public sealed class Tablet : IMessage<Tablet>, IEquatable<Tablet>, IDeepCloneable<Tablet>, IBufferMessage, IMessageReference documentation and code samples for the Google Cloud Spanner v1 API class Tablet.
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.
Namespace
Google.Cloud.Spanner.V1Assembly
Google.Cloud.Spanner.V1.dll
Constructors
Tablet()
public Tablet()Tablet(Tablet)
public Tablet(Tablet other)| Parameter | |
|---|---|
| Name | Description |
other |
Tablet |
Properties
Distance
public uint Distance { get; set; }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.
| Property Value | |
|---|---|
| Type | Description |
uint |
|
Incarnation
public ByteString Incarnation { get; set; }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.
| Property Value | |
|---|---|
| Type | Description |
ByteString |
|
Location
public string Location { get; set; }Where this tablet is located. This is the name of a Google Cloud region, such as "us-central1".
| Property Value | |
|---|---|
| Type | Description |
string |
|
Role
public Tablet.Types.Role Role { get; set; }The role of the tablet.
| Property Value | |
|---|---|
| Type | Description |
TabletTypesRole |
|
ServerAddress
public string ServerAddress { get; set; }The address of the server that is serving this tablet -- either an IP address or DNS hostname and a port number.
| Property Value | |
|---|---|
| Type | Description |
string |
|
Skip
public bool Skip { get; set; }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.
| Property Value | |
|---|---|
| Type | Description |
bool |
|
TabletUid
public ulong TabletUid { get; set; }The UID of the tablet, unique within the database. Matches the
tablet_uids and leader_tablet_uid fields in Group.
| Property Value | |
|---|---|
| Type | Description |
ulong |
|