Class Priority (3.40.1)


The relative priority for requests. Note that priority is not applicable for BeginTransaction][google.spanner.v1.Spanner.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.

Values: PRIORITY_UNSPECIFIED (0): PRIORITY_UNSPECIFIED is equivalent to PRIORITY_HIGH. PRIORITY_LOW (1): This specifies that the request is low priority. PRIORITY_MEDIUM (2): This specifies that the request is medium priority. PRIORITY_HIGH (3): This specifies that the request is high priority.