Common request options for various APIs.
Priority for the request.
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.
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.
Inheritancebuiltins.object > proto.message.Message > RequestOptions
The relative priority for requests. Note that priority is not
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.