Reference documentation and code samples for the Cloud Spanner Client class BatchSnapshot.
Represents a Read-Only Batch Transaction in Cloud Spanner.
Batch Snapshots can be shared with other servers or processes by casting the object to a string, or by calling Google\Cloud\Spanner\Batch\BatchSnapshot::serialize().
Please note that it is important that Snapshots are closed when they are no longer needed. Closing a snapshot is accomplished by calling Google\Cloud\Spanner\Batch\BatchSnapshot::close(). Snapshots should be closed only after all workers have finished processing. Closing a snapshot before all workers have processed will result in call failures.
Example:
use Google\Cloud\Spanner\SpannerClient;
$spanner = new SpannerClient();
$batch = $spanner->batch('instance-id', 'database-id');
$snapshot = $batch->snapshot();
// Serialize a snapshot to share it with another worker.
$snapshotString = (string) $snapshot;
// Calling BatchSnapshot::serialize() has the same effect.
$snapshotString = $snapshot->serialize();
Namespace
Google \ Cloud \ Spanner \ BatchMethods
__construct
Parameters | |
---|---|
Name | Description |
operation |
Google\Cloud\Spanner\Operation
The Operation instance. |
session |
Google\Cloud\Spanner\Session\Session
The session to use for spanner interactions. |
options |
array
Configuration Options. |
↳ id |
string
The Transaction ID. |
↳ readTimestamp |
Timestamp
The read timestamp. |
close
Closes all open resources.
When the snapshot is no longer needed, it is important to call this method to free up resources allocated by the Batch Client.
Methods on this instance which make service calls will fail if the snapshot has been closed.
Example:
$snapshot->close();
Parameter | |
---|---|
Name | Description |
options |
array
[optional] Configuration Options |
Returns | |
---|---|
Type | Description |
void |
partitionRead
Begin a partitioned read.
Example:
use Google\Cloud\Spanner\KeySet;
$keySet = new KeySet(['all' => true]);
$columns = ['id', 'firstName', 'lastName'];
$partitions = $snapshot->partitionRead('Users', $keySet, $columns);
Parameters | |
---|---|
Name | Description |
table |
string
The table name. |
keySet |
Google\Cloud\Spanner\KeySet
The KeySet to select rows. |
columns |
string[]
A list of column names to return. |
options |
array
Configuration Options |
↳ maxPartitions |
int
The desired maximum number of partitions to return. For example, this may be set to the number of workers available. The maximum value is currently 200,000. This is only a hint. The actual number of partitions returned may not always match the requested value. Defaults to |
↳ partitionSizeBytes |
int
The desired data size for each partition generated. This is only a hint. The actual size of each partition may be smaller or larger than this size request. Defaults to |
↳ index |
string
The name of an index on the table. |
↳ dataBoostEnabled |
bool
This is an optional parameter which can be used for partition read and query to execute the request via spanner independent compute resources. |
Returns | |
---|---|
Type | Description |
array<Google\Cloud\Spanner\Batch\ReadPartition> |
partitionQuery
Begin a partitioned SQL query.
Example:
use Google\Cloud\Spanner\Timestamp;
$queryString = 'SELECT * FROM Users WHERE joinDate < @joinDate AND lastLogin > @loginCutoff';
$partitions = $snapshot->partitionQuery($queryString, [
'parameters' => [
'joinDate' => new Timestamp(new \DateTime('2017-01-01')),
'loginDate' => new Timestamp(new \DateTime('2017-12-31'))
]
]);
Parameters | |
---|---|
Name | Description |
sql |
string
The query string to execute. |
options |
array
Configuration Options |
↳ maxPartitions |
int
The desired maximum number of partitions to return. For example, this may be set to the number of workers available. The maximum value is currently 200,000. This is only a hint. The actual number of partitions returned may not always match the requested value. Defaults to |
↳ partitionSizeBytes |
int
The desired data size for each partition generated. This is only a hint. The actual size of each partition may be smaller or larger than this size request. Defaults to |
↳ parameters |
array
A key/value array of Query Parameters, where the key is represented in the query string prefixed by a |
↳ types |
array
A key/value array of Query Parameter types. Generally, Google Cloud PHP can infer types. Explicit type definitions are only necessary for null parameter values. Accepted values are defined as constants on Google\Cloud\Spanner\ValueMapper, and are as follows: |
↳ dataBoostEnabled |
bool
This is an optional parameter which can be used for partition read and query to execute the request via spanner independent compute resources. |
Returns | |
---|---|
Type | Description |
array<Google\Cloud\Spanner\Batch\QueryPartition> |
executePartition
Read rows from a partition.
Partitions are created by calling Google\Cloud\Spanner\Batch\BatchSnapshot::partitionRead() or Google\Cloud\Spanner\Batch\BatchSnapshot::partitionQuery(). Generally, those partitions will be distributed to worker processes, each of which will call this method with the partition it was given.
Example:
$result = $snapshot->executePartition($partition);
Parameters | |
---|---|
Name | Description |
partition |
Google\Cloud\Spanner\Batch\PartitionInterface
The partition to read. |
options |
array
Configuration Options. |
Returns | |
---|---|
Type | Description |
Google\Cloud\Spanner\Result |
serialize
Return a stringified representation of the BatchSnapshot object.
Example:
$snapshotString = $snapshot->serialize();
Returns | |
---|---|
Type | Description |
string |
__toString
Cast the snapshot to a string.
Returns | |
---|---|
Type | Description |
string |