Question: What Happens If the Clustered Index is Disabled?
Answer: If you disable the clustered index, you can’t retrieve data from the table.
Question: How to Force Index on a SQL Server Query?
Answer: I personally do not like to force an index on any query. Let us learn together.
These index design rules came from a client’s list of ten index don’ts, and readers argued with several of them. This post turns the checkable rules into read-only queries on a demo database, and it measures what each rule really costs. The rest are warnings, not laws, and the post says which is which.
The question was do heaps are very bad and always force a table scan? Let us learn about RID Lookup, Heaps and table scan.
Compare RID lookups on heaps with clustered key lookups, inspect forwarded records, and test covering indexes with actual plans and reads.
NEWID vs NEWSEQUENTIALID decides whether new uniqueidentifier keys land at random in your clustered index or in order at the end. This post loads 20,000 rows with each default, measures pages, fullness and fragmentation, and shows the limits of NEWSEQUENTIALID. It also answers what happens when you switch the default on a table that already has rows.
To check index fragmentation with row count, read sys.dm_db_index_physical_stats in SAMPLED mode and keep the page count and row count next to each percentage. This post builds a demo with three tables, lists every index, filters out the tiny ones, loops over every online database, and rebuilds the one index that matters.