public FdbRangeQuery <TId> LookupGreaterThan([NotNull] IFdbReadOnlyTransaction trans, TValue value, bool orEqual, bool reverse = false) { var prefix = this.Subspace.Keys.EncodePartial(value); if (!orEqual) { prefix = FdbKey.Increment(prefix); } var space = new KeySelectorPair( KeySelector.FirstGreaterThan(prefix), KeySelector.FirstGreaterOrEqual(this.Subspace.ToRange().End) ); return(trans .GetRange(space, new FdbRangeOptions { Reverse = reverse }) .Select((kvp) => this.Subspace.Keys.Decode(kvp.Key).Item2)); }
public async Task Test_Range_Except() { int K = 3; int N = 100; using (var db = await OpenTestPartitionAsync()) { // get a clean new directory var location = await GetCleanDirectory(db, "Queries", "Except"); // create K lists var lists = Enumerable.Range(0, K).Select(i => location.Partition.ByKey(i)).ToArray(); // lists[0] contains all multiples of 1 // lists[1] contains all multiples of 2 // lists[k-1] contains all multiples of K // more generally: lists[k][i] = (..., Intersect, k, i * (k + 1)) = (k, i) var series = Enumerable.Range(1, K).Select(k => Enumerable.Range(1, N).Select(x => k * x).ToArray()).ToArray(); //foreach(var serie in series) //{ // Console.WriteLine(String.Join(", ", serie)); //} for (int k = 0; k < K; k++) { //Console.WriteLine("> k = " + k); using (var tr = db.BeginTransaction(this.Cancellation)) { for (int i = 0; i < N; i++) { var key = lists[k].Keys.Encode(series[k][i]); var value = STuple.EncodeKey(k, i); //Console.WriteLine("> " + key + " = " + value); tr.Set(key, value); } await tr.CommitAsync(); } } // Intersect all lists together should produce all integers that are prime numbers IEnumerable <int> xs = series[0]; for (int i = 1; i < K; i++) { xs = xs.Except(series[i]); } var expected = xs.ToArray(); Log("Expected: {0}", String.Join(", ", expected)); using (var tr = db.BeginTransaction(this.Cancellation)) { var merge = tr.Except( lists.Select(list => KeySelectorPair.Create(list.Keys.ToRange())), kvp => location.Keys.DecodeLast <int>(kvp.Key) ); Assert.That(merge, Is.Not.Null); Assert.That(merge, Is.InstanceOf <FdbExceptIterator <KeyValuePair <Slice, Slice>, int, KeyValuePair <Slice, Slice> > >()); var results = await merge.ToListAsync(); Assert.That(results, Is.Not.Null); Assert.That(results.Count, Is.EqualTo(expected.Length)); for (int i = 0; i < results.Count; i++) { Assert.That(location.Keys.DecodeLast <int>(results[i].Key), Is.EqualTo(expected[i])); } } } }
/// <summary>Return a range of keys</summary> /// <param name="query">Source database query</param> /// <param name="range">Pair of key selectors</param> /// <returns>Query that will return the keys from the specified <paramref name="range"/></returns> public static IFdbAsyncSequenceQueryable <KeyValuePair <Slice, Slice> > Range(this IFdbDatabaseQueryable query, KeySelectorPair range) { if (query == null) { throw new ArgumentNullException(nameof(query)); } var expr = FdbQueryExpressions.Range(range); return(query.Provider.CreateSequenceQuery(expr)); }
public static FdbQueryRangeExpression RangeStartsWith(Slice prefix, FdbRangeOptions options = null) { // starts_with('A') means ['A', B') return(Range(KeySelectorPair.StartsWith(prefix), options)); }
public static FdbQueryRangeExpression Range(KeySelectorPair range, FdbRangeOptions options = null) { return(new FdbQueryRangeExpression(range, options)); }
internal FdbQueryRangeExpression(KeySelectorPair range, FdbRangeOptions options) { this.Range = range; this.Options = options; }
private static async Task BenchMergeSortAsync(IFdbDatabase db, int N, int K, int B, CancellationToken ct) { Console.WriteLine($"=== BenchMergeSort(N={N:N0}, K={K:N0}, B={B:N0}) ==="); // create multiple lists var location = db.Root.ByKey("MergeSort"); await db.WriteAsync(async tr => { var subspace = await location.Resolve(tr); tr.ClearRange(subspace); }, ct); var sources = Enumerable.Range(0, K).Select(i => 'A' + i).ToArray(); var rnd = new Random(); // insert a number of random number lists Console.Write($"> Inserting {(K * N):N0} items... "); foreach (var source in sources) { using (var tr = await db.BeginTransactionAsync(ct)) { var list = await location.ByKey(source).Resolve(tr); for (int i = 0; i < N; i++) { tr.Set(list.Encode(rnd.Next()), Slice.FromInt32(i)); } await tr.CommitAsync(); } } Console.WriteLine("Done"); // merge/sort them to get only one (hopefully sorted) list using (var tr = await db.BeginTransactionAsync(ct)) { var subspace = await location.Resolve(tr); var mergesort = tr .MergeSort( sources.Select(source => KeySelectorPair.StartsWith(subspace.Encode(source))), (kvp) => subspace.DecodeLast <int>(kvp.Key) ) .Take(B) .Select(kvp => subspace.Unpack(kvp.Key)); Console.Write($"> MergeSort with limit {B:N0}... "); var sw = Stopwatch.StartNew(); var results = await mergesort.ToListAsync(); sw.Stop(); Console.WriteLine("Done"); Console.WriteLine($"Took {FormatTimeMilli(sw.Elapsed.TotalMilliseconds)} to merge sort {results.Count:N0} results from {K} lists of {N} items each"); //foreach (var result in results) //{ // Console.WriteLine(result.Get<int>(-1)); //} } Console.WriteLine(); }