This area of the website contains a collection of long, in-depth articles. Each of them can be read online or downloaded in PDF format.
Anatomy of a spool
In this article, I take a look under the cover of the spool operators to investigate the exact structure used by the worktable that stores the spooled data. Microsoft provides very little documentation on this, and the little there is is actually incorrect! All spool types (Table Spool, Index Spool, and the undocumented stack spool) organize their worktable as a clustered index. The spool types differ in what they use as the key for that clustered index, and in when rows are deleted.
The findings are described on the first page. The rest of the article details the methods I used for this investigation.