Hi,

When analyzing the plan of a query I often find myself questioning whether an additional index may be sensible, or if it is sensible that a SeqScan is used if an index is available.

The current EXPLAIN ANALYZE only shows the number of tuples matching the qualifier of an SeqScan Node - for analyzing the above situation it is at least equally interesting how many tuples were read and discarded.

Therefore I produced a patch which adds a 'discarded=%f' part to the analyze output. As this is only a RFD the implementation is a bit hackish at the moment - the discarded counter is increased in execScan directly instead of a helper routine in instrument.c. Also the discarded count is displayed in other node types as well - for some there might be a sensible semantic meaning to it...

Good idea - Bad idea?

Greetings,

Andres

--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to