--- title: "POST /v1/{+session}:partitionRead" method: POST path: "/v1/{+session}:partitionRead" tags: ["projects"] --- # POST /v1/{+session}:partitionRead `POST /v1/{+session}: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 isn't possible to resume the read, and the whole operation must be restarted from the beginning. ## Path parameters - `session` string, required ## Request body - PartitionReadRequest — The request for PartitionRead - `transaction` TransactionSelector — This message is used to select the transaction in which a Read or ExecuteSql call runs. See TransactionOptions for more information about transactions. - `singleUse` TransactionOptions — Options to use for transactions. - `readWrite` ReadWrite — Message type to initiate a read-write transaction. Currently this transaction type has no options. - `readLockMode` 'READ_LOCK_MODE_UNSPECIFIED' | 'PESSIMISTIC' | 'OPTIMISTIC' — The read lock mode for the transaction. - `multiplexedSessionPreviousTransactionId` string, byte — Optional. Clients should pass the transaction ID of the previous transaction attempt that was aborted if this transaction is being executed on a multiplexed session. - `partitionedDml` PartitionedDml — Message type to initiate a Partitioned DML transaction. - `readOnly` ReadOnly — Message type to initiate a read-only transaction. - `strong` boolean — Read at a timestamp where all previously committed transactions are visible. - `minReadTimestamp` string, google-datetime — 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"`. - `maxStaleness` string, google-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. - `readTimestamp` string, google-datetime — 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 is blocked 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"`. - `exactStaleness` string, google-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`. - `returnReadTimestamp` boolean — If true, the Cloud Spanner-selected read timestamp is included in the Transaction message that describes the transaction. - `excludeTxnFromChangeStreams` boolean — When `exclude_txn_from_change_streams` is set to `true`, it prevents read or write transactions from being tracked in change streams. * If the DDL option `allow_txn_exclusion` is set to `true`, then the updates made within this transaction aren't recorded in the change stream. * If you don't set the DDL option `allow_txn_exclusion` or if it's set to `false`, then the updates made within this transaction are recorded in the change stream. When `exclude_txn_from_change_streams` is set to `false` or not set, modifications from this transaction are recorded in all change streams that are tracking columns modified by these transactions. The `exclude_txn_from_change_streams` option can only be specified for read-write or partitioned DML transactions, otherwise the API returns an `INVALID_ARGUMENT` error. - `isolationLevel` 'ISOLATION_LEVEL_UNSPECIFIED' | 'SERIALIZABLE' | 'REPEATABLE_READ' — Isolation level for the transaction. - `id` string, byte — Execute the read or SQL query in a previously-started transaction. - `begin` TransactionOptions — Options to use for transactions. - `readWrite` ReadWrite — Message type to initiate a read-write transaction. Currently this transaction type has no options. - `readLockMode` 'READ_LOCK_MODE_UNSPECIFIED' | 'PESSIMISTIC' | 'OPTIMISTIC' — The read lock mode for the transaction. - `multiplexedSessionPreviousTransactionId` string, byte — Optional. Clients should pass the transaction ID of the previous transaction attempt that was aborted if this transaction is being executed on a multiplexed session. - `partitionedDml` PartitionedDml — Message type to initiate a Partitioned DML transaction. - `readOnly` ReadOnly — Message type to initiate a read-only transaction. - `strong` boolean — Read at a timestamp where all previously committed transactions are visible. - `minReadTimestamp` string, google-datetime — 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"`. - `maxStaleness` string, google-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. - `readTimestamp` string, google-datetime — 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 is blocked 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"`. - `exactStaleness` string, google-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`. - `returnReadTimestamp` boolean — If true, the Cloud Spanner-selected read timestamp is included in the Transaction message that describes the transaction. - `excludeTxnFromChangeStreams` boolean — When `exclude_txn_from_change_streams` is set to `true`, it prevents read or write transactions from being tracked in change streams. * If the DDL option `allow_txn_exclusion` is set to `true`, then the updates made within this transaction aren't recorded in the change stream. * If you don't set the DDL option `allow_txn_exclusion` or if it's set to `false`, then the updates made within this transaction are recorded in the change stream. When `exclude_txn_from_change_streams` is set to `false` or not set, modifications from this transaction are recorded in all change streams that are tracking columns modified by these transactions. The `exclude_txn_from_change_streams` option can only be specified for read-write or partitioned DML transactions, otherwise the API returns an `INVALID_ARGUMENT` error. - `isolationLevel` 'ISOLATION_LEVEL_UNSPECIFIED' | 'SERIALIZABLE' | 'REPEATABLE_READ' — Isolation level for the transaction. - `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. - `keySet` 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. - `keys` array[] — 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. - unknown[] - unknown - `ranges` KeyRange[] — A list of key ranges. See KeyRange for more information about key range specifications. - `startClosed` unknown[] — If the start is closed, then the range includes all rows whose first `len(start_closed)` key columns exactly match `start_closed`. - unknown - `startOpen` unknown[] — If the start is open, then the range excludes rows whose first `len(start_open)` key columns exactly match `start_open`. - unknown - `endClosed` unknown[] — If the end is closed, then the range includes all rows whose first `len(end_closed)` key columns exactly match `end_closed`. - unknown - `endOpen` unknown[] — If the end is open, then the range excludes rows whose first `len(end_open)` key columns exactly match `end_open`. - unknown - `all` boolean — 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. - `partitionOptions` PartitionOptions — Options for a `PartitionQueryRequest` and `PartitionReadRequest`. - `partitionSizeBytes` string, 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 can be smaller or larger than this size request. - `maxPartitions` string, int64 — **Note:** This hint is currently ignored by `PartitionQuery` and `PartitionRead` requests. The desired maximum number of partitions to return. For example, this might 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 can be smaller or larger than this maximum count request. ## Response `200` Successful response --- [API](https://skmtc.net/google/apis/spanner.md) · [All operations](https://skmtc.net/google/apis/spanner/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/google/spanner/versions/4b66067d2622/schema)