Class Tablet (3.60.0)

Tablet(mapping=None, *, ignore_unknown_fields=False, **kwargs)

A Tablet represents a single replica of a Group. A tablet is served by a single server at a time, and can move between servers due to server death or simply load balancing.

Attributes

Name Description
tablet_uid int
The UID of the tablet, unique within the database. Matches the tablet_uids and leader_tablet_uid fields in Group.
server_address str
The address of the server that is serving this tablet -- either an IP address or DNS hostname and a port number.
location str
Where this tablet is located. In the Spanner managed service, this is the name of a region, such as "us-central1". In Spanner Omni, this is a previously created location.
role google.cloud.spanner_v1.types.Tablet.Role
The role of the tablet.
incarnation bytes
incarnation indicates the freshness of the tablet information contained in this proto. Incarnations can be compared lexicographically; if incarnation A is greater than incarnation B, then the Tablet corresponding to A is newer than the Tablet corresponding to B, and should be used preferentially.
distance int
Distances help the client pick the closest tablet out of the list of tablets for a given request. Tablets with lower distances should generally be preferred. Tablets with the same distance are approximately equally close; the client can choose arbitrarily. Distances do not correspond precisely to expected latency, geographical distance, or anything else. Distances should be compared only between tablets of the same group; they are not meaningful between different groups. A value of zero indicates that the tablet may be in the same zone as the client, and have minimum network latency. A value less than or equal to five indicates that the tablet is thought to be in the same region as the client, and may have a few milliseconds of network latency. Values greater than five are most likely in a different region, with non-trivial network latency. Clients should use the following algorithm: - If the request is using a directed read, eliminate any tablets that do not match the directed read's target zone and/or replica type. - (Read-write transactions only) Choose leader tablet if it has an distance <=5. -="" group="" and="" sort="" tablets="" by="" distance.="" choose="" a="" random="" tablet="" with="" the="" lowest="" distance.="" if="" the="" request="" is="" not="" a="" directed="" read,="" only="" consider="" replicas="" with="" distances=""><=5. -="" send="" the="" request="" to="" the="" fallback="" endpoint.="" the="" tablet="" picked="" by="" this="" algorithm="" may="" be="" skipped,="" either="" because="" it="" is="" marked="" as="">skip by the server or because the corresponding server is unreachable, flow controlled, etc. Skipped tablets should be added to the skipped_tablet_uid field in RoutingHint; the algorithm above should then be re-run without including the skipped tablet(s) to pick the next best tablet.
skip bool
If true, the tablet should not be chosen by the client. Typically, this signals that the tablet is unhealthy in some way. Tablets with skip set to true should be reported back to the server in RoutingHint.skipped_tablet_uid; this cues the server to send updated information for this tablet should it become usable again.

Classes

Role

Role(value)

Indicates the role of the tablet.