On Mon, Oct 31, 2016 at 6:56 AM, Emre Hasegeli <e...@hasegeli.com> wrote: > The BRIN Bitmap Index Scan has the same problem. I have seen people > confused by this. I think N/A would clearly improve the situation.
I agree. Or perhaps better still, leave rows=%.0f out altogether when we don't have a meaningful value to report. If it were OK to use some unimportant-looking value as a proxy for "undefined", the SQL standard wouldn't include nulls. I don't like Tom's proposal of trying to fake up a value here when EXPLAIN ANALYZE is in use. Reporting "exact" and "lossy" values for BitmapAnd would be a fine enhancement, but artificially trying to flatten that back into a row count is going to be confusing, not helpful. (Just last week I saw a case where the fact that many pages were being lossified caused a performance problem ... so treating lossy pages as if they don't exist would have led to a lot of head-scratching, because under Tom's proposal the row count would have been way off.) -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
