This is the full AI Advice output returned directly in SSMS from:
EXEC dbo.sp_BlitzIndex @DatabaseName = 'Orders', @SchemaName = 'dbo', @TableName = 'SalesOrder', @AI = 1;
<ai_advice>Below is a focused, implementation-ready plan to optimize nonclustered rowstore indexes on [Orders].[dbo].[SalesOrder] based on the current usage and the missing-index suggestions you provided. The plan aims to improve the most common query patterns without over-indexing the table.
What I'm changing and why
- Remove redundant/inefficient index:
- Drop IX_SalesOrder_CustomerType (NONCLUSTERED on CustomerType with includes). Rationale: Its leading column (CustomerType) is not aligned with the most beneficial lookups suggested by SQL Server and the usage statistics show limited activity. It also adds maintenance cost for writes.
- Add targeted indexes aligned with the missing-index suggestions and likely OLTP patterns:
- Create CustomerCode_Status on (CustomerCode, Status) to optimize queries that filter by both CustomerCode and Status. This is the top suggested improvement and should capture a large portion of common lookup patterns for per-customer order filtering.
- Create Status_OrderDate_Includes on (Status, OrderDate) INCLUDE (CustomerCode, CustomerType, OrderTotal) to support queries that filter by Status and OrderDate (often via a range) while returning common columns without lookups.
- Optional: Create OrderDate_Includes on (OrderDate) INCLUDE (CustomerCode, CustomerType, OrderTotal, Status) to support queries filtered by OrderDate alone, if you observe such patterns in production after the first two changes.
- General follow-ups:
- After applying changes, update statistics and monitor index usage to validate benefits and ensure no regression in write-heavy workloads.
- If you still have queries by CustomerType, consider a separate index later only if you see real-world benefit; otherwise the two new indexes above cover the primary missing-index patterns.
Index changes to apply (with undo scripts)
Note: Use ONLINE = ON where supported (Azure SQL DB supports online index operations). If your environment does not support ONLINE, omit ONLINE = ON.
1) Drop existing IX_SalesOrder_CustomerType
- Rationale: align with the workload and avoid maintaining a rarely-used index.
/* Drop existing nonclustered index IX_SalesOrder_CustomerType to reduce maintenance and focus on higher-impact patterns */
DROP INDEX [IX_SalesOrder_CustomerType] ON [Orders].[dbo].[SalesOrder];
/* Undo: Re-create the original index if needed
CREATE NONCLUSTERED INDEX [IX_SalesOrder_CustomerType] ON [Orders].[dbo].[SalesOrder] ([CustomerType])
INCLUDE ([CustomerCode], [OrderDate], [OrderTotal], [Status]);
*/
2) Create CustomerCode_Status
- Rationale: Most beneficial pattern according to missing-index suggestions; supports WHERE CustomerCode = ... AND Status = ...
/* Create composite index to optimize CustomerCode + Status lookups */
CREATE INDEX [CustomerCode_Status] ON [Orders].[dbo].[SalesOrder]
([CustomerCode], [Status])
WITH (ONLINE = ON, FILLFACTOR = 100);
/* Undo:
DROP INDEX [CustomerCode_Status] ON [Orders].[dbo].[SalesOrder];
*/
3) Create Status_OrderDate_Includes
- Rationale: Helps queries that filter by Status and OrderDate (often with a date inequality) and need common output columns without an additional key lookup.
CREATE INDEX [Status_OrderDate_Includes] ON [Orders].[dbo].[SalesOrder]
([Status], [OrderDate])
INCLUDE ([CustomerCode], [CustomerType], [OrderTotal])
WITH (ONLINE = ON, FILLFACTOR = 100);
/* Undo:
DROP INDEX [Status_OrderDate_Includes] ON [Orders].[dbo].[SalesOrder];
*/
4) Optional: Create OrderDate_Includes (only if you observe frequent queries by OrderDate)
- Rationale: Some workloads filter by OrderDate alone and need common columns; this is a broader pattern and adds write cost, so apply only if you see sustained benefit.
CREATE INDEX [OrderDate_Includes] ON [Orders].[dbo].[SalesOrder]
([OrderDate])
INCLUDE ([CustomerCode], [CustomerType], [OrderTotal], [Status])
WITH (ONLINE = ON, FILLFACTOR = 100);
/* Undo:
DROP INDEX [OrderDate_Includes] ON [Orders].[dbo].[SalesOrder];
*/
Additional operational guidance
- After deploying these indexes, run:
- UPDATE STATISTICS [Orders].[dbo].[SalesOrder] WITH FULLSCAN;
- Optionally run sp_updatestats if you're on an older compatibility baseline; in modern SQL Server/Azure SQL DB, UPDATE STATISTICS is preferred.
- Validate with actual workload:
- Check sys.dm_db_index_usage_stats before/after to confirm improved seeks/scans for the targeted queries.
- Monitor write latency and fragmentation on the new indexes. If you see significant fragmentation or impact to inserts/updates, consider adjusting fillfactor or the need for a maintenance window for index rebuilds.
- Consider a phased rollout:
- Start with dropping IX_SalesOrder_CustomerType and creating CustomerCode_Status.
- Observe impact for a maintenance window or a controlled test period before adding Status_OrderDate_Includes.
- If you plan to keep IX_SalesOrder_CustomerType in some scenarios:
- You could turn it into a more selective index by re-evaluating its INCLUDE columns or by dropping it and using the two new focused indexes as the primary lookup paths. In general, leading with a narrow, highly selective key (CustomerType is not highly selective) tends to be less effective than leading with CustomerCode/Status in typical OLTP queries.
Summary
- Removed a misaligned index (IX_SalesOrder_CustomerType) that contributed little to current usage.
- Added two high-potential nonclustered indexes backed by missing-index recommendations:
- CustomerCode_Status on (CustomerCode, Status)
- Status_OrderDate_Includes on (Status, OrderDate) including (CustomerCode, CustomerType, OrderTotal)
- Optional third index (OrderDate_Includes) available if OrderDate-only patterns exist and justify the write overhead.
- Expect better performance for common lookup patterns while keeping write costs in check. Monitor and adjust based on real production telemetry.</ai_advice>
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