"Carlo Stonebanks" <stonec.register@xxxxxxxxxxxx> writes: > Is there a rule of thumb about when the planner's row estimates are too high? > In particular, when should I be concerned that planner's estimated number of > rows estimated for a nested loop is off? By a factor of 10? 100? 1000? Not really. It's a big enough difference for the planner to make a bad decision or it isn't. But if you pressed me I would say a factor of 10 is bad. A factor of 2 is inevitable in some cases. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
