Issue #281 Gap 4: Remove session_wait_stats (zero UI, full removal)

Remove collect.session_wait_stats entirely — table, collector procedure,
reporting view, schedule entries, schema metadata, CI checks, and all
references. This collector had 12 columns and zero UI in either app.

Adds cleanup DROPs to 02_create_tables.sql so existing installations
get cleaned up on upgrade (drops view, procedure, table, schedule row).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: erikdarlingdata

.github/sql/ci_validate_installation.sql

@@ -30,7 +30,7 @@ IF SCHEMA_ID(N'report')  IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: sche
 PRINT '';
 
 /*
-Procedures in collect schema (37)
+Procedures in collect schema (36)
 */
 PRINT 'Checking collect procedures...';
 
@@ -65,7 +65,6 @@ IF OBJECT_ID(N'collect.tempdb_stats_collector', N'P')           IS NULL BEGIN SE
 IF OBJECT_ID(N'collect.plan_cache_stats_collector', N'P')       IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.plan_cache_stats_collector'; END;       SET @checked += 1;
 IF OBJECT_ID(N'collect.session_stats_collector', N'P')          IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.session_stats_collector'; END;          SET @checked += 1;
 IF OBJECT_ID(N'collect.waiting_tasks_collector', N'P')          IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.waiting_tasks_collector'; END;          SET @checked += 1;
-IF OBJECT_ID(N'collect.session_wait_stats_collector', N'P')     IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.session_wait_stats_collector'; END;     SET @checked += 1;
 IF OBJECT_ID(N'collect.server_configuration_collector', N'P')   IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.server_configuration_collector'; END;   SET @checked += 1;
 IF OBJECT_ID(N'collect.database_configuration_collector', N'P') IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.database_configuration_collector'; END; SET @checked += 1;
 IF OBJECT_ID(N'collect.configuration_issues_analyzer', N'P')    IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: collect.configuration_issues_analyzer'; END;    SET @checked += 1;
@@ -142,7 +141,6 @@ IF OBJECT_ID(N'report.blocking_chain_analysis', N'V')             IS NULL BEGIN
 IF OBJECT_ID(N'report.tempdb_contention_analysis', N'V')          IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.tempdb_contention_analysis'; END;          SET @checked += 1;
 IF OBJECT_ID(N'report.parameter_sensitivity_detection', N'V')     IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.parameter_sensitivity_detection'; END;     SET @checked += 1;
 IF OBJECT_ID(N'report.scheduler_cpu_analysis', N'V')              IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.scheduler_cpu_analysis'; END;              SET @checked += 1;
-IF OBJECT_ID(N'report.session_wait_analysis', N'V')               IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.session_wait_analysis'; END;               SET @checked += 1;
 IF OBJECT_ID(N'report.critical_issues', N'V')                     IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.critical_issues'; END;                     SET @checked += 1;
 IF OBJECT_ID(N'report.memory_usage_trends', N'V')                 IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.memory_usage_trends'; END;                 SET @checked += 1;
 IF OBJECT_ID(N'report.running_jobs', N'V')                        IS NULL BEGIN SET @missing += 1; PRINT '  MISSING: report.running_jobs'; END;                        SET @checked += 1;
@@ -182,7 +180,7 @@ WHERE OBJECT_SCHEMA_NAME(t.object_id) = N'config';
 PRINT '  collect schema tables: ' + CONVERT(varchar(10), @collect_tables);
 PRINT '  config schema tables: ' + CONVERT(varchar(10), @config_tables);
 
-IF @collect_tables < 20 BEGIN SET @missing += 1; PRINT '  MISSING: expected >= 20 collect tables, found ' + CONVERT(varchar(10), @collect_tables); END; SET @checked += 1;
+IF @collect_tables < 19 BEGIN SET @missing += 1; PRINT '  MISSING: expected >= 20 collect tables, found ' + CONVERT(varchar(10), @collect_tables); END; SET @checked += 1;
 IF @config_tables < 5  BEGIN SET @missing += 1; PRINT '  MISSING: expected >= 5 config tables, found ' + CONVERT(varchar(10), @config_tables); END;  SET @checked += 1;
 
 PRINT '';

Dashboard/schema/tables.json

@@ -677,26 +677,5 @@
       "row_count": { "type": "bigint", "nullable": true }
     },
     "primary_key": ["collection_id"]
-  },
-  "collect.session_wait_stats": {
-    "description": "Per-session wait statistics from sys.dm_exec_session_wait_stats (SQL 2016 SP1+)",
-    "columns": {
-      "collection_id": { "type": "bigint", "nullable": false, "identity": true },
-      "collection_time": { "type": "datetime2(7)", "nullable": false },
-      "session_id": { "type": "integer", "nullable": false },
-      "wait_type": { "type": "nvarchar(60)", "nullable": false },
-      "waiting_tasks_count": { "type": "bigint", "nullable": false },
-      "wait_time_ms": { "type": "bigint", "nullable": false },
-      "max_wait_time_ms": { "type": "bigint", "nullable": false },
-      "signal_wait_time_ms": { "type": "bigint", "nullable": false },
-      "database_id": { "type": "integer", "nullable": true },
-      "database_name": { "type": "sysname", "nullable": true },
-      "login_name": { "type": "nvarchar(128)", "nullable": true },
-      "host_name": { "type": "nvarchar(128)", "nullable": true },
-      "program_name": { "type": "nvarchar(128)", "nullable": true },
-      "sql_handle": { "type": "varbinary(64)", "nullable": true },
-      "query_text": { "type": "nvarchar(max)", "nullable": true }
-    },
-    "primary_key": ["collection_id"]
   }
 }

install/02_create_tables.sql

@@ -18,6 +18,15 @@ GO
 USE PerformanceMonitor;
 GO
 
+/*
+Cleanup: session_wait_stats removed in v1.4
+*/
+IF OBJECT_ID(N'report.session_wait_analysis', N'V') IS NOT NULL DROP VIEW report.session_wait_analysis;
+IF OBJECT_ID(N'collect.session_wait_stats_collector', N'P') IS NOT NULL DROP PROCEDURE collect.session_wait_stats_collector;
+IF OBJECT_ID(N'collect.session_wait_stats', N'U') IS NOT NULL DROP TABLE collect.session_wait_stats;
+IF OBJECT_ID(N'config.collection_schedule', N'U') IS NOT NULL DELETE FROM config.collection_schedule WHERE collector_name = N'session_wait_stats_collector';
+GO
+
 /*
 Collection tables for the 7 core collectors
 */
@@ -1277,49 +1286,6 @@ BEGIN
     PRINT 'Created collect.waiting_tasks table';
 END;
 
-/*
-Table: collect.session_wait_stats
-Purpose: Captures per-session wait statistics from sys.dm_exec_session_wait_stats
-Collection Frequency: Every 60 seconds (alongside query snapshots)
-Type: Snapshot (resets on session end)
-Dependencies: None
-Notes: Correlates with query_snapshots to show waits for specific sessions
-       Requires SQL Server 2016 SP1 or later
-*/
-IF OBJECT_ID(N'collect.session_wait_stats', N'U') IS NULL
-BEGIN
-    CREATE TABLE
-        collect.session_wait_stats
-    (
-        collection_id bigint IDENTITY NOT NULL,
-        collection_time datetime2(7) NOT NULL
-            DEFAULT SYSDATETIME(),
-        session_id integer NOT NULL,
-        wait_type nvarchar(60) NOT NULL,
-        waiting_tasks_count bigint NOT NULL,
-        wait_time_ms bigint NOT NULL,
-        max_wait_time_ms bigint NOT NULL,
-        signal_wait_time_ms bigint NOT NULL,
-        /*Session context for correlation*/
-        database_id integer NULL,
-        database_name sysname NULL,
-        login_name nvarchar(128) NULL,
-        host_name nvarchar(128) NULL,
-        program_name nvarchar(128) NULL,
-        /*Query context if executing*/
-        sql_handle varbinary(64) NULL,
-        query_text nvarchar(max) NULL,
-        CONSTRAINT
-            PK_session_wait_stats
-        PRIMARY KEY CLUSTERED
-            (collection_time, collection_id)
-        WITH
-            (DATA_COMPRESSION = PAGE)
-    );
-
-    PRINT 'Created collect.session_wait_stats table';
-END;
-
 /*
 Running Jobs Monitor (Point-in-Time Snapshot)
 Captures currently running SQL Agent jobs with historical duration comparison

install/03_create_config_tables.sql

@@ -202,7 +202,6 @@ BEGIN
                 (N'plan_cache_stats_collector', 1, 60, 5, 30, N'Plan cache composition statistics - single-use plans and plan cache bloat detection'),
                 (N'session_stats_collector', 1, 5, 2, 30, N'Session and connection statistics - connection leaks and application patterns'),
                 (N'waiting_tasks_collector', 1, 5, 2, 30, N'Currently waiting tasks - blocking chains and wait analysis'),
-                (N'session_wait_stats_collector', 1, 1, 2, 30, N'Per-session wait statistics - correlates waits with specific sessions/queries (requires SQL Server 2016 SP1+)'),
                 (N'running_jobs_collector', 1, 5, 2, 7, N'Currently running SQL Agent jobs with historical duration comparison');
 
             /*

install/04_create_schedule_table.sql

@@ -74,7 +74,6 @@ FROM
     (N'plan_cache_stats_collector', 1, 5, 5, 30, N'Plan cache composition statistics - single-use plans and plan cache bloat detection'),
     (N'session_stats_collector', 1, 1, 2, 30, N'Session and connection statistics - connection leaks and application patterns'),
     (N'waiting_tasks_collector', 1, 1, 2, 30, N'Currently waiting tasks - blocking chains and wait analysis'),
-    (N'session_wait_stats_collector', 1, 1, 2, 30, N'Per-session wait statistics - correlates waits with specific sessions/queries (requires SQL Server 2016 SP1+)'),
     (N'running_jobs_collector', 1, 1, 2, 7, N'Currently running SQL Agent jobs with historical duration comparison')
 ) AS v (collector_name, enabled, frequency_minutes, max_duration_minutes, retention_days, description)
 WHERE NOT EXISTS

install/06_ensure_collection_table.sql

@@ -1054,38 +1054,6 @@ BEGIN
                     (DATA_COMPRESSION = PAGE)
             );
 
-        END;
-        ELSE IF @table_name = N'session_wait_stats'
-        BEGIN
-            CREATE TABLE
-                collect.session_wait_stats
-            (
-                collection_id bigint IDENTITY NOT NULL,
-                collection_time datetime2(7) NOT NULL
-                    DEFAULT SYSDATETIME(),
-                session_id integer NOT NULL,
-                wait_type nvarchar(60) NOT NULL,
-                waiting_tasks_count bigint NOT NULL,
-                wait_time_ms bigint NOT NULL,
-                max_wait_time_ms bigint NOT NULL,
-                signal_wait_time_ms bigint NOT NULL,
-                /*Session context for correlation*/
-                database_id integer NULL,
-                database_name sysname NULL,
-                login_name nvarchar(128) NULL,
-                host_name nvarchar(128) NULL,
-                program_name nvarchar(128) NULL,
-                /*Query context if executing*/
-                sql_handle varbinary(64) NULL,
-                query_text nvarchar(max) NULL,
-                CONSTRAINT
-                    PK_session_wait_stats
-                PRIMARY KEY CLUSTERED
-                    (collection_time, collection_id)
-                WITH
-                    (DATA_COMPRESSION = PAGE)
-            );
-
         END;
         ELSE IF @table_name = N'running_jobs'
         BEGIN
@@ -1117,7 +1085,7 @@ BEGIN
         END;
         ELSE
         BEGIN
-            SET @error_message = N'Unknown table name: ' + @table_name + N'. Valid table names are: wait_stats, query_stats, memory_stats, memory_pressure_events, deadlock_xml, blocked_process_xml, procedure_stats, query_snapshots, query_store_data, trace_analysis, default_trace_events, file_io_stats, memory_grant_stats, cpu_scheduler_stats, memory_clerks_stats, perfmon_stats, cpu_utilization_stats, blocking_deadlock_stats, latch_stats, spinlock_stats, tempdb_stats, plan_cache_stats, session_stats, waiting_tasks, session_wait_stats, running_jobs';
+            SET @error_message = N'Unknown table name: ' + @table_name + N'. Valid table names are: wait_stats, query_stats, memory_stats, memory_pressure_events, deadlock_xml, blocked_process_xml, procedure_stats, query_snapshots, query_store_data, trace_analysis, default_trace_events, file_io_stats, memory_grant_stats, cpu_scheduler_stats, memory_clerks_stats, perfmon_stats, cpu_utilization_stats, blocking_deadlock_stats, latch_stats, spinlock_stats, tempdb_stats, plan_cache_stats, session_stats, waiting_tasks, running_jobs';
             RAISERROR(@error_message, 16, 1);
             RETURN;
         END;