public sealed class TimestampBound : IEquatable<TimestampBound>Reference documentation and code samples for the Google.Cloud.Spanner.Data class TimestampBound.
Indicates how Spanner will choose a timestamp at which to read the data for read-only transactions.
Implements
IEquatableTimestampBoundNamespace
Google.Cloud.Spanner.DataAssembly
Google.Cloud.Spanner.Data.dll
Properties
Mode
public TimestampBoundMode Mode { get; }Indicates how to choose the timestamp at which to read the data for Cloud Spanner read-only transactions. If your application can tolerate some staleness when reading data, you can use a stale read, which can execute much faster when compared to reading the latest data. The types of timestamp bounds are: Strong (the default): read the latest data. Bounded staleness: read a version of the data that's no staler than a bound. Exact staleness: read the version of the data at an exact timestamp.
| Property Value | |
|---|---|
| Type | Description |
TimestampBoundMode |
|
ReturnReadTimestamp
public bool ReturnReadTimestamp { get; }If true, the read timestamp is included in the Google.Cloud.Spanner.V1.Transaction message that describes the transaction.
| Property Value | |
|---|---|
| Type | Description |
bool |
|
Staleness
public TimeSpan Staleness { get; }If Mode is ExactStaleness or MaxStaleness, this indicates the duration of time for the staleness.
| Property Value | |
|---|---|
| Type | Description |
TimeSpan |
|
Strong
public static TimestampBound Strong { get; }Read at a timestamp where all previously committed transactions are visible.
| Property Value | |
|---|---|
| Type | Description |
TimestampBound |
|
Timestamp
public DateTime Timestamp { get; }If Mode is ReadTimestamp or MinReadTimestamp, this indicates the timestamp to use.
| Property Value | |
|---|---|
| Type | Description |
DateTime |
|
Methods
FromBase64String(string)
public static TimestampBound FromBase64String(string base64String)Creates an instance of TimestampBound given its Base64 encoded string.
| Parameter | |
|---|---|
| Name | Description |
base64String |
stringThe string provided by ToBase64String(). |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A new instance of TimestampBound. |
GetHashCode()
public override int GetHashCode()Serves as the default hash function.
| Returns | |
|---|---|
| Type | Description |
int |
A hash code for the current object. |
OfExactStaleness(TimeSpan)
public static TimestampBound OfExactStaleness(TimeSpan duration)Executes all reads at a timestamp that is duration
old. The timestamp is chosen soon after the read is started.
Guarantees that all writes that have committed more than the specified number of seconds ago are visible. Because Cloud Spanner chooses the exact timestamp, this mode works even if the client's local clock is substantially skewed from Cloud Spanner commit timestamps.
Useful for reading at nearby replicas without the distributed timestamp negotiation overhead of OfMaxStaleness(TimeSpan).
| Parameter | |
|---|---|
| Name | Description |
duration |
TimeSpanThe exact staleness to use. Must not be negative. |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A created TimestampBound. |
OfMaxStaleness(TimeSpan)
public static TimestampBound OfMaxStaleness(TimeSpan duration)Read data at a timestamp >= NOW - <code class="paramref">duration</code>. Guarantees that all
writes that have committed more than the specified number of seconds ago are
visible.
Because Cloud Spanner chooses the exact timestamp, this mode works even if
the client's local clock is substantially skewed from Cloud Spanner
commit timestamps.
Useful for reading the freshest data available at a nearby replica, while bounding the possible staleness if the local replica has fallen behind.
Note that this option can only be used in single-use transactions.
| Parameter | |
|---|---|
| Name | Description |
duration |
TimeSpanThe maximum duration of staleness to use. Must not be negative. |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A created TimestampBound. |
OfMinReadTimestamp(DateTime)
public static TimestampBound OfMinReadTimestamp(DateTime minReadTimestamp)Executes all reads at a timestamp >= minReadTimestamp.
This is useful for requesting fresher data than some previous read, or data that is fresh enough to observe the effects of some previously committed transaction whose timestamp is known.
Note that this option can only be used in single-use transactions
| Parameter | |
|---|---|
| Name | Description |
minReadTimestamp |
DateTimeThe earliest timestamp to read from. Must be in UTC. |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A created TimestampBound. |
OfReadTimestamp(DateTime)
public static TimestampBound OfReadTimestamp(DateTime timestamp)Executes all reads at the given timestamp. Unlike other modes, reads at a specific timestamp are repeatable; the same read at the same timestamp always returns the same data. If the timestamp is in the future, the read will block until the specified timestamp, modulo the read's deadline.
Useful for large scale consistent reads such as mapreduces, or for coordinating many reads against a consistent snapshot of the data.
| Parameter | |
|---|---|
| Name | Description |
timestamp |
DateTimeThe timestamp to read from. Must be in UTC. |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A created TimestampBound. |
ToBase64String()
public string ToBase64String()Returns a Base64 encoded string that can later be serialized back into a TimestampBound using FromBase64String(string)
| Returns | |
|---|---|
| Type | Description |
string |
The base64 encoded string. |
WithReturnReadTimestamp(bool)
public TimestampBound WithReturnReadTimestamp(bool returnReadTimestamp)Creates a TimestampBound with the given value on whether to return a read timestamp.
| Parameter | |
|---|---|
| Name | Description |
returnReadTimestamp |
boolWhether to return a read timestamp. |
| Returns | |
|---|---|
| Type | Description |
TimestampBound |
A created TimestampBound. |