What does SQL Server do between returning my first record and returning my last record?

Question

Let's say I have a query that returns 10,000 records. When the first record returned, what can I assume about the status of my request?

• Is it ready and just returns records from the server to my SSMS instance?
• Is the request running on the server?
• What causes 10,000 records to slowly return for one request and almost instantly for another?

Answer 1

There is potentially some combination of server-side progressive processing, network data transfer, and client rendering.

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