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.
Arguments
Parameters | |
---|---|
session |
Required. The session in which the read should be performed.
|
body |
Required.
|
Raised exceptions
Exceptions | |
---|---|
ConnectionError |
In case of a network problem (such as DNS failure or refused connection). |
HttpError |
If the response status is >= 400 (excluding 429 and 503). |
TimeoutError |
If a long-running operation takes longer to finish than the specified timeout limit. |
TypeError |
If an operation or function receives an argument of the wrong type. |
ValueError |
If an operation or function receives an argument of the right type but an inappropriate value. For example, a negative timeout. |
Response
If successful, the response contains an instance of ResultSet
.
Subworkflow snippet
Some fields might be optional or required. To identify required fields, refer to the API documentation.
YAML
- read: call: googleapis.spanner.v1.projects.instances.databases.sessions.read args: session: ... body: columns: ... index: ... keySet: all: ... keys: ... ranges: ... limit: ... partitionToken: ... requestOptions: priority: ... requestTag: ... transactionTag: ... resumeToken: ... table: ... transaction: begin: partitionedDml: ... readOnly: exactStaleness: ... maxStaleness: ... minReadTimestamp: ... readTimestamp: ... returnReadTimestamp: ... strong: ... readWrite: readLockMode: ... id: ... singleUse: ... result: readResult
JSON
[ { "read": { "call": "googleapis.spanner.v1.projects.instances.databases.sessions.read", "args": { "session": "...", "body": { "columns": "...", "index": "...", "keySet": { "all": "...", "keys": "...", "ranges": "..." }, "limit": "...", "partitionToken": "...", "requestOptions": { "priority": "...", "requestTag": "...", "transactionTag": "..." }, "resumeToken": "...", "table": "...", "transaction": { "begin": { "partitionedDml": "...", "readOnly": { "exactStaleness": "...", "maxStaleness": "...", "minReadTimestamp": "...", "readTimestamp": "...", "returnReadTimestamp": "...", "strong": "..." }, "readWrite": { "readLockMode": "..." } }, "id": "...", "singleUse": "..." } } }, "result": "readResult" } } ]