perf: batch repository reads, index snapshots, centralize date encoding

- Add IEventRepository/IResultRepository.GetManyAsync to kill N+1 lookups at
  6 sites (backtest, outcome eval, both bet-journal paths, anomaly browsing,
  results selection); guarded by a Received(1).GetManyAsync test.
- Add EventRepository.QueryAsync to push date+sport filtering to SQL (was
  load-whole-range-then-filter); search/sort stay in-memory for Cyrillic order.
- Add AnomalyRepository.CountSinceAsync (unread badge) + ListByDateRangeAsync
  (feed date filter); add Event/Snapshot count methods for the dashboard.
- Add composite indexes IX_Snapshots_EventCode_CapturedAt and
  _EventCode_Source_CapturedAt via a new migration + model snapshot.
- Introduce SqliteDateText as the single source of the O-format date encoding
  shared by Mapping (read/write) and the repositories' range predicates.
- Fix LiveOddsPoller cadence drift (budget sleep against cycle time); make
  DetectAnomalies dedup O(1) per event; add Event.Title to dedup the title join.

Tests adapted to the batched GetManyAsync via a TestFixtures bridge.

src/Marathon.Application/Abstractions/IAnomalyRepository.cs

@@ -5,4 +5,22 @@ namespace Marathon.Application.Abstractions;
 /// <summary>
 /// Repository for <see cref="Anomaly"/> domain entities.
 /// </summary>
-public interface IAnomalyRepository : IRepository<Guid, Anomaly>;
+public interface IAnomalyRepository : IRepository<Guid, Anomaly>
+{
+    /// <summary>
+    /// Server-side count of anomalies detected strictly after <paramref name="since"/>.
+    /// Backs the unread badge without materialising the table.
+    /// </summary>
+    Task<int> CountSinceAsync(DateTimeOffset since, CancellationToken ct = default);
+
+    /// <summary>
+    /// Anomalies whose <see cref="Anomaly.DetectedAt"/> falls in the inclusive
+    /// [<paramref name="from"/>..<paramref name="to"/>] window (either bound may be
+    /// null for open-ended), ordered newest-first. Pushes the temporal filter to SQL;
+    /// severity / sport filtering remains a service concern (needs the event join).
+    /// </summary>
+    Task<IReadOnlyList<Anomaly>> ListByDateRangeAsync(
+        DateTimeOffset? from,
+        DateTimeOffset? to,
+        CancellationToken ct = default);
+}

src/Marathon.Application/Abstractions/IEventRepository.cs

@@ -11,8 +11,27 @@ public interface IEventRepository : IRepository<EventId, Event>
 {
     Task<IReadOnlyList<Event>> ListByDateRangeAsync(DateRange range, CancellationToken ct = default);
 
+    /// <summary>
+    /// Date-range + sport-filtered query pushed to the database. Replaces the
+    /// "load the whole date range then filter sports in memory" path on the list
+    /// pages. Locale-sensitive search and sort remain a service-layer concern.
+    /// </summary>
+    Task<IReadOnlyList<Event>> QueryAsync(EventQuery query, CancellationToken ct = default);
+
+    /// <summary>
+    /// Batched point-lookup: loads many events in a single query, keyed by
+    /// <see cref="EventId"/>. Missing ids are simply absent from the dictionary.
+    /// Replaces per-id <see cref="IRepository{TKey,TEntity}.GetAsync"/> loops (N+1).
+    /// </summary>
+    Task<IReadOnlyDictionary<EventId, Event>> GetManyAsync(
+        IReadOnlyCollection<EventId> ids,
+        CancellationToken ct = default);
+
     Task<IReadOnlyList<Event>> ListBySportAsync(SportCode sport, CancellationToken ct = default);
 
+    /// <summary>Server-side total event count (dashboard summary).</summary>
+    Task<int> CountAsync(CancellationToken ct = default);
+
     /// <summary>
     /// Distinct sport codes across the events table. Projects in the database
     /// rather than materialising every <see cref="Event"/> on the client.

src/Marathon.Application/Abstractions/IResultRepository.cs

@@ -6,4 +6,14 @@ namespace Marathon.Application.Abstractions;
 /// <summary>
 /// Repository for <see cref="EventResult"/> domain entities.
 /// </summary>
-public interface IResultRepository : IRepository<EventId, EventResult>;
+public interface IResultRepository : IRepository<EventId, EventResult>
+{
+    /// <summary>
+    /// Batched point-lookup: loads many results in a single query, keyed by
+    /// <see cref="EventId"/>. Missing ids are simply absent from the dictionary.
+    /// Replaces per-id <see cref="IRepository{TKey,TEntity}.GetAsync"/> loops (N+1).
+    /// </summary>
+    Task<IReadOnlyDictionary<EventId, EventResult>> GetManyAsync(
+        IReadOnlyCollection<EventId> ids,
+        CancellationToken ct = default);
+}

src/Marathon.Application/Abstractions/ISnapshotRepository.cs

@@ -16,6 +16,12 @@ public interface ISnapshotRepository
 {
     Task<IReadOnlyList<OddsSnapshot>> ListAsync(CancellationToken ct = default);
 
+    /// <summary>
+    /// Server-side count of snapshots captured at or after <paramref name="since"/>.
+    /// Backs the dashboard "snapshots today" stat without materialising rows.
+    /// </summary>
+    Task<int> CountSinceAsync(DateTimeOffset since, CancellationToken ct = default);
+
     Task<IReadOnlyList<OddsSnapshot>> ListByEventAsync(
         EventId eventId,
         DateTimeOffset from,

src/Marathon.Application/Storage/EventQuery.cs

@@ -0,0 +1,13 @@
+namespace Marathon.Application.Storage;
+
+/// <summary>
+/// Database-pushdown query for the event list pages: an inclusive date range plus
+/// an optional sport-code filter. Locale-sensitive search and sort are deliberately
+/// NOT part of this contract — they stay in the service layer where Cyrillic
+/// ordinal semantics are preserved (SQLite BINARY collation would change them).
+/// </summary>
+/// <param name="Dates">Inclusive scheduled-at window.</param>
+/// <param name="SportCodes">When non-empty, restricts to these sport codes. Null/empty = all sports.</param>
+public sealed record EventQuery(
+    DateRange Dates,
+    IReadOnlyCollection<int>? SportCodes = null);

src/Marathon.Application/UseCases/BuildBetJournalReportUseCase.cs

@@ -54,16 +54,17 @@ public sealed class BuildBetJournalReportUseCase
 
         var distinctEventIds = bets.Select(b => b.EventId).Distinct().ToList();
 
-        // Resolve closing snapshot per event using a single-row repo call —
+        // Batch the event loads (was N+1). The closing-snapshot lookup stays per-event
-        // pushes the ORDER BY / LIMIT 1 down to SQLite rather than materialising
+        // because it pushes ORDER BY / LIMIT 1 down to SQLite (one indexed row each)
-        // every snapshot in a 30-day window.
+        // and is parameterised by that event's ScheduledAt.
+        var events = await _events.GetManyAsync(distinctEventIds, ct).ConfigureAwait(false);
+
         var closingByEvent = new Dictionary<DomainEventId, OddsSnapshot?>(distinctEventIds.Count);
         foreach (var eventId in distinctEventIds)
         {
             ct.ThrowIfCancellationRequested();
 
-            var ev = await _events.GetAsync(eventId, ct).ConfigureAwait(false);
+            if (!events.TryGetValue(eventId, out var ev))
-            if (ev is null)
             {
                 closingByEvent[eventId] = null;
                 continue;

src/Marathon.Application/UseCases/DetectAnomaliesUseCase.cs

@@ -30,10 +30,10 @@ public sealed class DetectAnomaliesUseCase
     // Dedup window: two anomalies for the same event within this window are considered duplicates.
     private static readonly TimeSpan DedupWindow = TimeSpan.FromMinutes(1);
 
-    private readonly IEventRepository    _eventRepo;
+    private readonly IEventRepository _eventRepo;
     private readonly ISnapshotRepository _snapshotRepo;
-    private readonly IAnomalyRepository  _anomalyRepo;
+    private readonly IAnomalyRepository _anomalyRepo;
-    private readonly AnomalyOptions      _options;
+    private readonly AnomalyOptions _options;
     private readonly ILogger<DetectAnomaliesUseCase> _logger;
 
     public DetectAnomaliesUseCase(
@@ -43,11 +43,11 @@ public sealed class DetectAnomaliesUseCase
         IOptions<AnomalyOptions> options,
         ILogger<DetectAnomaliesUseCase> logger)
     {
-        _eventRepo    = eventRepo    ?? throw new ArgumentNullException(nameof(eventRepo));
+        _eventRepo = eventRepo ?? throw new ArgumentNullException(nameof(eventRepo));
         _snapshotRepo = snapshotRepo ?? throw new ArgumentNullException(nameof(snapshotRepo));
-        _anomalyRepo  = anomalyRepo  ?? throw new ArgumentNullException(nameof(anomalyRepo));
+        _anomalyRepo = anomalyRepo ?? throw new ArgumentNullException(nameof(anomalyRepo));
-        _options      = (options     ?? throw new ArgumentNullException(nameof(options))).Value;
+        _options = (options ?? throw new ArgumentNullException(nameof(options))).Value;
-        _logger       = logger       ?? throw new ArgumentNullException(nameof(logger));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
     }
 
     /// <summary>
@@ -67,13 +67,16 @@ public sealed class DetectAnomaliesUseCase
         var events = await _eventRepo.ListAsync(ct);
         int newAnomalyCount = 0;
 
-        var now  = MoscowTime.Now;
+        var now = MoscowTime.Now;
         var from = now - SnapshotLookback;
 
         // Hoisted outside the per-event loop: load existing anomalies ONCE per cycle
-        // and slice per-event in the loop. Previously this was reloaded per event
+        // and index them by event so dedup is O(1) per event instead of scanning the
-        // (O(N_events) round-trips). Reviewer W1, Phase 7.
+        // whole list each time (was O(events × anomalies)). Reviewer W1, Phase 7.
         var existingAnomalies = await _anomalyRepo.ListAsync(ct);
+        var existingByEvent = existingAnomalies
+            .GroupBy(a => a.EventId)
+            .ToDictionary(g => g.Key, g => g.ToList());
 
         // Single batched query for all events' snapshots — replaces the prior
         // per-event ListByEventAsync round-trip (O(N) SQLite hits + N Include(Bets)
@@ -90,7 +93,10 @@ public sealed class DetectAnomaliesUseCase
                 var snapshots = snapshotsByEvent.TryGetValue(ev.Id, out var found)
                     ? found
                     : Array.Empty<OddsSnapshot>();
-                newAnomalyCount += await ProcessEventAsync(detector, ev, snapshots, existingAnomalies, ct);
+                var existingForEvent = existingByEvent.TryGetValue(ev.Id, out var slice)
+                    ? slice
+                    : new List<Anomaly>();
+                newAnomalyCount += await ProcessEventAsync(detector, ev, snapshots, existingForEvent, ct);
             }
             catch (OperationCanceledException)
             {
@@ -117,7 +123,7 @@ public sealed class DetectAnomaliesUseCase
         AnomalyDetector detector,
         Event ev,
         IReadOnlyList<OddsSnapshot> snapshots,
-        IReadOnlyList<Anomaly> existingAnomalies,
+        List<Anomaly> existingForEvent,
         CancellationToken ct)
     {
         var detected = detector.Detect(ev.Id, snapshots);
@@ -125,11 +131,6 @@ public sealed class DetectAnomaliesUseCase
         if (detected.Count == 0)
             return 0;
 
-        // Slice the cycle-wide existing-anomaly list to just this event for dedup.
-        var existingForEvent = existingAnomalies
-            .Where(a => a.EventId == ev.Id)
-            .ToList();
-
         int persisted = 0;
         foreach (var anomaly in detected)
         {
@@ -151,7 +152,7 @@ public sealed class DetectAnomaliesUseCase
         // and their DetectedAt timestamps fall within the dedup window.
         return existing.Any(a =>
             a.EventId == candidate.EventId &&
-            a.Kind    == candidate.Kind    &&
+            a.Kind == candidate.Kind &&
             Math.Abs((a.DetectedAt - candidate.DetectedAt).TotalMinutes) <=
                 DedupWindow.TotalMinutes);
     }

src/Marathon.Application/UseCases/EvaluateAnomalyOutcomesUseCase.cs

@@ -75,29 +75,16 @@ public sealed class EvaluateAnomalyOutcomesUseCase
             return EmptyReport();
         }
 
-        // Build event + result lookups — distinct keys only to avoid quadratic loads.
+        // Batched lookups — a single query each, replacing the prior per-event
-        // TODO (perf, future): batch via IEventRepository.GetManyAsync / IResultRepository.GetManyAsync
+        // GetAsync round-trip (N+1 against SQLite).
-        // once the repositories expose them. Today the per-event GetAsync round-trip is acceptable
-        // because anomaly volumes are bounded (1 row per suspension interval per event).
         var distinctEventIds = anomalies.Select(a => a.EventId).Distinct().ToList();
 
-        var eventLookup = new Dictionary<DomainEventId, Event>(distinctEventIds.Count);
+        var eventLookup = await _events.GetManyAsync(distinctEventIds, ct).ConfigureAwait(false);
-        var resultLookup = new Dictionary<DomainEventId, EventResult>(distinctEventIds.Count);
+        var resultLookup = await _results.GetManyAsync(distinctEventIds, ct).ConfigureAwait(false);
-        var eventTitles = new Dictionary<DomainEventId, string>(distinctEventIds.Count);
-        foreach (var id in distinctEventIds)
-        {
-            ct.ThrowIfCancellationRequested();
 
-            var ev = await _events.GetAsync(id, ct).ConfigureAwait(false);
+        var eventTitles = new Dictionary<DomainEventId, string>(eventLookup.Count);
-            if (ev is not null)
+        foreach (var (id, ev) in eventLookup)
-            {
+            eventTitles[id] = ev.Title;
-                eventLookup[id] = ev;
-                eventTitles[id] = string.Concat(ev.Side1Name, " vs ", ev.Side2Name);
-            }
-
-            var res = await _results.GetAsync(id, ct).ConfigureAwait(false);
-            if (res is not null) resultLookup[id] = res;
-        }
 
         // Evaluate every anomaly through the pure domain function.
         var resolved = new List<ResolvedAnomaly>();

src/Marathon.Application/UseCases/PullResultsUseCase.cs

@@ -72,10 +72,10 @@ public sealed class PullResultsUseCase
         IResultRepository resultRepo,
         ILogger<PullResultsUseCase> logger)
     {
-        _scraper    = scraper    ?? throw new ArgumentNullException(nameof(scraper));
+        _scraper = scraper ?? throw new ArgumentNullException(nameof(scraper));
-        _eventRepo  = eventRepo  ?? throw new ArgumentNullException(nameof(eventRepo));
+        _eventRepo = eventRepo ?? throw new ArgumentNullException(nameof(eventRepo));
         _resultRepo = resultRepo ?? throw new ArgumentNullException(nameof(resultRepo));
-        _logger     = logger     ?? throw new ArgumentNullException(nameof(logger));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
     }
 
     /// <summary>
@@ -149,12 +149,13 @@ public sealed class PullResultsUseCase
     {
         if (selection is { Count: > 0 })
         {
+            // Batched load (was N+1); preserve the caller's selection order and
+            // silently drop ids with no stored event.
+            var events = await _eventRepo.GetManyAsync(selection, ct).ConfigureAwait(false);
             var resolved = new List<Event>(selection.Count);
             foreach (var id in selection)
             {
-                ct.ThrowIfCancellationRequested();
+                if (events.TryGetValue(id, out var ev))
-                var ev = await _eventRepo.GetAsync(id, ct).ConfigureAwait(false);
-                if (ev is not null)
                     resolved.Add(ev);
             }
             return resolved;

src/Marathon.Application/UseCases/RunBacktestUseCase.cs

@@ -63,29 +63,16 @@ public sealed class RunBacktestUseCase
             return BacktestSimulator.Run(strategy, Array.Empty<BacktestCandidate>());
         }
 
-        // Distinct event lookups — minimises repo calls.
+        // Batched lookups — a single query each, replacing the prior per-event
-        // TODO (perf, future): batch via IEventRepository.GetManyAsync /
+        // GetAsync round-trip (N+1 against SQLite).
-        // IResultRepository.GetManyAsync once those exist — currently shared
-        // with EvaluateAnomalyOutcomesUseCase, acceptable at expected volumes.
         var distinctEventIds = anomalies.Select(a => a.EventId).Distinct().ToList();
 
-        var eventLookup = new Dictionary<DomainEventId, Event>(distinctEventIds.Count);
+        var eventLookup = await _events.GetManyAsync(distinctEventIds, ct).ConfigureAwait(false);
-        var resultLookup = new Dictionary<DomainEventId, EventResult>(distinctEventIds.Count);
+        var resultLookup = await _results.GetManyAsync(distinctEventIds, ct).ConfigureAwait(false);
-        var titles = new Dictionary<DomainEventId, string>(distinctEventIds.Count);
-        foreach (var id in distinctEventIds)
-        {
-            ct.ThrowIfCancellationRequested();
 
-            var ev = await _events.GetAsync(id, ct).ConfigureAwait(false);
+        var titles = new Dictionary<DomainEventId, string>(eventLookup.Count);
-            if (ev is not null)
+        foreach (var (id, ev) in eventLookup)
-            {
+            titles[id] = ev.Title;
-                eventLookup[id] = ev;
-                titles[id] = string.Concat(ev.Side1Name, " vs ", ev.Side2Name);
-            }
-
-            var res = await _results.GetAsync(id, ct).ConfigureAwait(false);
-            if (res is not null) resultLookup[id] = res;
-        }
 
         var candidates = new List<BacktestCandidate>(anomalies.Count);
         foreach (var anomaly in anomalies)

src/Marathon.Domain/Entities/Event.cs

@@ -63,4 +63,11 @@ public sealed record Event(
     /// numeric event ID.
     /// </remarks>
     public string? EventPath { get; init; }
+
+    /// <summary>
+    /// Display title in the canonical "{Side1Name} vs {Side2Name}" form. Single
+    /// source for the home-vs-away join that was previously duplicated across the
+    /// report use cases and list/feed services.
+    /// </summary>
+    public string Title => $"{Side1Name} vs {Side2Name}";
 }

src/Marathon.Infrastructure/Migrations/20260528000000_AddSnapshotCapturedAtIndexes.cs

@@ -0,0 +1,43 @@
+using Marathon.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Marathon.Infrastructure.Migrations;
+
+/// <inheritdoc />
+[DbContext(typeof(MarathonDbContext))]
+[Migration("20260528000000_AddSnapshotCapturedAtIndexes")]
+public partial class AddSnapshotCapturedAtIndexes : Migration
+{
+    /// <inheritdoc />
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        // Composite index for the dominant read shape: filter by EventCode + a
+        // CapturedAt range, frequently with ORDER BY CapturedAt. Lets SQLite serve
+        // both the predicate and the ordering from the index rather than scanning.
+        migrationBuilder.CreateIndex(
+            name: "IX_Snapshots_EventCode_CapturedAt",
+            table: "Snapshots",
+            columns: new[] { "EventCode", "CapturedAt" });
+
+        // Covers GetLatestPreMatchAsync: EventCode + Source filter, ORDER BY CapturedAt DESC.
+        migrationBuilder.CreateIndex(
+            name: "IX_Snapshots_EventCode_Source_CapturedAt",
+            table: "Snapshots",
+            columns: new[] { "EventCode", "Source", "CapturedAt" });
+    }
+
+    /// <inheritdoc />
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.DropIndex(
+            name: "IX_Snapshots_EventCode_Source_CapturedAt",
+            table: "Snapshots");
+
+        migrationBuilder.DropIndex(
+            name: "IX_Snapshots_EventCode_CapturedAt",
+            table: "Snapshots");
+    }
+}

src/Marathon.Infrastructure/Migrations/MarathonDbContextModelSnapshot.cs

@@ -92,6 +92,8 @@ partial class MarathonDbContextModelSnapshot : ModelSnapshot
             b.Property<int>("Source").HasColumnType("INTEGER");
             b.HasKey("Id");
             b.HasIndex("EventCode").HasDatabaseName("IX_Snapshots_EventCode");
+            b.HasIndex("EventCode", "CapturedAt").HasDatabaseName("IX_Snapshots_EventCode_CapturedAt");
+            b.HasIndex("EventCode", "Source", "CapturedAt").HasDatabaseName("IX_Snapshots_EventCode_Source_CapturedAt");
             b.ToTable("Snapshots");
         });
 

src/Marathon.Infrastructure/Persistence/Configurations/SnapshotConfiguration.cs

@@ -18,6 +18,17 @@ internal sealed class SnapshotConfiguration : IEntityTypeConfiguration<SnapshotE
 
         builder.HasIndex(s => s.EventCode).HasDatabaseName("IX_Snapshots_EventCode");
 
+        // Snapshots is the largest table (live cadence 5–10s, 90-day retention) and
+        // every hot read filters EventCode + CapturedAt range, often with an ORDER BY
+        // CapturedAt. These composite indexes let SQLite satisfy the filter and the
+        // ordering from the index instead of scanning + sorting the table.
+        builder.HasIndex(s => new { s.EventCode, s.CapturedAt })
+            .HasDatabaseName("IX_Snapshots_EventCode_CapturedAt");
+
+        // Covers GetLatestPreMatchAsync: EventCode + Source filter, ORDER BY CapturedAt DESC.
+        builder.HasIndex(s => new { s.EventCode, s.Source, s.CapturedAt })
+            .HasDatabaseName("IX_Snapshots_EventCode_Source_CapturedAt");
+
         builder.HasMany(s => s.Bets)
             .WithOne(b => b.Snapshot)
             .HasForeignKey(b => b.SnapshotId)

src/Marathon.Infrastructure/Persistence/Mapping.cs

@@ -1,4 +1,3 @@
-using System.Globalization;
 using Marathon.Domain.Entities;
 using Marathon.Domain.Enums;
 using Marathon.Domain.ValueObjects;
@@ -10,16 +9,15 @@ namespace Marathon.Infrastructure.Persistence;
 /// Mapping helpers that translate between domain objects and EF Core persistence entities.
 /// Domain invariants are enforced on the domain side; mapping is purely structural.
 /// </summary>
+/// <remarks>
+/// ScheduledAt / CapturedAt / DetectedAt / CompletedAt / PlacedAt are encoded and
+/// decoded exclusively through <see cref="SqliteDateText"/> so the write format and
+/// the repositories' range-predicate format can never drift apart.
+/// </remarks>
 internal static class Mapping
 {
-    // ScheduledAt / CapturedAt / DetectedAt / CompletedAt are written via
-    // DateTimeOffset.ToString("O") — round-trip ISO 8601. Parse with the
-    // invariant culture and RoundtripKind so a non-en-US thread culture
-    // (or a future locale change) cannot corrupt the round-trip.
-    private const DateTimeStyles RoundtripStyles = DateTimeStyles.RoundtripKind;
-
     // ─── Bet scope discriminator constants ────────────────────────────────────
-    private const int ScopeMatch  = 0;
+    private const int ScopeMatch = 0;
     private const int ScopePeriod = 1;
     // ─── Event ───────────────────────────────────────────────────────────────
 
@@ -31,7 +29,7 @@ internal static class Mapping
             CountryCode = domain.CountryCode,
             LeagueId = domain.LeagueId,
             Category = domain.Category,
-            ScheduledAt = domain.ScheduledAt.ToString("O"),
+            ScheduledAt = SqliteDateText.Key(domain.ScheduledAt),
             Side1Name = domain.Side1Name,
             Side2Name = domain.Side2Name,
             EventPath = domain.EventPath,
@@ -44,7 +42,7 @@ internal static class Mapping
             CountryCode: entity.CountryCode,
             LeagueId: entity.LeagueId,
             Category: entity.Category,
-            ScheduledAt: DateTimeOffset.Parse(entity.ScheduledAt, CultureInfo.InvariantCulture, RoundtripStyles),
+            ScheduledAt: SqliteDateText.Parse(entity.ScheduledAt),
             Side1Name: entity.Side1Name,
             Side2Name: entity.Side2Name)
         {
@@ -57,7 +55,7 @@ internal static class Mapping
         new()
         {
             EventCode = domain.EventId.Value,
-            CapturedAt = domain.CapturedAt.ToString("O"),
+            CapturedAt = SqliteDateText.Key(domain.CapturedAt),
             Source = (int)domain.Source,
             Bets = domain.Bets.Select(ToEntity).ToList(),
         };
@@ -65,7 +63,7 @@ internal static class Mapping
     public static OddsSnapshot ToDomain(SnapshotEntity entity) =>
         new(
             eventId: new EventId(entity.EventCode),
-            capturedAt: DateTimeOffset.Parse(entity.CapturedAt, CultureInfo.InvariantCulture, RoundtripStyles),
+            capturedAt: SqliteDateText.Parse(entity.CapturedAt),
             source: (OddsSource)entity.Source,
             bets: entity.Bets.Select(ToDomain).ToList().AsReadOnly());
 
@@ -86,7 +84,7 @@ internal static class Mapping
     {
         var scope = entity.Scope switch
         {
-            ScopeMatch  => (BetScope)MatchScope.Instance,
+            ScopeMatch => (BetScope)MatchScope.Instance,
             ScopePeriod => new PeriodScope(entity.PeriodNumber!.Value),
             _ => throw new InvalidOperationException(
                 $"Unknown BetScope discriminator: {entity.Scope}"),
@@ -109,7 +107,7 @@ internal static class Mapping
             Side1Score = domain.Side1Score,
             Side2Score = domain.Side2Score,
             WinnerSide = (int)domain.WinnerSide,
-            CompletedAt = domain.CompletedAt.ToString("O"),
+            CompletedAt = SqliteDateText.Key(domain.CompletedAt),
         };
 
     public static EventResult ToDomain(EventResultEntity entity) =>
@@ -118,7 +116,7 @@ internal static class Mapping
             Side1Score: entity.Side1Score,
             Side2Score: entity.Side2Score,
             WinnerSide: (Side)entity.WinnerSide,
-            CompletedAt: DateTimeOffset.Parse(entity.CompletedAt, CultureInfo.InvariantCulture, RoundtripStyles));
+            CompletedAt: SqliteDateText.Parse(entity.CompletedAt));
 
     // ─── Anomaly ──────────────────────────────────────────────────────────────
 
@@ -127,7 +125,7 @@ internal static class Mapping
         {
             Id = domain.Id.ToString(),
             EventCode = domain.EventId.Value,
-            DetectedAt = domain.DetectedAt.ToString("O"),
+            DetectedAt = SqliteDateText.Key(domain.DetectedAt),
             Kind = (int)domain.Kind,
             Score = domain.Score,
             EvidenceJson = domain.EvidenceJson,
@@ -137,7 +135,7 @@ internal static class Mapping
         new(
             Id: Guid.Parse(entity.Id),
             EventId: new EventId(entity.EventCode),
-            DetectedAt: DateTimeOffset.Parse(entity.DetectedAt, CultureInfo.InvariantCulture, RoundtripStyles),
+            DetectedAt: SqliteDateText.Parse(entity.DetectedAt),
             Kind: (AnomalyKind)entity.Kind,
             Score: entity.Score,
             EvidenceJson: entity.EvidenceJson);
@@ -172,7 +170,7 @@ internal static class Mapping
             Value = domain.Selection.Value?.Value,
             Rate = domain.Selection.Rate.Value,
             Stake = domain.Stake,
-            PlacedAt = domain.PlacedAt.ToString("O"),
+            PlacedAt = SqliteDateText.Key(domain.PlacedAt),
             Outcome = (int)domain.Outcome,
             Notes = domain.Notes,
         };
@@ -181,7 +179,7 @@ internal static class Mapping
     {
         var scope = entity.Scope switch
         {
-            ScopeMatch  => (BetScope)MatchScope.Instance,
+            ScopeMatch => (BetScope)MatchScope.Instance,
             ScopePeriod => new PeriodScope(entity.PeriodNumber!.Value),
             _ => throw new InvalidOperationException(
                 $"Unknown BetScope discriminator: {entity.Scope}"),
@@ -198,7 +196,7 @@ internal static class Mapping
             EventId: new EventId(entity.EventCode),
             Selection: selection,
             Stake: entity.Stake,
-            PlacedAt: DateTimeOffset.Parse(entity.PlacedAt, CultureInfo.InvariantCulture, RoundtripStyles),
+            PlacedAt: SqliteDateText.Parse(entity.PlacedAt),
             Outcome: (BetOutcome)entity.Outcome,
             Notes: entity.Notes);
     }

src/Marathon.Infrastructure/Persistence/Repositories/AnomalyRepository.cs

@@ -23,6 +23,44 @@ internal sealed class AnomalyRepository : IAnomalyRepository
         return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
     }
 
+    public async Task<int> CountSinceAsync(DateTimeOffset since, CancellationToken ct = default)
+    {
+        // Server-side COUNT(*) — the unread-badge hot path must not materialise the
+        // whole table (with EvidenceJson) just to count. DetectedAt is stored as the
+        // O-format TEXT key (see SqliteDateText); ">" matches the prior in-memory
+        // GetUnreadCountAsync semantics (strictly newer than the last-seen marker).
+        var sinceStr = SqliteDateText.Key(since);
+        return await _db.Anomalies.AsNoTracking()
+            .Where(a => a.DetectedAt.CompareTo(sinceStr) > 0)
+            .CountAsync(ct);
+    }
+
+    public async Task<IReadOnlyList<Anomaly>> ListByDateRangeAsync(
+        DateTimeOffset? from,
+        DateTimeOffset? to,
+        CancellationToken ct = default)
+    {
+        var q = _db.Anomalies.AsNoTracking();
+
+        if (from is { } f)
+        {
+            var fromStr = SqliteDateText.Key(f);
+            q = q.Where(a => a.DetectedAt.CompareTo(fromStr) >= 0);
+        }
+
+        if (to is { } t)
+        {
+            var toStr = SqliteDateText.Key(t);
+            q = q.Where(a => a.DetectedAt.CompareTo(toStr) <= 0);
+        }
+
+        var entities = await q
+            .OrderByDescending(a => a.DetectedAt)
+            .ToListAsync(ct);
+
+        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
+    }
+
     public async Task AddAsync(Anomaly entity, CancellationToken ct = default)
     {
         var efEntity = Mapping.ToEntity(entity);

src/Marathon.Infrastructure/Persistence/Repositories/EventRepository.cs

@@ -26,9 +26,10 @@ internal sealed class EventRepository : IEventRepository
 
     public async Task<IReadOnlyList<Event>> ListByDateRangeAsync(DateRange range, CancellationToken ct = default)
     {
-        // ScheduledAt is stored as ISO 8601 TEXT; SQLite TEXT comparison sorts correctly for ISO 8601.
+        // ScheduledAt is stored as ISO 8601 TEXT (see SqliteDateText); SQLite TEXT
-        var fromStr = range.From.ToString("O");
+        // comparison sorts chronologically for the fixed-offset O format.
-        var toStr = range.To.ToString("O");
+        var fromStr = SqliteDateText.Key(range.From);
+        var toStr = SqliteDateText.Key(range.To);
 
         // EF Core SQLite cannot translate string.Compare(...) with StringComparison; it can
         // translate the relational operators on string columns (which use BINARY/ordinal
@@ -41,6 +42,57 @@ internal sealed class EventRepository : IEventRepository
         return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
     }
 
+    public async Task<IReadOnlyList<Event>> QueryAsync(EventQuery query, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(query);
+
+        var fromStr = SqliteDateText.Key(query.Dates.From);
+        var toStr = SqliteDateText.Key(query.Dates.To);
+
+        // Date range + sport filter pushed to SQL so a multi-sport page no longer
+        // materialises every event in the window. The composite
+        // IX_Events_SportCode_ScheduledAt index covers this predicate. Case-sensitive
+        // search / country filtering and locale-aware sorting stay in the service
+        // layer where Cyrillic ordinal semantics are preserved.
+        var q = _db.Events.AsNoTracking()
+            .Where(e => e.ScheduledAt.CompareTo(fromStr) >= 0
+                     && e.ScheduledAt.CompareTo(toStr) <= 0);
+
+        if (query.SportCodes is { Count: > 0 } sports)
+        {
+            var sportArray = sports.Distinct().ToArray();
+            q = q.Where(e => sportArray.Contains(e.SportCode));
+        }
+
+        var entities = await q.ToListAsync(ct);
+        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
+    }
+
+    public async Task<IReadOnlyDictionary<EventId, Event>> GetManyAsync(
+        IReadOnlyCollection<EventId> ids,
+        CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(ids);
+
+        var result = new Dictionary<EventId, Event>(ids.Count);
+        if (ids.Count == 0)
+            return result;
+
+        var codes = ids.Select(e => e.Value).Distinct().ToArray();
+
+        var entities = await _db.Events.AsNoTracking()
+            .Where(e => codes.Contains(e.EventCode))
+            .ToListAsync(ct);
+
+        foreach (var entity in entities)
+        {
+            var domain = Mapping.ToDomain(entity);
+            result[domain.Id] = domain;
+        }
+
+        return result;
+    }
+
     public async Task<IReadOnlyList<Event>> ListBySportAsync(SportCode sport, CancellationToken ct = default)
     {
         var entities = await _db.Events.AsNoTracking()
@@ -50,6 +102,9 @@ internal sealed class EventRepository : IEventRepository
         return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
     }
 
+    public Task<int> CountAsync(CancellationToken ct = default) =>
+        _db.Events.AsNoTracking().CountAsync(ct);
+
     public async Task<IReadOnlyList<int>> ListDistinctSportCodesAsync(CancellationToken ct = default)
     {
         var codes = await _db.Events.AsNoTracking()

src/Marathon.Infrastructure/Persistence/Repositories/ResultRepository.cs

@@ -23,6 +23,31 @@ internal sealed class ResultRepository : IResultRepository
         return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
     }
 
+    public async Task<IReadOnlyDictionary<EventId, EventResult>> GetManyAsync(
+        IReadOnlyCollection<EventId> ids,
+        CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(ids);
+
+        var result = new Dictionary<EventId, EventResult>(ids.Count);
+        if (ids.Count == 0)
+            return result;
+
+        var codes = ids.Select(e => e.Value).Distinct().ToArray();
+
+        var entities = await _db.EventResults.AsNoTracking()
+            .Where(r => codes.Contains(r.EventCode))
+            .ToListAsync(ct);
+
+        foreach (var entity in entities)
+        {
+            var domain = Mapping.ToDomain(entity);
+            result[domain.EventId] = domain;
+        }
+
+        return result;
+    }
+
     public async Task AddAsync(EventResult entity, CancellationToken ct = default)
     {
         var efEntity = Mapping.ToEntity(entity);

src/Marathon.Infrastructure/Persistence/Repositories/SnapshotRepository.cs

@@ -19,14 +19,22 @@ internal sealed class SnapshotRepository : ISnapshotRepository
         return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
     }
 
+    public Task<int> CountSinceAsync(DateTimeOffset since, CancellationToken ct = default)
+    {
+        var sinceStr = SqliteDateText.Key(since);
+        return _db.Snapshots.AsNoTracking()
+            .Where(s => s.CapturedAt.CompareTo(sinceStr) >= 0)
+            .CountAsync(ct);
+    }
+
     public async Task<IReadOnlyList<OddsSnapshot>> ListByEventAsync(
         EventId eventId,
         DateTimeOffset from,
         DateTimeOffset to,
         CancellationToken ct = default)
     {
-        var fromStr = from.ToString("O");
+        var fromStr = SqliteDateText.Key(from);
-        var toStr = to.ToString("O");
+        var toStr = SqliteDateText.Key(to);
 
         var entities = await _db.Snapshots.AsNoTracking()
             .Include(s => s.Bets)
@@ -51,8 +59,8 @@ internal sealed class SnapshotRepository : ISnapshotRepository
             return result;
 
         var ids = eventIds.Select(e => e.Value).Distinct().ToArray();
-        var fromStr = from.ToString("O");
+        var fromStr = SqliteDateText.Key(from);
-        var toStr = to.ToString("O");
+        var toStr = SqliteDateText.Key(to);
 
         var entities = await _db.Snapshots.AsNoTracking()
             .Include(s => s.Bets)
@@ -93,7 +101,7 @@ internal sealed class SnapshotRepository : ISnapshotRepository
         // expression EF-translatable (the IL would otherwise carry a cast).
         const int preMatchSource = (int)Marathon.Domain.Enums.OddsSource.PreMatch;
 
-        var toStr = atOrBefore.ToString("O");
+        var toStr = SqliteDateText.Key(atOrBefore);
 
         var entity = await _db.Snapshots.AsNoTracking()
             .Include(s => s.Bets)

src/Marathon.Infrastructure/Persistence/SqliteDateText.cs

@@ -0,0 +1,42 @@
+using System.Globalization;
+
+namespace Marathon.Infrastructure.Persistence;
+
+/// <summary>
+/// Single source of truth for how <see cref="DateTimeOffset"/> values are encoded
+/// as the TEXT used by both the write path (<see cref="Mapping"/>) and the
+/// date-range predicates / ORDER BY clauses in the repositories.
+/// </summary>
+/// <remarks>
+/// <para>
+/// Dates are stored as round-trip ISO-8601 (<c>"O"</c> format) TEXT. SQLite TEXT
+/// columns use BINARY (ordinal) collation by default, so the relational operators
+/// (<c>&gt;=</c>, <c>&lt;=</c>) and <c>ORDER BY</c> on these strings sort
+/// <b>chronologically</b> — but ONLY because every persisted timestamp carries the
+/// same Moscow <c>+03:00</c> offset (see the project invariant in CLAUDE.md). Two
+/// instants written with different offsets would sort lexically, not
+/// chronologically, and silently corrupt range filtering.
+/// </para>
+/// <para>
+/// Centralising the format here means the write encoding and the query-bound
+/// encoding can never drift apart, and the offset invariant is documented in one
+/// authoritative place. If a future change normalises storage to UTC or a native
+/// DATETIME column, this is the only call site that must change.
+/// </para>
+/// </remarks>
+internal static class SqliteDateText
+{
+    // Parse with the invariant culture + RoundtripKind so a non-en-US thread
+    // culture (or a future locale change) cannot corrupt the round-trip.
+    private const DateTimeStyles RoundtripStyles = DateTimeStyles.RoundtripKind;
+
+    /// <summary>
+    /// Encodes a <see cref="DateTimeOffset"/> as the TEXT key used for storage and
+    /// for the bounds of range/ordering predicates.
+    /// </summary>
+    public static string Key(DateTimeOffset value) => value.ToString("O");
+
+    /// <summary>Decodes a stored TEXT key back into a <see cref="DateTimeOffset"/>.</summary>
+    public static DateTimeOffset Parse(string text) =>
+        DateTimeOffset.Parse(text, CultureInfo.InvariantCulture, RoundtripStyles);
+}

src/Marathon.Infrastructure/Workers/LiveOddsPoller.cs

@@ -28,8 +28,8 @@ internal sealed class LiveOddsPoller : BackgroundService
         ILogger<LiveOddsPoller> logger)
     {
         _services = services ?? throw new ArgumentNullException(nameof(services));
-        _opts     = opts     ?? throw new ArgumentNullException(nameof(opts));
+        _opts = opts ?? throw new ArgumentNullException(nameof(opts));
-        _logger   = logger   ?? throw new ArgumentNullException(nameof(logger));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
     }
 
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
@@ -47,6 +47,8 @@ internal sealed class LiveOddsPoller : BackgroundService
                 continue;
             }
 
+            var cycleStart = DateTime.UtcNow;
+
             try
             {
                 await using var scope = _services.CreateAsyncScope();
@@ -69,9 +71,17 @@ internal sealed class LiveOddsPoller : BackgroundService
             var interval = TimeSpan.FromSeconds(
                 Math.Max(1, _opts.CurrentValue.LivePollIntervalSeconds));
 
+            // Budget the sleep against the time the cycle already consumed so the
+            // effective cadence tracks the configured interval instead of
+            // (interval + scrapeDuration). If a cycle overran the interval, loop
+            // immediately rather than sleeping a full extra interval.
+            var remaining = interval - (DateTime.UtcNow - cycleStart);
+            if (remaining <= TimeSpan.Zero)
+                continue;
+
             try
             {
-                await Task.Delay(interval, stoppingToken);
+                await Task.Delay(remaining, stoppingToken);
             }
             catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
             {

src/Marathon.UI/Services/AnomalyBrowsingService.cs

@@ -28,10 +28,12 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
     {
         ArgumentNullException.ThrowIfNull(filter);
 
-        var all = await _anomalies.ListAsync(ct).ConfigureAwait(false);
+        // Date filter pushed to SQL; severity needs the parsed score and sport needs
+        // the event join, so those two stay in memory over the smaller returned set.
+        var all = await _anomalies.ListByDateRangeAsync(filter.From, filter.To, ct).ConfigureAwait(false);
         if (all.Count == 0) return Array.Empty<AnomalyListItem>();
 
-        // Resolve event metadata in one pass — distinct EventIds only.
+        // Resolve event metadata in one batched pass — distinct EventIds only.
         var eventLookup = await BuildEventLookupAsync(all, ct).ConfigureAwait(false);
 
         var items = new List<AnomalyListItem>(all.Count);
@@ -44,7 +46,7 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
             }
         }
 
-        // Apply filters in-memory (small list, UI page).
+        // Remaining filters in-memory (page-sized set).
         IEnumerable<AnomalyListItem> filtered = items;
 
         if (filter.MinSeverity is { } minSeverity)
@@ -57,16 +59,6 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
             filtered = filtered.Where(i => sports.Contains(i.Sport.Value));
         }
 
-        if (filter.From is { } from)
-        {
-            filtered = filtered.Where(i => i.DetectedAt >= from);
-        }
-
-        if (filter.To is { } to)
-        {
-            filtered = filtered.Where(i => i.DetectedAt <= to);
-        }
-
         return filtered
             .OrderByDescending(static i => i.DetectedAt)
             .ToList();
@@ -88,16 +80,9 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
         return new AnomalyDetailVm(item, pre, post);
     }
 
-    public async Task<int> GetUnreadCountAsync(DateTimeOffset since, CancellationToken ct)
+    public Task<int> GetUnreadCountAsync(DateTimeOffset since, CancellationToken ct)
-    {
+        // Server-side COUNT(*) — no longer materialises the table to count.
-        var all = await _anomalies.ListAsync(ct).ConfigureAwait(false);
+        => _anomalies.CountSinceAsync(since, ct);
-        var count = 0;
-        foreach (var anomaly in all)
-        {
-            if (anomaly.DetectedAt > since) count++;
-        }
-        return count;
-    }
 
     public async Task<IReadOnlyList<int>> ListKnownSportCodesAsync(CancellationToken ct)
     {
@@ -125,14 +110,8 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
             .Distinct()
             .ToList();
 
-        var dict = new Dictionary<DomainEventId, Event>(distinct.Count);
+        // Single batched query instead of one GetAsync per distinct event (N+1).
-        foreach (var eid in distinct)
+        return await _events.GetManyAsync(distinct, ct).ConfigureAwait(false);
-        {
-            ct.ThrowIfCancellationRequested();
-            var ev = await _events.GetAsync(eid, ct).ConfigureAwait(false);
-            if (ev is not null) dict[eid] = ev;
-        }
-        return dict;
     }
 
     private static bool TryProject(
@@ -151,7 +130,7 @@ public sealed class AnomalyBrowsingService : IAnomalyBrowsingService
         var country = ev?.CountryCode ?? string.Empty;
         var league = ev?.LeagueId ?? string.Empty;
         var title = ev is not null
-            ? $"{ev.Side1Name} vs {ev.Side2Name}"
+            ? ev.Title
             : anomaly.EventId.Value;
 
         var preSnap = ToSnapshot(dto.PreSuspension);

src/Marathon.UI/Services/BetJournalService.cs

@@ -40,15 +40,15 @@ public sealed class BetJournalService : IBetJournalService
         if (report.Bets.Count == 0)
             return new BetJournalVm(report.Stats, Array.Empty<BetJournalRowVm>());
 
-        // Resolve event titles in one pass — distinct ids only.
+        // Resolve event titles in one batched query — distinct ids only (was N+1).
+        // Missing events (pruned by snapshot retention) fall back to the raw id.
         var distinctIds = report.Bets.Select(r => r.Bet.EventId).Distinct().ToList();
+        var events = await _events.GetManyAsync(distinctIds, ct).ConfigureAwait(false);
         var titles = new Dictionary<DomainEventId, string>(distinctIds.Count);
         foreach (var id in distinctIds)
         {
-            ct.ThrowIfCancellationRequested();
+            titles[id] = events.TryGetValue(id, out var ev)
-            var ev = await _events.GetAsync(id, ct).ConfigureAwait(false);
+                ? ev.Title
-            titles[id] = ev is not null
-                ? string.Concat(ev.Side1Name, " vs ", ev.Side2Name)
                 : id.Value;
         }
 

src/Marathon.UI/Services/EventBrowsingService.cs

@@ -83,15 +83,17 @@ public sealed class EventBrowsingService : IEventBrowsingService
     {
         ArgumentNullException.ThrowIfNull(filter);
 
-        var range = new DateRange(filter.Dates.From, filter.Dates.To);
+        // Date range + sport filter pushed to SQL (was: load the whole date range,
-        var events = await _events.ListByDateRangeAsync(range, ct).ConfigureAwait(false);
+        // then filter sports in memory). Country/search filtering and locale-aware
+        // sorting stay here to preserve the Cyrillic ordinal semantics that SQLite's
+        // BINARY collation would change.
+        var query = new EventQuery(
+            new DateRange(filter.Dates.From, filter.Dates.To),
+            filter.SportCodes);
+        var events = await _events.QueryAsync(query, ct).ConfigureAwait(false);
 
-        // Apply non-temporal filters in-memory — list size is small (UI page).
         IEnumerable<Event> filtered = events;
 
-        if (filter.SportCodes is { Count: > 0 } sports)
-            filtered = filtered.Where(e => sports.Contains(e.Sport.Value));
-
         if (filter.CountryCodes is { Count: > 0 } countries)
             filtered = filtered.Where(e => countries.Contains(e.CountryCode, StringComparer.OrdinalIgnoreCase));
 

tests/Marathon.Application.Tests/UseCases/BuildBetJournalReportUseCaseTests.cs

@@ -19,6 +19,12 @@ public sealed class BuildBetJournalReportUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly ISnapshotRepository _snapshots = Substitute.For<ISnapshotRepository>();
 
+    public BuildBetJournalReportUseCaseTests()
+    {
+        // Use case batches event loads via GetManyAsync; route through per-id stubs.
+        TestFixtures.BridgeGetMany(_events);
+    }
+
     private BuildBetJournalReportUseCase CreateSut() =>
         new(_bets, _events, _snapshots, NullLogger<BuildBetJournalReportUseCase>.Instance);
 

tests/Marathon.Application.Tests/UseCases/EvaluateAnomalyOutcomesUseCaseTests.cs

@@ -22,6 +22,14 @@ public sealed class EvaluateAnomalyOutcomesUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly IResultRepository _results = Substitute.For<IResultRepository>();
 
+    public EvaluateAnomalyOutcomesUseCaseTests()
+    {
+        // Use cases batch event/result loads via GetManyAsync; route those through
+        // the per-id GetAsync stubs each test already configures.
+        TestFixtures.BridgeGetMany(_events);
+        TestFixtures.BridgeGetMany(_results);
+    }
+
     private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
     private static readonly DateTimeOffset BaseTime =
         new(2026, 5, 10, 18, 0, 0, MoscowOffset);
@@ -287,6 +295,36 @@ public sealed class EvaluateAnomalyOutcomesUseCaseTests
         report.EventTitles[id].Should().Be("Team A vs Team B");
     }
 
+    [Fact]
+    public async Task Should_BatchEventAndResultLoads_InsteadOfPerIdGetAsync()
+    {
+        // Regression guard for the N+1 fix: the use case must resolve events/results
+        // via the batched GetManyAsync, never the per-id GetAsync in a loop. We stub
+        // GetManyAsync directly (overriding the constructor bridge) so DidNotReceive()
+        // on GetAsync is meaningful.
+        var id1 = new EventId("11111111");
+        var id2 = new EventId("22222222");
+
+        _anomalies.ListAsync(Arg.Any<CancellationToken>())
+            .Returns(new[] { MakeAnomaly(id1, 0.55m), MakeAnomaly(id2, 0.55m) }.ToList().AsReadOnly());
+
+        _events.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(new Dictionary<EventId, Event> { [id1] = MakeEvent(id1, 11), [id2] = MakeEvent(id2, 6) });
+        _results.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(new Dictionary<EventId, EventResult>());
+
+        await CreateSut().ExecuteAsync(CancellationToken.None);
+
+        await _events.Received(1)
+            .GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>());
+        await _events.DidNotReceive()
+            .GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>());
+        await _results.Received(1)
+            .GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>());
+        await _results.DidNotReceive()
+            .GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>());
+    }
+
     [Fact]
     public async Task Should_HandleMissingEvent_By_OmittingFromSportBuckets()
     {

tests/Marathon.Application.Tests/UseCases/PullResultsUseCaseTests.cs

@@ -17,6 +17,13 @@ public sealed class PullResultsUseCaseTests
     private readonly IEventRepository _eventRepo = Substitute.For<IEventRepository>();
     private readonly IResultRepository _resultRepo = Substitute.For<IResultRepository>();
 
+    public PullResultsUseCaseTests()
+    {
+        // Selection-mode candidate resolution now batches via GetManyAsync; route
+        // it through the per-id GetAsync stubs each test configures.
+        TestFixtures.BridgeGetMany(_eventRepo);
+    }
+
     private static readonly DateRange AnyRange = new(
         DateTimeOffset.UtcNow.AddDays(-1),
         DateTimeOffset.UtcNow);

tests/Marathon.Application.Tests/UseCases/RunBacktestUseCaseTests.cs

@@ -25,6 +25,13 @@ public sealed class RunBacktestUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly IResultRepository _results = Substitute.For<IResultRepository>();
 
+    public RunBacktestUseCaseTests()
+    {
+        // Use case batches event/result loads via GetManyAsync; route through per-id stubs.
+        TestFixtures.BridgeGetMany(_events);
+        TestFixtures.BridgeGetMany(_results);
+    }
+
     private RunBacktestUseCase CreateSut() =>
         new(_anomalies, _events, _results, NullLogger<RunBacktestUseCase>.Instance);
 

tests/Marathon.Application.Tests/UseCases/TestFixtures.cs

@@ -1,8 +1,10 @@
+using Marathon.Application.Abstractions;
 using Marathon.Application.Configuration;
 using Marathon.Domain.Entities;
 using Marathon.Domain.Enums;
 using Marathon.Domain.ValueObjects;
 using Microsoft.Extensions.Options;
+using NSubstitute;
 
 namespace Marathon.Application.Tests.UseCases;
 
@@ -13,6 +15,45 @@ internal static class TestFixtures
 {
     private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
 
+    /// <summary>
+    /// Bridges the legacy per-id <c>GetAsync</c> stubs to the batched
+    /// <c>GetManyAsync</c> the use cases now call: each requested id is resolved
+    /// through whatever <c>GetAsync</c> was configured to return for it. Lets the
+    /// existing per-id <c>.Returns(...)</c> setups keep working unchanged.
+    /// </summary>
+    public static void BridgeGetMany(IEventRepository events)
+    {
+        events.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(ci =>
+            {
+                var ids = ci.Arg<IReadOnlyCollection<EventId>>();
+                var dict = new Dictionary<EventId, Event>();
+                foreach (var id in ids.Distinct())
+                {
+                    var ev = events.GetAsync(id, CancellationToken.None).GetAwaiter().GetResult();
+                    if (ev is not null) dict[id] = ev;
+                }
+                return (IReadOnlyDictionary<EventId, Event>)dict;
+            });
+    }
+
+    /// <inheritdoc cref="BridgeGetMany(IEventRepository)"/>
+    public static void BridgeGetMany(IResultRepository results)
+    {
+        results.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(ci =>
+            {
+                var ids = ci.Arg<IReadOnlyCollection<EventId>>();
+                var dict = new Dictionary<EventId, EventResult>();
+                foreach (var id in ids.Distinct())
+                {
+                    var r = results.GetAsync(id, CancellationToken.None).GetAwaiter().GetResult();
+                    if (r is not null) dict[id] = r;
+                }
+                return (IReadOnlyDictionary<EventId, EventResult>)dict;
+            });
+    }
+
     /// <summary>Creates a minimal valid <see cref="Event"/> with the given event ID string.</summary>
     public static Event MakeEvent(string eventIdValue = "12345678")
     {

tests/Marathon.UI.Tests/Pages/Results/ResultsLoaderTests.cs

@@ -32,6 +32,21 @@ public sealed class ResultsLoaderTests : MarathonTestContext
             sp.GetRequiredService<IEventRepository>(),
             sp.GetRequiredService<IResultRepository>(),
             NullLogger<PullResultsUseCase>.Instance));
+
+        // PullResultsUseCase batches selection-mode candidate resolution via
+        // GetManyAsync; route it through whatever GetAsync the test configures.
+        _eventRepo.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(ci =>
+            {
+                var ids = ci.Arg<IReadOnlyCollection<EventId>>();
+                var dict = new Dictionary<EventId, Event>();
+                foreach (var id in ids.Distinct())
+                {
+                    var ev = _eventRepo.GetAsync(id, CancellationToken.None).GetAwaiter().GetResult();
+                    if (ev is not null) dict[id] = ev;
+                }
+                return (IReadOnlyDictionary<EventId, Event>)dict;
+            });
     }
 
     [Fact]