"Mark Dexter" <[EMAIL PROTECTED]> writes: > 1. Would it be difficult to add an option to ANALYZE to force it to > pretend that there are a minimum number of rows (e.g., ANALYZE MINIMUM > 1000 or something)? This would appear to be a simple-minded way to > solve the problem without any concerns about backward compatibility.
This strikes me as useless, not to mention not backward-compatible at all. Where is ANALYZE supposed to come up with the data to fill pg_statistic? Shall we add the same kluge option to VACUUM and CREATE INDEX? > 2. Why does a newly CREATE'd table behave differently than an empty > table after ANALYZE? Does it make sense that it should? This is a long-standing hack, which I am proposing undoing; see http://archives.postgresql.org/pgsql-patches/2004-11/msg00339.php and in particular read the comments that the patch deletes. > 3. Has anyone ever tested whether there is a measurable performance > gained after doing ANALYZE on empty or nearly empty tables? As long as the table *stays* empty or nearly so, the knowledge that it is small is good for the planner to have. The problem we are dealing with here boils down to the fact that a table can grow substantially without the planner being aware of the fact. So IMHO the correct solution is to attack that problem head-on, not to invent weird options to make ANALYZE lie about what it found. CREATE TABLE shouldn't be lying either, but at one time that seemed like a good quick-hack workaround ... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly