Fabric monitoring

Monitoring & diagnostics

Query Labels

SELECT ... FROM ...
OPTION (LABEL = 'PROJECT_Module_Description');

Labels appear in queryinsights.exec_requests_history.label. Use for tracking, filtering, and performance analysis.

Query Insights (30-day retention)

View	Purpose
queryinsights.exec_requests_history	Every completed query: status, duration, CPU, data scanned
queryinsights.exec_sessions_history	Session history: login info, times
queryinsights.long_running_queries	Aggregated: median vs last-run time
queryinsights.frequently_run_queries	Run counts, execution times for recurring patterns

Gotcha: Data appears with up to 15 minutes delay. After creating a new warehouse, views may return "Invalid object name" — wait ~2 minutes.

Top Expensive Queries

SELECT TOP 10
    distributed_statement_id, query_hash, label,
    total_elapsed_time_ms, allocated_cpu_time_ms,
    data_scanned_remote_storage_mb, result_cache_hit
FROM queryinsights.exec_requests_history
ORDER BY allocated_cpu_time_ms DESC;

Aggregate by query_hash over the last 7 days to find recurring expensive patterns.

DMVs (Live State)

DMV	Shows	Min Role
sys.dm_exec_connections	Active connections (session_id, client_address)	Admin only
sys.dm_exec_sessions	Authenticated sessions (login_name, login_time, status)	All roles (own sessions)
sys.dm_exec_requests	Active requests (command, start_time, total_elapsed_time)	All roles (own requests)

-- Find long-running queries
SELECT request_id, session_id, command, start_time, total_elapsed_time, status
FROM sys.dm_exec_requests
WHERE status = 'running'
ORDER BY total_elapsed_time DESC;

-- Identify the user
SELECT login_name FROM sys.dm_exec_sessions WHERE session_id = <id>;

-- Kill a runaway query (Admin only)
KILL '<session_id>';

SQL Endpoint Metadata Sync (new sync — Preview, May 2026)

Diagnose slow/stale Lakehouse SQLEP reads when queries return data older than what has landed. On endpoints created under the new metadata-sync preview (opt-in, new endpoints only):

-- Inspect per-table sync freshness and blocked state
SELECT last_update_time_utc, latest_log_version, latest_checkpoint_version, is_blocked
FROM sys.dm_db_external_tables_log_status;   -- is_blocked: 1 = last update blocked, 0 = succeeded

-- Force a targeted refresh of one table's data (data-only changes)
EXEC sys.sp_dw_refresh_ext_table 'dbo.<table>';

Schema changes (add/drop tables or columns, type changes) need the full-item Refresh SQL endpoint metadata REST API instead. Full preview note — enablement, architecture, limitations — lives in the fabric-spark skill; the slow-SQLEP gotcha cross-references it in the fabric-gotchas skill.

Result Set Caching (Preview)

result_cache_hit field in exec_requests_history: 1 = cache hit, 0 = miss, negative values = reason caching was skipped. Non-deterministic functions (GETDATE(), NEWID()) prevent caching. Cache auto-invalidates when underlying data changes.

Statistics

Auto-maintained for single-column histograms, average column length, and table cardinality. Manual CREATE STATISTICS / UPDATE STATISTICS available.

Gotcha: After a rolled-back transaction containing a large INSERT, auto-generated statistics can be inaccurate. Run UPDATE STATISTICS manually on affected columns to recover.

Reference

• Microsoft Learn: Monitor Fabric Data Warehouse (overview)
• Microsoft Learn: Query insights in Fabric Data Warehouse
• Microsoft Learn: Use query labels in Fabric Data Warehouse
• Comprehensive MS Learn link bundle (per-view T-SQL refs / DMVs / capacity throttling / workspace monitoring): references/REFERENCE.md

See also

• fabric-warehouse skill — T-SQL authoring rules for the queries you're monitoring
• fabric-gotchas skill — cross-cutting error index