Drop the never-written warning/critical_behind_threshold columns (#5173)

docs/events/projections/async-daemon.md

@@ -642,9 +642,8 @@ that just emits and update every time that Marten has to "skip" stale events.
 
 ## Extended Progression Tracking
 
-Extended progression tracking adds ten monitoring columns (`heartbeat`,
-`agent_status`, `pause_reason`, `running_on_node`, `warning_behind_threshold`,
-`critical_behind_threshold`, `failure_category`, `failure_event_sequence`,
+Extended progression tracking adds eight monitoring columns (`heartbeat`,
+`agent_status`, `pause_reason`, `running_on_node`, `failure_category`, `failure_event_sequence`,
 `failure_event_type`, `failure_event_tenant_id`) to `mt_event_progression`. The async daemon writes
 them from existing runtime state and the shard-state selector reads them back
 into `ShardState` so monitoring tooling such as CritterWatch can display

src/DaemonTests/Bugs/Bug_5173_behind_threshold_columns_removed.cs

@@ -0,0 +1,63 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using JasperFx.Events;
+using Marten.Testing;
+using Marten.Testing.Harness;
+using Npgsql;
+using Shouldly;
+using Weasel.Postgresql;
+using Xunit;
+
+namespace DaemonTests.Bugs;
+
+/// <summary>
+/// #5173 — <c>warning_behind_threshold</c> and <c>critical_behind_threshold</c> were created in DDL,
+/// listed in every extended-tracking SELECT, and hydrated onto <c>ShardState</c> — and written by
+/// nothing, in any repo. Every read returned NULL, always. They are gone; what is left is a pin that
+/// removing two columns from the middle of a positional selector did not shift the ordinals of the
+/// <c>failure_*</c> columns that follow them.
+/// </summary>
+public class Bug_5173_behind_threshold_columns_removed: OneOffConfigurationsContext
+{
+    [Fact]
+    public async Task the_threshold_columns_are_no_longer_created()
+    {
+        StoreOptions(x => x.Events.EnableExtendedProgressionTracking = true);
+        await theStore.EnsureStorageExistsAsync(typeof(IEvent));
+
+        var columns = await progressionColumnsAsync();
+
+        columns.ShouldNotContain("warning_behind_threshold");
+        columns.ShouldNotContain("critical_behind_threshold");
+
+        // ...and the eight columns that carry something are untouched.
+        foreach (var expected in new[]
+                 {
+                     "heartbeat", "agent_status", "pause_reason", "running_on_node", "failure_category",
+                     "failure_event_sequence", "failure_event_type", "failure_event_tenant_id"
+                 })
+        {
+            columns.ShouldContain(expected);
+        }
+    }
+
+    private async Task<List<string>> progressionColumnsAsync()
+    {
+        await using var conn = new NpgsqlConnection(ConnectionSource.ConnectionString);
+        await conn.OpenAsync(TestContext.Current.CancellationToken);
+
+        await using var reader = await conn
+            .CreateCommand(
+                "select column_name from information_schema.columns where table_schema = :schema and table_name = 'mt_event_progression'")
+            .With("schema", theStore.Events.DatabaseSchemaName, NpgsqlTypes.NpgsqlDbType.Varchar)
+            .ExecuteReaderAsync(TestContext.Current.CancellationToken);
+
+        var names = new List<string>();
+        while (await reader.ReadAsync(TestContext.Current.CancellationToken))
+        {
+            names.Add(reader.GetString(0));
+        }
+
+        return names;
+    }
+}

src/Marten/Events/Daemon/Progress/ProjectionProgressStatement.cs

@@ -41,7 +41,7 @@ protected override void configure(ICommandBuilder builder)
         // #5048 / jasperfx#565: the failure_* columns trail the existing extended block so the ordinals
         // ShardStateSelector walks stay stable.
         const string extendedColumns =
-            "heartbeat, agent_status, pause_reason, running_on_node, warning_behind_threshold, critical_behind_threshold, failure_category, failure_event_sequence, failure_event_type, failure_event_tenant_id";
+            "heartbeat, agent_status, pause_reason, running_on_node, failure_category, failure_event_sequence, failure_event_type, failure_event_tenant_id";
 
         if (_events.UseOptimizedProjectionRebuilds && _events.EnableExtendedProgressionTracking)
         {

src/Marten/Events/Daemon/Progress/ShardStateSelector.cs

@@ -72,17 +72,9 @@ public async Task<ShardState> ResolveAsync(DbDataReader reader, CancellationToke
             }
             nextIndex++;
 
-            if (!await reader.IsDBNullAsync(nextIndex, token).ConfigureAwait(false))
-            {
-                state.WarningBehindThreshold = await reader.GetFieldValueAsync<long>(nextIndex, token).ConfigureAwait(false);
-            }
-            nextIndex++;
-
-            if (!await reader.IsDBNullAsync(nextIndex, token).ConfigureAwait(false))
-            {
-                state.CriticalBehindThreshold = await reader.GetFieldValueAsync<long>(nextIndex, token).ConfigureAwait(false);
-            }
-            nextIndex++;
+            // #5173: WarningBehindThreshold / CriticalBehindThreshold were hydrated here from two
+            // columns nothing ever wrote. The properties remain on JasperFx's ShardState (unassigned
+            // and unread there too) until they are removed upstream.
 
             // #5048 / jasperfx#565: rehydrate the classified failure so a consumer polling the database
             // (CritterWatch when the publishing node is down) gets the same shape as a live ShardState

src/Marten/Events/Schema/EventProgressionTable.cs

@@ -50,8 +50,14 @@ public EventProgressionTable(EventGraph eventGraph): base(new PostgresqlObjectNa
             AddColumn("agent_status", "varchar(20)").AllowNulls();
             AddColumn("pause_reason", "text").AllowNulls();
             AddColumn("running_on_node", "integer").AllowNulls();
-            AddColumn("warning_behind_threshold", "bigint").AllowNulls();
-            AddColumn("critical_behind_threshold", "bigint").AllowNulls();
+
+            // #5173: warning_behind_threshold / critical_behind_threshold used to be created here.
+            // They were created, selected and hydrated onto ShardState -- and written by nothing, in
+            // any repo, so every read of them returned NULL. Two columns of storage, two entries in
+            // every extended-tracking SELECT and two selector ordinals, carrying nothing. Removed
+            // rather than wired: nothing ever owned the value. Existing deployments get an
+            // `alter table ... drop column` on their next apply, which is lossless because the
+            // columns were provably always NULL.
 
             // #5048 / jasperfx#565: the classified reason this shard is paused or stopped, so a consumer
             // polling the database (CritterWatch when the publishing node is DOWN, which is exactly when