public async Task TestHybridTime()
{
// Perform one write so we receive a timestamp from the server and can use
// it to propagate a modified timestamp back to the server. Following writes
// should force the servers to update their clocks to this value and increment
// the logical component of the timestamp.
await InsertRowAsync("0");
Assert.NotEqual(KuduClient.NoTimestamp, _client.LastPropagatedTimestamp);
var(timestampMicros, logicalValue) = HybridTimeUtil.HtTimestampToPhysicalAndLogical(
_client.LastPropagatedTimestamp);
Assert.Equal(0, logicalValue);
long futureTs = timestampMicros + 5000000;
_client.LastPropagatedTimestamp = HybridTimeUtil.ClockTimestampToHtTimestamp(futureTs);
var logicalValues = new List <long>();
var keys = new[] { "1", "2", "3", "11", "22", "33" };
for (int i = 0; i < keys.Length; i++)
{
await InsertRowAsync(keys[i]);
Assert.NotEqual(KuduClient.NoTimestamp, _client.LastPropagatedTimestamp);
(timestampMicros, logicalValue) = HybridTimeUtil.HtTimestampToPhysicalAndLogical(
_client.LastPropagatedTimestamp);
Assert.Equal(futureTs, timestampMicros);
logicalValues.Add(logicalValue);
Assert.Equal(logicalValues.OrderBy(v => v), logicalValues);
}
// Scan all rows with READ_LATEST (the default), which should retrieve all rows.
var scanner = _client.NewScanBuilder(_table)
.SetReadMode(ReadMode.ReadLatest)
.Build();
Assert.Equal(1 + keys.Length, await scanner.CountAsync());
// Now scan at multiple snapshots with READ_AT_SNAPSHOT. The logical timestamp
// from the 'i'th row (counted from 0) combined with the latest physical timestamp
// should observe 'i + 1' rows.
for (int i = 0; i < logicalValues.Count; i++)
{
logicalValue = logicalValues[i];
long snapshotTime = HybridTimeUtil.PhysicalAndLogicalToHtTimestamp(
futureTs, logicalValue);
int expected = i + 1;
long numRows = await ScanAtSnapshotAsync(snapshotTime);
Assert.Equal(expected, numRows);
}
// The last snapshots needs to be one into the future w.r.t. the last write's
// timestamp to get all rows, but the snapshot timestamp can't be bigger than
// the propagated timestamp. Ergo increase the propagated timestamp first.
long latestLogicalValue = logicalValues[^ 1];
/// <summary>
/// Sets the timestamp the scan must be executed at, in microseconds since the Unix epoch.
/// None is used by default. Requires that the ReadMode is READ_AT_SNAPSHOT.
/// </summary>
/// <param name="timestamp">A long representing an instant in microseconds since the unix epoch.</param>
public TBuilder SnapshotTimestampMicros(long timestamp)
{
HtTimestamp = HybridTimeUtil.PhysicalAndLogicalToHtTimestamp(timestamp, 0);
return((TBuilder)this);
}
