// Reads all Empty records from the specified file. Returns the number of records read.
static async Task <long> ReadAll(string fname)
{
using (var reader = new EmptyReader(fname)) {
long records = 0;
Stopwatch stopwatch = Stopwatch.StartNew();
await reader.ReadAfter(DateTime.MinValue).ForEachAsync((IEnumerable <Event <Empty> > buf) => {
records += buf.Count();
return(Task.CompletedTask);
});
double seconds = stopwatch.Elapsed.TotalSeconds;
long bytes = new FileInfo(fname).Length;
Console.WriteLine(" ReadAll: {0:N0} records, {1:N0} bytes, {2:N0} records/sec, {3:N0} bytes/sec.",
records, bytes, records / seconds, bytes / seconds);
return(records);
}
}
// Seeks to random timestamps in the file for the specified amount of time. The timestamps
// to seek are uniformly distributed in [0, maxTicks].
static async Task SeekMany(string fname, long maxTicks, double seconds)
{
if (maxTicks >= int.MaxValue)
{
throw new Exception("Sorry, not implemented");
}
var rng = new Random();
long seeks = 0;
Stopwatch stopwatch = Stopwatch.StartNew();
do
{
++seeks;
var t = new DateTime(rng.Next((int)maxTicks + 1), DateTimeKind.Utc);
// Create a new reader for every seek to avoid the possibility of caching in the reader.
using (var reader = new EmptyReader(fname)) {
// Note that this not only seeks but also reads and decompresses the content of the
// first chunk.
await reader.ReadAfter(t).GetAsyncEnumerator().MoveNextAsync(CancellationToken.None);
}
} while (stopwatch.Elapsed < TimeSpan.FromSeconds(seconds));
seconds = stopwatch.Elapsed.TotalSeconds;
Console.WriteLine(" SeekMany: {0:N0} seeks, {1:N1} seeks/sec.", seeks, seeks / seconds);
}