Tom, > Partly. The numbers suggest that in ANALYZE's default sample of 3000 > rows, it's only finding about a dozen non-null tgroup_ids (yielding the > 0.996 null_frac value); and that in one case all dozen are different and > in the other case there are two duplicates. It would help if you > boosted the stats target for this column by a factor of 10. (You can > do that in 7.2, btw --- IIRC the only problem is that a pg_dump won't > show that you did so.)
Hmmm. No dice. I raised the selectivity to 1000, which increased n_distinct to 108, which is pretty close to accurate. However, the planner still insists on using a seq scan on case_clients unless I drop random_page_cost to 1.5 (which is up from 1.2 but still somewhat unreasonable). > But the other part of the problem is that in 7.2, the join selectivity > estimator is way off when you are joining a unique column (like the pkey > on the other side) to a column with a very large fraction of nulls. > We only discovered this recently; it's fixed as of 7.3.3: OK, I'll talk to the client about upgrading. -- -Josh Berkus ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete information technology [EMAIL PROTECTED] and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])