private async Task <Slice> GetPreviousNodeAsync(IFdbTransaction trans, int level, Slice key)
{
// GetPreviousNodeAsync looks for the previous node on a level, but "doesn't care"
// about the contents of that node. It therefore uses a non-isolated (snaphot)
// read and explicitly adds a conflict range that is exclusive of the actual,
// found previous node. This allows an increment of that node not to trigger
// a transaction conflict. We also add a conflict key on the found previous
// key in level 0. This allows detection of erasures.
var k = this.Subspace.Encode(level, key);
//Console.WriteLine(k);
//Console.WriteLine("GetPreviousNode(" + level + ", " + key + ")");
//Console.WriteLine(KeySelector.LastLessThan(k) + " <= x < " + KeySelector.FirstGreaterOrEqual(k));
var kv = await trans
.Snapshot
.GetRange(
KeySelector.LastLessThan(k),
KeySelector.FirstGreaterOrEqual(k)
)
.FirstAsync()
.ConfigureAwait(false);
//Console.WriteLine("Found " + FdbKey.Dump(kv.Key));
var prevKey = this.Subspace.DecodeLast <Slice>(kv.Key);
trans.AddReadConflictRange(kv.Key + FdbKey.MinValue, k);
trans.AddReadConflictKey(this.Subspace.Encode(0, prevKey));
return(prevKey);
}
private async Task <long> GetNextIndexAsync([NotNull] IFdbReadOnlyTransaction tr, IFdbDynamicSubspace subspace)
{
var range = subspace.Keys.ToRange();
var lastKey = await tr.GetKeyAsync(KeySelector.LastLessThan(range.End)).ConfigureAwait(false);
if (lastKey < range.Begin)
{
return(0);
}
return(subspace.Keys.DecodeFirst <long>(lastKey) + 1);
}
private async Task PushQueueAsync(IFdbTransaction tr, IDynamicKeySubspace queue, Slice taskId)
{
//TODO: use a high contention algo ?
// - must support Push and Pop
// - an empty queue must correspond to an empty subspace
// get the current size of the queue
var range = queue.Keys.ToRange();
var lastKey = await tr.Snapshot.GetKeyAsync(KeySelector.LastLessThan(range.End)).ConfigureAwait(false);
int count = lastKey < range.Begin ? 0 : queue.Keys.DecodeFirst <int>(lastKey) + 1;
// set the value
tr.Set(queue.Keys.Encode(count, GetRandomId()), taskId);
}
public async void Test_Case_11()
{
using (var zedb = await OpenTestDatabaseAsync())
{
var db = FoundationDB.Filters.Logging.FdbLoggingExtensions.Logged(zedb, (tr) => Log(tr.Log.GetTimingsReport(true)));
{
var subspace = db.GlobalSpace;
// clear everything and write some values
await db.WriteAsync((tr) =>
{
tr.ClearRange(subspace.Keys.Encode("K0000"), subspace.Keys.Encode("K9999Z"));
for (int i = 0; i < 100; i++)
{
tr.Set(subspace.Keys.Encode("K" + i.ToString("D4")), Slice.FromString("V" + i.ToString("D4")));
}
}, this.Cancellation);
using (var tr = db.BeginTransaction(this.Cancellation))
{
tr.ClearRange(subspace.Keys.Encode("K0010"), subspace.Keys.Encode("K0020"));
tr.ClearRange(subspace.Keys.Encode("K0050"), subspace.Keys.Encode("K0060"));
tr.Set(subspace.Keys.Encode("K0021"), Slice.Empty);
tr.Set(subspace.Keys.Encode("K0042"), Slice.Empty);
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0005")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0010")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0015")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0022")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0049")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0050")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0055")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0061")));
//no commit
}
using (var tr = db.BeginTransaction(this.Cancellation))
{
//tr.SetOption(FdbTransactionOption.ReadYourWritesDisable);
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0000"))); // equal=false, offset=1
await tr.GetKeyAsync(KeySelector.FirstGreaterThan(subspace.Keys.Encode("K0011"))); // equal=true, offset=1
await tr.GetKeyAsync(KeySelector.LastLessOrEqual(subspace.Keys.Encode("K0022"))); // equal=true, offset=0
await tr.GetKeyAsync(KeySelector.LastLessThan(subspace.Keys.Encode("K0033"))); // equal=false, offset=0
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Keys.Encode("K0040")) + 1000); // equal=false, offset=7 ?
await tr.GetKeyAsync(KeySelector.LastLessThan(subspace.Keys.Encode("K0050")) + 1000); // equal=false, offset=6 ?
}
}
}
}
public async Task Test_Case_11()
{
using (var db = await OpenTestPartitionAsync())
{
db.SetDefaultLogHandler((log) => Log(log.GetTimingsReport(true)));
var location = db.Root;
// clear everything and write some values
await db.WriteAsync(async tr =>
{
var subspace = await location.Resolve(tr);
tr.ClearRange(subspace.Encode("K0000"), subspace.Encode("K9999Z"));
for (int i = 0; i < 100; i++)
{
tr.Set(subspace.Encode("K" + i.ToString("D4")), Value("V" + i.ToString("D4")));
}
}, this.Cancellation);
using (var tr = await db.BeginTransactionAsync(this.Cancellation))
{
var subspace = await location.Resolve(tr);
tr.ClearRange(subspace.Encode("K0010"), subspace.Encode("K0020"));
tr.ClearRange(subspace.Encode("K0050"), subspace.Encode("K0060"));
tr.Set(subspace.Encode("K0021"), Slice.Empty);
tr.Set(subspace.Encode("K0042"), Slice.Empty);
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0005")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0010")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0015")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0022")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0049")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0050")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0055")));
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0061")));
//no commit
}
using (var tr = await db.BeginTransactionAsync(this.Cancellation))
{
var subspace = await location.Resolve(tr);
//tr.SetOption(FdbTransactionOption.ReadYourWritesDisable);
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0000"))); // equal=false, offset=1
await tr.GetKeyAsync(KeySelector.FirstGreaterThan(subspace.Encode("K0011"))); // equal=true, offset=1
await tr.GetKeyAsync(KeySelector.LastLessOrEqual(subspace.Encode("K0022"))); // equal=true, offset=0
await tr.GetKeyAsync(KeySelector.LastLessThan(subspace.Encode("K0033"))); // equal=false, offset=0
await tr.GetKeyAsync(KeySelector.FirstGreaterOrEqual(subspace.Encode("K0040")) + 1000); // equal=false, offset=7 ?
await tr.GetKeyAsync(KeySelector.LastLessThan(subspace.Encode("K0050")) + 1000); // equal=false, offset=6 ?
}
}
}