RequestOptions

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Common request options for various APIs.

JSON representation
{
  "priority": enum (Priority),
  "requestTag": string,
  "transactionTag": string
}
Fields
priority

enum (Priority)

Priority for the request.

requestTag

string

A per-request tag which can be applied to queries or reads, used for statistics collection. Both requestTag and transactionTag 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 requestTag values are all printable characters (ASCII 32 - 126) and the length of a requestTag is limited to 50 characters. Values that exceed this limit are truncated. Any leading underscore (_) characters will be removed from the string.

transactionTag

string

A tag used for statistics collection about this transaction. Both requestTag and transactionTag can be specified for a read or query that belongs to a transaction. The value of transactionTag should be the same for all requests belonging to the same transaction. If this request doesn't belong to any transaction, transactionTag will be ignored. Legal characters for transactionTag values are all printable characters (ASCII 32 - 126) and the length of a transactionTag 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 sessions.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.