sprints and audit work

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Models/SchedulerLogEntry.cs

@@ -1,56 +0,0 @@
-// <copyright file="SchedulerLogEntry.cs" company="StellaOps">
-// Copyright (c) StellaOps. Licensed under AGPL-3.0-or-later.
-// </copyright>
-
-namespace StellaOps.Scheduler.Persistence.Postgres.Models;
-
-/// <summary>
-/// Represents an HLC-ordered, chain-linked scheduler log entry.
-/// </summary>
-public sealed record SchedulerLogEntry
-{
-    /// <summary>
-    /// Storage sequence number (not authoritative for ordering).
-    /// </summary>
-    public long SeqBigint { get; init; }
-
-    /// <summary>
-    /// Tenant identifier.
-    /// </summary>
-    public required string TenantId { get; init; }
-
-    /// <summary>
-    /// HLC timestamp in sortable string format.
-    /// </summary>
-    public required string THlc { get; init; }
-
-    /// <summary>
-    /// Optional queue partition key.
-    /// </summary>
-    public string PartitionKey { get; init; } = string.Empty;
-
-    /// <summary>
-    /// Job identifier (deterministic from payload).
-    /// </summary>
-    public required Guid JobId { get; init; }
-
-    /// <summary>
-    /// SHA-256 hash of the canonical payload JSON.
-    /// </summary>
-    public required byte[] PayloadHash { get; init; }
-
-    /// <summary>
-    /// Previous chain link (null for first entry in chain).
-    /// </summary>
-    public byte[]? PrevLink { get; init; }
-
-    /// <summary>
-    /// Chain link: Hash(prev_link || job_id || t_hlc || payload_hash).
-    /// </summary>
-    public required byte[] Link { get; init; }
-
-    /// <summary>
-    /// Timestamp when the entry was created.
-    /// </summary>
-    public DateTimeOffset CreatedAt { get; init; }
-}

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Repositories/ISchedulerLogRepository.cs

@@ -49,6 +49,38 @@ public interface ISchedulerLogRepository
         string? endTHlc,
         CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// Gets log entries within an HLC range with additional filtering.
+    /// </summary>
+    /// <param name="tenantId">Tenant identifier.</param>
+    /// <param name="startTHlc">Start HLC (inclusive, null for no lower bound).</param>
+    /// <param name="endTHlc">End HLC (inclusive, null for no upper bound).</param>
+    /// <param name="limit">Maximum entries to return (0 for no limit).</param>
+    /// <param name="partitionKey">Optional partition key filter.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task<IReadOnlyList<SchedulerLogEntity>> GetByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        int limit,
+        string? partitionKey,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Gets log entries after a given HLC timestamp.
+    /// </summary>
+    /// <param name="tenantId">Tenant identifier.</param>
+    /// <param name="afterTHlc">Start after this HLC (exclusive).</param>
+    /// <param name="limit">Maximum entries to return.</param>
+    /// <param name="partitionKey">Optional partition key filter.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task<IReadOnlyList<SchedulerLogEntity>> GetAfterHlcAsync(
+        string tenantId,
+        string afterTHlc,
+        int limit,
+        string? partitionKey = null,
+        CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Gets a log entry by job ID.
     /// </summary>
@@ -71,4 +103,31 @@ public interface ISchedulerLogRepository
         string? startTHlc,
         string? endTHlc,
         CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Counts entries in an HLC range with partition filter.
+    /// </summary>
+    /// <param name="tenantId">Tenant identifier.</param>
+    /// <param name="startTHlc">Start HLC (inclusive, null for no lower bound).</param>
+    /// <param name="endTHlc">End HLC (inclusive, null for no upper bound).</param>
+    /// <param name="partitionKey">Optional partition key filter.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task<int> CountByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        string? partitionKey,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Checks if a job entry already exists for idempotency.
+    /// </summary>
+    /// <param name="tenantId">Tenant identifier.</param>
+    /// <param name="jobId">Job identifier.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>True if job exists.</returns>
+    Task<bool> ExistsAsync(
+        string tenantId,
+        Guid jobId,
+        CancellationToken cancellationToken = default);
 }

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Repositories/PostgresBatchSnapshotRepository.cs

@@ -23,7 +23,7 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
     }
 
     /// <inheritdoc />
-    public async Task InsertAsync(BatchSnapshot snapshot, CancellationToken cancellationToken = default)
+    public async Task InsertAsync(BatchSnapshotEntity snapshot, CancellationToken cancellationToken = default)
     {
         const string sql = """
             INSERT INTO scheduler.batch_snapshot (
@@ -53,7 +53,7 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
     }
 
     /// <inheritdoc />
-    public async Task<BatchSnapshot?> GetByIdAsync(Guid batchId, CancellationToken cancellationToken = default)
+    public async Task<BatchSnapshotEntity?> GetByIdAsync(Guid batchId, CancellationToken cancellationToken = default)
     {
         const string sql = """
             SELECT batch_id, tenant_id, range_start_t, range_end_t, head_link,
@@ -72,7 +72,40 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
     }
 
     /// <inheritdoc />
-    public async Task<BatchSnapshot?> GetLatestAsync(string tenantId, CancellationToken cancellationToken = default)
+    public async Task<IReadOnlyList<BatchSnapshotEntity>> GetByTenantAsync(
+        string tenantId,
+        int limit = 100,
+        CancellationToken cancellationToken = default)
+    {
+        const string sql = """
+            SELECT batch_id, tenant_id, range_start_t, range_end_t, head_link,
+                   job_count, created_at, signed_by, signature
+            FROM scheduler.batch_snapshot
+            WHERE tenant_id = @tenant_id
+            ORDER BY created_at DESC
+            LIMIT @limit
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        AddParameter(command, "limit", limit);
+
+        var snapshots = new List<BatchSnapshotEntity>();
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+
+        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+        {
+            snapshots.Add(MapSnapshot(reader));
+        }
+
+        return snapshots;
+    }
+
+    /// <inheritdoc />
+    public async Task<BatchSnapshotEntity?> GetLatestAsync(string tenantId, CancellationToken cancellationToken = default)
     {
         const string sql = """
             SELECT batch_id, tenant_id, range_start_t, range_end_t, head_link,
@@ -93,46 +126,7 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
     }
 
     /// <inheritdoc />
-    public async Task<IReadOnlyList<BatchSnapshot>> GetByTimeRangeAsync(
-        string tenantId,
-        DateTimeOffset startTime,
-        DateTimeOffset endTime,
-        int limit = 100,
-        CancellationToken cancellationToken = default)
-    {
-        const string sql = """
-            SELECT batch_id, tenant_id, range_start_t, range_end_t, head_link,
-                   job_count, created_at, signed_by, signature
-            FROM scheduler.batch_snapshot
-            WHERE tenant_id = @tenant_id
-              AND created_at >= @start_time
-              AND created_at <= @end_time
-            ORDER BY created_at DESC
-            LIMIT @limit
-            """;
-
-        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
-            .ConfigureAwait(false);
-        await using var command = CreateCommand(sql, connection);
-
-        AddParameter(command, "tenant_id", tenantId);
-        AddParameter(command, "start_time", startTime);
-        AddParameter(command, "end_time", endTime);
-        AddParameter(command, "limit", limit);
-
-        var snapshots = new List<BatchSnapshot>();
-        await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
-
-        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
-        {
-            snapshots.Add(MapSnapshot(reader));
-        }
-
-        return snapshots;
-    }
-
-    /// <inheritdoc />
-    public async Task<IReadOnlyList<BatchSnapshot>> GetContainingHlcAsync(
+    public async Task<IReadOnlyList<BatchSnapshotEntity>> GetContainingHlcAsync(
         string tenantId,
         string tHlc,
         CancellationToken cancellationToken = default)
@@ -154,7 +148,7 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
         AddParameter(command, "tenant_id", tenantId);
         AddParameter(command, "t_hlc", tHlc);
 
-        var snapshots = new List<BatchSnapshot>();
+        var snapshots = new List<BatchSnapshotEntity>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
 
         while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
@@ -165,9 +159,9 @@ public sealed class PostgresBatchSnapshotRepository : RepositoryBase<SchedulerDa
         return snapshots;
     }
 
-    private static BatchSnapshot MapSnapshot(NpgsqlDataReader reader)
+    private static BatchSnapshotEntity MapSnapshot(NpgsqlDataReader reader)
     {
-        return new BatchSnapshot
+        return new BatchSnapshotEntity
         {
             BatchId = reader.GetGuid(0),
             TenantId = reader.GetString(1),

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Repositories/PostgresChainHeadRepository.cs

@@ -46,13 +46,13 @@ public sealed class PostgresChainHeadRepository : RepositoryBase<SchedulerDataSo
     }
 
     /// <inheritdoc />
-    public async Task<ChainHead?> GetAsync(
+    public async Task<ChainHeadEntity?> GetAsync(
         string tenantId,
         string partitionKey,
         CancellationToken cancellationToken = default)
     {
         const string sql = """
-            SELECT tenant_id, partition_key, last_link, last_t_hlc, last_job_id, updated_at
+            SELECT tenant_id, partition_key, last_link, last_t_hlc, updated_at
             FROM scheduler.chain_heads
             WHERE tenant_id = @tenant_id AND partition_key = @partition_key
             """;
@@ -69,12 +69,45 @@ public sealed class PostgresChainHeadRepository : RepositoryBase<SchedulerDataSo
     }
 
     /// <inheritdoc />
-    public async Task<IReadOnlyList<ChainHead>> GetAllForTenantAsync(
+    public async Task<bool> UpsertAsync(
+        string tenantId,
+        string partitionKey,
+        byte[] newLink,
+        string newTHlc,
+        CancellationToken cancellationToken = default)
+    {
+        const string sql = """
+            INSERT INTO scheduler.chain_heads (tenant_id, partition_key, last_link, last_t_hlc, updated_at)
+            VALUES (@tenant_id, @partition_key, @last_link, @last_t_hlc, @updated_at)
+            ON CONFLICT (tenant_id, partition_key)
+            DO UPDATE SET
+                last_link = @last_link,
+                last_t_hlc = @last_t_hlc,
+                updated_at = @updated_at
+            WHERE scheduler.chain_heads.last_t_hlc < @last_t_hlc
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "writer", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        AddParameter(command, "partition_key", partitionKey);
+        AddParameter(command, "last_link", newLink);
+        AddParameter(command, "last_t_hlc", newTHlc);
+        AddParameter(command, "updated_at", DateTimeOffset.UtcNow);
+
+        var rowsAffected = await command.ExecuteNonQueryAsync(cancellationToken).ConfigureAwait(false);
+        return rowsAffected > 0;
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<ChainHeadEntity>> GetAllForTenantAsync(
         string tenantId,
         CancellationToken cancellationToken = default)
     {
         const string sql = """
-            SELECT tenant_id, partition_key, last_link, last_t_hlc, last_job_id, updated_at
+            SELECT tenant_id, partition_key, last_link, last_t_hlc, updated_at
             FROM scheduler.chain_heads
             WHERE tenant_id = @tenant_id
             ORDER BY partition_key
@@ -85,7 +118,7 @@ public sealed class PostgresChainHeadRepository : RepositoryBase<SchedulerDataSo
         await using var command = CreateCommand(sql, connection);
         AddParameter(command, "tenant_id", tenantId);
 
-        var heads = new List<ChainHead>();
+        var heads = new List<ChainHeadEntity>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
 
         while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
@@ -96,16 +129,15 @@ public sealed class PostgresChainHeadRepository : RepositoryBase<SchedulerDataSo
         return heads;
     }
 
-    private static ChainHead MapChainHead(NpgsqlDataReader reader)
+    private static ChainHeadEntity MapChainHead(NpgsqlDataReader reader)
     {
-        return new ChainHead
+        return new ChainHeadEntity
         {
             TenantId = reader.GetString(0),
             PartitionKey = reader.GetString(1),
             LastLink = reader.GetFieldValue<byte[]>(2),
             LastTHlc = reader.GetString(3),
-            LastJobId = reader.GetGuid(4),
-            UpdatedAt = reader.GetFieldValue<DateTimeOffset>(5)
+            UpdatedAt = reader.GetFieldValue<DateTimeOffset>(4)
         };
     }
 }

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Repositories/PostgresSchedulerLogRepository.cs

@@ -23,8 +23,8 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
     }
 
     /// <inheritdoc />
-    public async Task<long> InsertWithChainUpdateAsync(
-        SchedulerLogEntry entry,
+    public async Task<SchedulerLogEntity> InsertWithChainUpdateAsync(
+        SchedulerLogEntity entry,
         CancellationToken cancellationToken = default)
     {
         // Use the stored function for atomic insert + chain head update
@@ -53,11 +53,13 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
         AddParameter(command, "link", entry.Link);
 
         var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
-        return Convert.ToInt64(result);
+        var seqBigint = Convert.ToInt64(result);
+
+        return entry with { SeqBigint = seqBigint };
     }
 
     /// <inheritdoc />
-    public async Task<IReadOnlyList<SchedulerLogEntry>> GetByHlcOrderAsync(
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetByHlcOrderAsync(
         string tenantId,
         string? partitionKey,
         int limit,
@@ -92,7 +94,7 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
             AddParameter(command, "partition_key", partitionKey);
         }
 
-        var entries = new List<SchedulerLogEntry>();
+        var entries = new List<SchedulerLogEntity>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
 
         while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
@@ -104,12 +106,10 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
     }
 
     /// <inheritdoc />
-    public async Task<IReadOnlyList<SchedulerLogEntry>> GetByHlcRangeAsync(
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetByHlcRangeAsync(
         string tenantId,
         string? startTHlc,
         string? endTHlc,
-        int limit = 0,
-        string? partitionKey = null,
         CancellationToken cancellationToken = default)
     {
         var conditions = new List<string> { "tenant_id = @tenant_id" };
@@ -123,19 +123,12 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
             conditions.Add("t_hlc <= @end_t_hlc");
         }
 
-        if (partitionKey is not null)
-        {
-            conditions.Add("partition_key = @partition_key");
-        }
-
-        var limitClause = limit > 0 ? $"LIMIT {limit}" : string.Empty;
         var sql = $"""
             SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
                    payload_hash, prev_link, link, created_at
             FROM scheduler.scheduler_log
             WHERE {string.Join(" AND ", conditions)}
             ORDER BY t_hlc ASC
-            {limitClause}
             """;
 
         await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
@@ -153,12 +146,7 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
             AddParameter(command, "end_t_hlc", endTHlc);
         }
 
-        if (partitionKey is not null)
-        {
-            AddParameter(command, "partition_key", partitionKey);
-        }
-
-        var entries = new List<SchedulerLogEntry>();
+        var entries = new List<SchedulerLogEntity>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
 
         while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
@@ -170,52 +158,45 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
     }
 
     /// <inheritdoc />
-    public async Task<IReadOnlyList<SchedulerLogEntry>> GetAfterHlcAsync(
-        string tenantId,
-        string afterTHlc,
-        int limit,
-        string? partitionKey = null,
+    public async Task<SchedulerLogEntity?> GetByJobIdAsync(
+        Guid jobId,
         CancellationToken cancellationToken = default)
     {
-        var sql = partitionKey is null
-            ? """
-              SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
-                     payload_hash, prev_link, link, created_at
-              FROM scheduler.scheduler_log
-              WHERE tenant_id = @tenant_id AND t_hlc > @after_t_hlc
-              ORDER BY t_hlc ASC
-              LIMIT @limit
-              """
-            : """
-              SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
-                     payload_hash, prev_link, link, created_at
-              FROM scheduler.scheduler_log
-              WHERE tenant_id = @tenant_id AND t_hlc > @after_t_hlc AND partition_key = @partition_key
-              ORDER BY t_hlc ASC
-              LIMIT @limit
-              """;
+        const string sql = """
+            SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
+                   payload_hash, prev_link, link, created_at
+            FROM scheduler.scheduler_log
+            WHERE job_id = @job_id
+            """;
 
-        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+        await using var connection = await DataSource.OpenSystemConnectionAsync(cancellationToken)
             .ConfigureAwait(false);
         await using var command = CreateCommand(sql, connection);
+        AddParameter(command, "job_id", jobId);
 
-        AddParameter(command, "tenant_id", tenantId);
-        AddParameter(command, "after_t_hlc", afterTHlc);
-        AddParameter(command, "limit", limit);
-        if (partitionKey is not null)
-        {
-            AddParameter(command, "partition_key", partitionKey);
-        }
-
-        var entries = new List<SchedulerLogEntry>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+        return await reader.ReadAsync(cancellationToken).ConfigureAwait(false) ? MapEntry(reader) : null;
+    }
 
-        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
-        {
-            entries.Add(MapEntry(reader));
-        }
+    /// <inheritdoc />
+    public async Task<SchedulerLogEntity?> GetByLinkAsync(
+        byte[] link,
+        CancellationToken cancellationToken = default)
+    {
+        const string sql = """
+            SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
+                   payload_hash, prev_link, link, created_at
+            FROM scheduler.scheduler_log
+            WHERE link = @link
+            """;
 
-        return entries;
+        await using var connection = await DataSource.OpenSystemConnectionAsync(cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+        AddParameter(command, "link", link);
+
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+        return await reader.ReadAsync(cancellationToken).ConfigureAwait(false) ? MapEntry(reader) : null;
     }
 
     /// <inheritdoc />
@@ -223,7 +204,6 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
         string tenantId,
         string? startTHlc,
         string? endTHlc,
-        string? partitionKey = null,
         CancellationToken cancellationToken = default)
     {
         var conditions = new List<string> { "tenant_id = @tenant_id" };
@@ -237,11 +217,6 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
             conditions.Add("t_hlc <= @end_t_hlc");
         }
 
-        if (partitionKey is not null)
-        {
-            conditions.Add("partition_key = @partition_key");
-        }
-
         var sql = $"""
             SELECT COUNT(*)
             FROM scheduler.scheduler_log
@@ -263,6 +238,51 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
             AddParameter(command, "end_t_hlc", endTHlc);
         }
 
+        var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
+        return Convert.ToInt32(result);
+    }
+
+    /// <inheritdoc />
+    public async Task<int> CountByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        string? partitionKey,
+        CancellationToken cancellationToken = default)
+    {
+        var conditions = new List<string> { "tenant_id = @tenant_id" };
+        if (startTHlc is not null)
+        {
+            conditions.Add("t_hlc >= @start_t_hlc");
+        }
+        if (endTHlc is not null)
+        {
+            conditions.Add("t_hlc <= @end_t_hlc");
+        }
+        if (partitionKey is not null)
+        {
+            conditions.Add("partition_key = @partition_key");
+        }
+
+        var sql = $"""
+            SELECT COUNT(*)
+            FROM scheduler.scheduler_log
+            WHERE {string.Join(" AND ", conditions)}
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        if (startTHlc is not null)
+        {
+            AddParameter(command, "start_t_hlc", startTHlc);
+        }
+        if (endTHlc is not null)
+        {
+            AddParameter(command, "end_t_hlc", endTHlc);
+        }
         if (partitionKey is not null)
         {
             AddParameter(command, "partition_key", partitionKey);
@@ -273,24 +293,118 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
     }
 
     /// <inheritdoc />
-    public async Task<SchedulerLogEntry?> GetByJobIdAsync(
-        Guid jobId,
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        int limit,
+        string? partitionKey,
         CancellationToken cancellationToken = default)
     {
-        const string sql = """
+        var conditions = new List<string> { "tenant_id = @tenant_id" };
+        if (startTHlc is not null)
+        {
+            conditions.Add("t_hlc >= @start_t_hlc");
+        }
+        if (endTHlc is not null)
+        {
+            conditions.Add("t_hlc <= @end_t_hlc");
+        }
+        if (partitionKey is not null)
+        {
+            conditions.Add("partition_key = @partition_key");
+        }
+
+        var sql = $"""
             SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
                    payload_hash, prev_link, link, created_at
             FROM scheduler.scheduler_log
-            WHERE job_id = @job_id
+            WHERE {string.Join(" AND ", conditions)}
+            ORDER BY t_hlc ASC
+            {(limit > 0 ? "LIMIT @limit" : "")}
             """;
 
-        await using var connection = await DataSource.OpenSystemConnectionAsync(cancellationToken)
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
             .ConfigureAwait(false);
         await using var command = CreateCommand(sql, connection);
-        AddParameter(command, "job_id", jobId);
 
+        AddParameter(command, "tenant_id", tenantId);
+        if (startTHlc is not null)
+        {
+            AddParameter(command, "start_t_hlc", startTHlc);
+        }
+        if (endTHlc is not null)
+        {
+            AddParameter(command, "end_t_hlc", endTHlc);
+        }
+        if (partitionKey is not null)
+        {
+            AddParameter(command, "partition_key", partitionKey);
+        }
+        if (limit > 0)
+        {
+            AddParameter(command, "limit", limit);
+        }
+
+        var entries = new List<SchedulerLogEntity>();
         await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
-        return await reader.ReadAsync(cancellationToken).ConfigureAwait(false) ? MapEntry(reader) : null;
+
+        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+        {
+            entries.Add(MapEntry(reader));
+        }
+
+        return entries;
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetAfterHlcAsync(
+        string tenantId,
+        string afterTHlc,
+        int limit,
+        string? partitionKey = null,
+        CancellationToken cancellationToken = default)
+    {
+        var conditions = new List<string>
+        {
+            "tenant_id = @tenant_id",
+            "t_hlc > @after_t_hlc"
+        };
+        if (partitionKey is not null)
+        {
+            conditions.Add("partition_key = @partition_key");
+        }
+
+        var sql = $"""
+            SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id,
+                   payload_hash, prev_link, link, created_at
+            FROM scheduler.scheduler_log
+            WHERE {string.Join(" AND ", conditions)}
+            ORDER BY t_hlc ASC
+            LIMIT @limit
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        AddParameter(command, "after_t_hlc", afterTHlc);
+        AddParameter(command, "limit", limit);
+        if (partitionKey is not null)
+        {
+            AddParameter(command, "partition_key", partitionKey);
+        }
+
+        var entries = new List<SchedulerLogEntity>();
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+
+        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+        {
+            entries.Add(MapEntry(reader));
+        }
+
+        return entries;
     }
 
     /// <inheritdoc />
@@ -314,12 +428,12 @@ public sealed class PostgresSchedulerLogRepository : RepositoryBase<SchedulerDat
         AddParameter(command, "job_id", jobId);
 
         var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
-        return result is true;
+        return result is true or 1 or 1L;
     }
 
-    private static SchedulerLogEntry MapEntry(NpgsqlDataReader reader)
+    private static SchedulerLogEntity MapEntry(NpgsqlDataReader reader)
     {
-        return new SchedulerLogEntry
+        return new SchedulerLogEntity
         {
             SeqBigint = reader.GetInt64(0),
             TenantId = reader.GetString(1),

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/Postgres/Repositories/SchedulerLogRepository.cs

@@ -250,6 +250,177 @@ public sealed class SchedulerLogRepository : RepositoryBase<SchedulerDataSource>
         return result is int count ? count : 0;
     }
 
+    /// <inheritdoc />
+    public async Task<int> CountByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        string? partitionKey,
+        CancellationToken cancellationToken = default)
+    {
+        var whereClause = "WHERE tenant_id = @tenant_id";
+        if (startTHlc is not null)
+        {
+            whereClause += " AND t_hlc >= @start_t_hlc";
+        }
+        if (endTHlc is not null)
+        {
+            whereClause += " AND t_hlc <= @end_t_hlc";
+        }
+        if (partitionKey is not null)
+        {
+            whereClause += " AND partition_key = @partition_key";
+        }
+
+        var sql = $"""
+            SELECT COUNT(*)::INT
+            FROM scheduler.scheduler_log
+            {whereClause}
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        if (startTHlc is not null)
+        {
+            AddParameter(command, "start_t_hlc", startTHlc);
+        }
+        if (endTHlc is not null)
+        {
+            AddParameter(command, "end_t_hlc", endTHlc);
+        }
+        if (partitionKey is not null)
+        {
+            AddParameter(command, "partition_key", partitionKey);
+        }
+
+        var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
+        return result is int count ? count : 0;
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetByHlcRangeAsync(
+        string tenantId,
+        string? startTHlc,
+        string? endTHlc,
+        int limit,
+        string? partitionKey,
+        CancellationToken cancellationToken = default)
+    {
+        var whereClause = "WHERE tenant_id = @tenant_id";
+        if (startTHlc is not null)
+        {
+            whereClause += " AND t_hlc >= @start_t_hlc";
+        }
+        if (endTHlc is not null)
+        {
+            whereClause += " AND t_hlc <= @end_t_hlc";
+        }
+        if (partitionKey is not null)
+        {
+            whereClause += " AND partition_key = @partition_key";
+        }
+
+        var sql = $"""
+            SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id, payload_hash, prev_link, link, created_at
+            FROM scheduler.scheduler_log
+            {whereClause}
+            ORDER BY t_hlc ASC
+            {(limit > 0 ? "LIMIT @limit" : "")}
+            """;
+
+        return await QueryAsync(
+            tenantId,
+            sql,
+            cmd =>
+            {
+                AddParameter(cmd, "tenant_id", tenantId);
+                if (startTHlc is not null)
+                {
+                    AddParameter(cmd, "start_t_hlc", startTHlc);
+                }
+                if (endTHlc is not null)
+                {
+                    AddParameter(cmd, "end_t_hlc", endTHlc);
+                }
+                if (partitionKey is not null)
+                {
+                    AddParameter(cmd, "partition_key", partitionKey);
+                }
+                if (limit > 0)
+                {
+                    AddParameter(cmd, "limit", limit);
+                }
+            },
+            MapSchedulerLogEntry,
+            cancellationToken).ConfigureAwait(false);
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<SchedulerLogEntity>> GetAfterHlcAsync(
+        string tenantId,
+        string afterTHlc,
+        int limit,
+        string? partitionKey = null,
+        CancellationToken cancellationToken = default)
+    {
+        var whereClause = "WHERE tenant_id = @tenant_id AND t_hlc > @after_t_hlc";
+        if (partitionKey is not null)
+        {
+            whereClause += " AND partition_key = @partition_key";
+        }
+
+        var sql = $"""
+            SELECT seq_bigint, tenant_id, t_hlc, partition_key, job_id, payload_hash, prev_link, link, created_at
+            FROM scheduler.scheduler_log
+            {whereClause}
+            ORDER BY t_hlc ASC
+            LIMIT @limit
+            """;
+
+        return await QueryAsync(
+            tenantId,
+            sql,
+            cmd =>
+            {
+                AddParameter(cmd, "tenant_id", tenantId);
+                AddParameter(cmd, "after_t_hlc", afterTHlc);
+                AddParameter(cmd, "limit", limit);
+                if (partitionKey is not null)
+                {
+                    AddParameter(cmd, "partition_key", partitionKey);
+                }
+            },
+            MapSchedulerLogEntry,
+            cancellationToken).ConfigureAwait(false);
+    }
+
+    /// <inheritdoc />
+    public async Task<bool> ExistsAsync(
+        string tenantId,
+        Guid jobId,
+        CancellationToken cancellationToken = default)
+    {
+        const string sql = """
+            SELECT EXISTS(
+                SELECT 1 FROM scheduler.scheduler_log
+                WHERE tenant_id = @tenant_id AND job_id = @job_id
+            )
+            """;
+
+        await using var connection = await DataSource.OpenConnectionAsync(tenantId, "reader", cancellationToken)
+            .ConfigureAwait(false);
+        await using var command = CreateCommand(sql, connection);
+
+        AddParameter(command, "tenant_id", tenantId);
+        AddParameter(command, "job_id", jobId);
+
+        var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
+        return result is true or 1 or 1L;
+    }
+
     private static SchedulerLogEntity MapSchedulerLogEntry(NpgsqlDataReader reader)
     {
         return new SchedulerLogEntity

src/Scheduler/__Libraries/StellaOps.Scheduler.Persistence/StellaOps.Scheduler.Persistence.csproj

@@ -28,6 +28,7 @@
     <ProjectReference Include="..\..\..\__Libraries\StellaOps.Infrastructure.Postgres\StellaOps.Infrastructure.Postgres.csproj" />
     <ProjectReference Include="..\..\..\__Libraries\StellaOps.Infrastructure.EfCore\StellaOps.Infrastructure.EfCore.csproj" />
     <ProjectReference Include="..\..\..\__Libraries\StellaOps.HybridLogicalClock\StellaOps.HybridLogicalClock.csproj" />
+    <ProjectReference Include="..\..\..\__Libraries\StellaOps.Canonical.Json\StellaOps.Canonical.Json.csproj" />
   </ItemGroup>
 
   <!-- Embed SQL migrations as resources -->