Finding Eager Index Spools in the Plan Cache
Somewhere in your plan cache right now, there is probably a query quietly building an index every single time it runs. Not once. Every execution. It builds the index, uses it, and throws it away,…
What ROW and PAGE Compression Do to the Record
This post is part of the series. The contents page lists every part in order. Data compression is one of the few storage features you can turn on with a single clause and measure the…
A Tour of SQL Server Page Types: Data, GAM, SGAM, PFS, IAM
Most of this storage series has been spent inside data pages, pulling rows apart byte by byte. But a data file is not only data pages. Scattered through it, at fixed and predictable spots, are…
Forwarded Records: What an UPDATE Can Do to a Heap
This post is part of the series. The contents page lists every part in order. A heap, a table with no clustered index, has a failure mode that clustered tables do not: an UPDATE that…
Row-Overflow and LOB: When a Row Leaves the Page
This post is part of the series. The contents page lists every part in order. A data page is 8 KB, and a single row is capped at 8,060 bytes of in-row data.[1] So what…
How SQL Server Packs BIT Columns Into a Single Byte
This post is part of the series. The contents page lists every part in order. A common worry about bit columns is that a table full of yes/no flags will waste a byte on every…