Hi Tom,
Tom Raney wrote:
> We used spool functions from the BTree code to sort the index
> tuples. Sorting is done on the hash value of the tuples. The hash
> value depends on the number of primary bucket pages (henceforth
> just bucket pages) that will be required to fit all the index
> tuples. So, before sorting, the base relation is scanned to get
> the total number of tuples.
Just wondering, wouldn't it be enough to obtain a tuple count estimate
by using reltuples / relpages * RelationGetNumberOfBlocks, like the
planner does?
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.