attempt; instead, it is better to limit the total amount of time spent retrying.

Idle transactions:

A transaction is considered idle if it has no outstanding reads or SQL queries and has not started a read or SQL query within the last 10 seconds. Idle transactions can be aborted by Cloud Spanner so that they don't hold on to locks indefinitely. If an idle transaction is aborted, the commit will fail with error ABORTED.

If this behavior is undesirable, periodically executing a simple SQL query in the transaction (for example, SELECT 1) prevents the transaction from becoming idle.

Snapshot read-only transactions:

Snapshot read-only transactions provides a simpler method than locking read-write transactions for doing several consistent reads. However, this type of transaction does not support writes.

Snapshot transactions do not take locks. Instead, they work by choosing a Cloud Spanner timestamp, then executing all reads at that timestamp. Since they do not acquire locks, they do not block concurrent read-write transactions.

Unlike locking read-write transactions, snapshot read-only transactions never abort. They can fail if the chosen read timestamp is garbage collected; however, the default garbage collection policy is generous enough that most applications do not need to worry about this in practice.

Snapshot read-only transactions do not need to call Commit or Rollback (and in fact are not permitted to do so).

To execute a snapshot transaction, the client specifies a timestamp bound, which tells Cloud Spanner how to choose a read timestamp.

The types of timestamp bound are:

• Strong (the default).
• Bounded staleness.
• Exact staleness.

If the Cloud Spanner database to be read is geographically distributed, stale read-only transactions can execute more quickly than strong or read-write transactions, because they are able to execute far from the leader replica.

Each type of timestamp bound is discussed in detail below.

Strong: Strong reads are guaranteed to see the effects of all transactions that have committed before the start of the read. Furthermore, all rows yielded by a single read are consistent with each other -- if any part of the read observes a transaction, all parts of the read see the transaction.

Strong reads are not repeatable: two consecutive strong read-only transactions might return inconsistent results if there are concurrent writes. If consistency across reads is required, the reads should be executed within a transaction or at an exact read timestamp.

Queries on change streams (see below for more details) must also specify the strong read timestamp bound.

See TransactionOptions.ReadOnly.strong.

Exact staleness:

These timestamp bounds execute reads at a user-specified timestamp. Reads at a timestamp are guaranteed to see a consistent prefix of the global transaction history: they observe modifications done by all transactions with a commit timestamp less than or equal to the read timestamp, and observe none of the modifications done by transactions with a larger commit timestamp. They will block until all conflicting transactions that may be assigned commit timestamps <= the read timestamp have finished.

The timestamp can either be expressed as an absolute Cloud Spanner commit timestamp or a staleness relative to the current time.

These modes do not require a "negotiation phase" to pick a timestamp. As a result, they execute slightly faster than the equivalent boundedly stale concurrency modes. On the other hand, boundedly stale reads usually return fresher results.

See TransactionOptions.ReadOnly.read_timestamp and TransactionOptions.ReadOnly.exact_staleness.

Bounded staleness:

Bounded staleness modes allow Cloud Spanner to pick the read timestamp, subject to a user-provided staleness bound. Cloud Spanner chooses the newest timestamp within the staleness bound that allows execution of the reads at the closest available replica without blocking.

All rows yielded are consistent with each other -- if any part of the read observes a transaction, all parts of the read see the transaction. Boundedly stale reads are not repeatable: two stale reads, even if they use the same staleness bound, can execute at different timestamps and thus return inconsistent results.

Boundedly stale reads execute in two phases: the first phase negotiates a timestamp among all replicas needed to serve the read. In the second phase, reads are executed at the negotiated timestamp.

As a result of the two phase execution, bounded staleness reads are usually a little slower than comparable exact staleness reads. However, they are typically able to return fresher results, and are more likely to execute at the closest replica.

Because the timestamp negotiation requires up-front knowledge of which rows will be read, it can only be used with single-use read-only transactions.

See TransactionOptions.ReadOnly.max_staleness and TransactionOptions.ReadOnly.min_read_timestamp.

Old read timestamps and garbage collection:

Cloud Spanner continuously garbage collects deleted and overwritten data in the background to reclaim storage space. This process is known as "version GC". By default, version GC reclaims versions after they are one hour old. Because of this, Cloud Spanner cannot perform reads at read timestamps more than one hour in the past. This restriction also applies to in-progress reads and/or SQL queries whose timestamp become too old while executing. Reads and SQL queries with too-old read timestamps fail with the error FAILED_PRECONDITION.

You can configure and extend the VERSION_RETENTION_PERIOD of a database up to a period as long as one week, which allows Cloud Spanner to perform reads up to one week in the past.

Querying change Streams:

A Change Stream is a schema object that can be configured to watch data changes on the entire database, a set of tables, or a set of columns in a database.

When a change stream is created, Spanner automatically defines a corresponding SQL Table-Valued Function (TVF) that can be used to query the change records in the associated change stream using the ExecuteStreamingSql API. The name of the TVF for a change stream is generated from the name of the change stream: READ_.

All queries on change stream TVFs must be executed using the ExecuteStreamingSql API with a single-use read-only transaction with a strong read-only timestamp_bound. The change stream TVF allows users to specify the start_timestamp and end_timestamp for the time range of interest. All change records within the retention period is accessible using the strong read-only timestamp_bound. All other TransactionOptions are invalid for change stream queries.

In addition, if TransactionOptions.read_only.return_read_timestamp is set to true, a special value of 2^63 - 2 will be returned in the Transaction message that describes the transaction, instead of a valid read timestamp. This special value should be discarded and not used for any subsequent queries.

Please see https://cloud.google.com/spanner/docs/change-streams for more details on how to query the change stream TVFs.

Partitioned DML transactions:

Partitioned DML transactions are used to execute DML statements with a different execution strategy that provides different, and often better, scalability properties for large, table-wide operations than DML in a ReadWrite transaction. Smaller scoped statements, such as an OLTP workload, should prefer using ReadWrite transactions.

Partitioned DML partitions the keyspace and runs the DML statement on each partition in separate, internal transactions. These transactions commit automatically when complete, and run independently from one another.

To reduce lock contention, this execution strategy only acquires read locks on rows that match the WHERE clause of the statement. Additionally, the smaller per-partition transactions hold locks for less time.

That said, Partitioned DML is not a drop-in replacement for standard DML used in ReadWrite transactions.

• The DML statement must be fully-partitionable. Specifically, the statement must be expressible as the union of many statements which each access only a single row of the table.

• The statement is not applied atomically to all rows of the table. Rather, the statement is applied atomically to partitions of the table, in independent transactions. Secondary index rows are updated atomically with the base table rows.

• Partitioned DML does not guarantee exactly-once execution semantics against a partition. The statement is applied at least once to each partition. It is strongly recommended that the DML statement should be idempotent to avoid unexpected results. For instance, it is potentially dangerous to run a statement such as UPDATE table SET column = column + 1 as it could be run multiple times against some rows.

• The partitions are committed automatically - there is no support for Commit or Rollback. If the call returns an error, or if the client issuing the ExecuteSql call dies, it is possible that some rows had the statement executed on them successfully. It is also possible that statement was never executed against other rows.

• Partitioned DML transactions may only contain the execution of a single DML statement via ExecuteSql or ExecuteStreamingSql.

• If any error is encountered during the execution of the partitioned DML operation (for instance, a UNIQUE INDEX violation, division by zero, or a value that cannot be stored due to schema constraints), then the operation is stopped at that point and an error is returned. It is possible that at this point, some partitions have been committed (or even committed multiple times), and other partitions have not been run at all.

Given the above, Partitioned DML is good fit for large, database-wide, operations that are idempotent, such as deleting old rows from a very large table.

Fields
Union field mode. Required. The type of transaction. mode can be only one of the following:
read_write	ReadWrite Transaction may write. Authorization to begin a read-write transaction requires spanner.databases.beginOrRollbackReadWriteTransaction permission on the session resource.
partitioned_dml	PartitionedDml Partitioned DML transaction. Authorization to begin a Partitioned DML transaction requires spanner.databases.beginPartitionedDmlTransaction permission on the session resource.
read_only	ReadOnly Transaction will not write. Authorization to begin a read-only transaction requires spanner.databases.beginReadOnlyTransaction permission on the session resource.

PartitionedDml

This type has no fields.

Message type to initiate a Partitioned DML transaction.

ReadOnly

Message type to initiate a read-only transaction.

Fields
return_read_timestamp	bool If true, the Cloud Spanner-selected read timestamp is included in the Transaction message that describes the transaction.
Union field timestamp_bound. How to choose the timestamp for the read-only transaction. timestamp_bound can be only one of the following:
strong	bool Read at a timestamp where all previously committed transactions are visible.
min_read_timestamp	Timestamp Executes all reads at a timestamp >= min_read_timestamp. This is useful for requesting fresher data than some previous read, or data that is fresh enough to observe the effects of some previously committed transaction whose timestamp is known. Note that this option can only be used in single-use transactions. A timestamp in RFC3339 UTC "Zulu" format, accurate to nanoseconds. Example: "2014-10-02T15:01:23.045123456Z".
max_staleness	Duration Read data at a timestamp >= NOW - max_staleness seconds. Guarantees that all writes that have committed more than the specified number of seconds ago are visible. Because Cloud Spanner chooses the exact timestamp, this mode works even if the client's local clock is substantially skewed from Cloud Spanner commit timestamps. Useful for reading the freshest data available at a nearby replica, while bounding the possible staleness if the local replica has fallen behind. Note that this option can only be used in single-use transactions.
read_timestamp	Timestamp Executes all reads at the given timestamp. Unlike other modes, reads at a specific timestamp are repeatable; the same read at the same timestamp always returns the same data. If the timestamp is in the future, the read will block until the specified timestamp, modulo the read's deadline. Useful for large scale consistent reads such as mapreduces, or for coordinating many reads against a consistent snapshot of the data. A timestamp in RFC3339 UTC "Zulu" format, accurate to nanoseconds. Example: "2014-10-02T15:01:23.045123456Z".
exact_staleness	Duration Executes all reads at a timestamp that is exact_staleness old. The timestamp is chosen soon after the read is started. Guarantees that all writes that have committed more than the specified number of seconds ago are visible. Because Cloud Spanner chooses the exact timestamp, this mode works even if the client's local clock is substantially skewed from Cloud Spanner commit timestamps. Useful for reading at nearby replicas without the distributed timestamp negotiation overhead of max_staleness.

ReadWrite

This type has no fields.

Message type to initiate a read-write transaction. Currently this transaction type has no options.

TransactionSelector

This message is used to select the transaction in which a Read or ExecuteSql call runs.

See TransactionOptions for more information about transactions.

Fields
Union field selector. If no fields are set, the default is a single use transaction with strong concurrency. selector can be only one of the following:
single_use	TransactionOptions Execute the read or SQL query in a temporary transaction. This is the most efficient way to execute a transaction that consists of a single SQL query.
id	bytes Execute the read or SQL query in a previously-started transaction.
begin	TransactionOptions Begin a new transaction and execute this read or SQL query in it. The transaction ID of the new transaction is returned in ResultSetMetadata.transaction, which is a Transaction.

Type

Type indicates the type of a Cloud Spanner value, as might be stored in a table cell or returned from an SQL query.

Fields
code	TypeCode Required. The TypeCode for this type.
array_element_type	Type If code == ARRAY, then array_element_type is the type of the array elements.
struct_type	StructType If code == STRUCT, then struct_type provides type information for the struct's fields.
type_annotation	TypeAnnotationCode The TypeAnnotationCode that disambiguates SQL type that Spanner will use to represent values of this type during query processing. This is necessary for some type codes because a single TypeCode can be mapped to different SQL types depending on the SQL dialect. type_annotation typically is not needed to process the content of a value (it doesn't affect serialization) and clients can ignore it on the read path.
proto_type_fqn	string If code == PROTO or code == ENUM, then proto_type_fqn is the fully qualified name of the proto type representing the proto/enum definition.

TypeAnnotationCode

TypeAnnotationCode is used as a part of Type to disambiguate SQL types that should be used for a given Cloud Spanner value. Disambiguation is needed because the same Cloud Spanner type can be mapped to different SQL types depending on SQL dialect. TypeAnnotationCode doesn't affect the way value is serialized.

Enums
TYPE_ANNOTATION_CODE_UNSPECIFIED	Not specified.
PG_NUMERIC	PostgreSQL compatible NUMERIC type. This annotation needs to be applied to Type instances having NUMERIC type code to specify that values of this type should be treated as PostgreSQL NUMERIC values. Currently this annotation is always needed for NUMERIC when a client interacts with PostgreSQL-enabled Spanner databases.
PG_JSONB	PostgreSQL compatible JSONB type. This annotation needs to be applied to Type instances having JSON type code to specify that values of this type should be treated as PostgreSQL JSONB values. Currently this annotation is always needed for JSON when a client interacts with PostgreSQL-enabled Spanner databases.

TypeCode

TypeCode is used as part of Type to indicate the type of a Cloud Spanner value.

Each legal value of a type can be encoded to or decoded from a JSON value, using the encodings described below. All Cloud Spanner values can be null, regardless of type; nulls are always encoded as a JSON null.

Enums
TYPE_CODE_UNSPECIFIED	Not specified.
BOOL	Encoded as JSON true or false.
INT64	Encoded as string, in decimal format.
FLOAT64	Encoded as number, or the strings "NaN", "Infinity", or "-Infinity".
FLOAT32	Encoded as number, or the strings "NaN", "Infinity", or "-Infinity".
TIMESTAMP	Encoded as string in RFC 3339 timestamp format. The time zone must be present, and must be "Z". If the schema has the column option allow_commit_timestamp=true, the placeholder string "spanner.commit_timestamp()" can be used to instruct the system to insert the commit timestamp associated with the transaction commit.
DATE	Encoded as string in RFC 3339 date format.
STRING	Encoded as string.
BYTES	Encoded as a base64-encoded string, as described in RFC 4648, section 4.
ARRAY	Encoded as list, where the list elements are represented according to array_element_type.
STRUCT	Encoded as list, where list element i is represented according to struct_type.fields[i].
NUMERIC	Encoded as string, in decimal format or scientific notation format. Decimal format: [+-]Digits[.[Digits]] or [+-][Digits].Digits Scientific notation: [+-]Digits[.[Digits]][ExponentIndicator[+-]Digits] or [+-][Digits].Digits[ExponentIndicator[+-]Digits] (ExponentIndicator is "e" or "E")
JSON	Encoded as a JSON-formatted string as described in RFC 7159. The following rules are applied when parsing JSON input: Whitespace characters are not preserved. If a JSON object has duplicate keys, only the first key is preserved. Members of a JSON object are not guaranteed to have their order preserved. JSON array elements will have their order preserved.
PROTO	Encoded as a base64-encoded string, as described in RFC 4648, section 4.
ENUM	Encoded as string, in decimal format.