Since I don't recall any ideas ever having been thrown out on how to do this...
ISTM that we could gain additional insight on how many rows would likely result from a join be comparing the "shape" of the histogram for the joining columns. For example, if the histogram arrays were exactly identical, we're essentially stuck looking at the ratio of reltuples between the two tables. (AFAIK that's the only estimate we make today) If one histogram ended at a value smaller than the start of the other histogram, we would estimate that no rows would result from an equal join. Am I right about how our estimates work right now? Where can I look in the code? Has anyone looked down this path in the past? -- Jim Nasby [EMAIL PROTECTED] EnterpriseDB http://enterprisedb.com 512.569.9461 (cell) ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
