On Tue, May 29, 2012 at 11:42 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > While I'm looking at this, is the first test involving > effective_cache_size bulletproof either? In particular, is > avgIndexTuplesPerPage clamped to be strictly greater than 1? >
It's based on collected statistics on already inserted tuple sizes. Since tuple sizes are measured after possible toasting, I don't see the way for avgIndexTuplesPerPage to be less than 1. > And for that matter, is either test sane from a units standpoint? > It seems to me that maxIndexTuplesPerPage would have units of > 1/blocks, which is pretty dubious to be comparing to a block count > even disregarding the power function. > In this test we use avgIndexTuplesPerPage as estimate for number of child index pages of one page. I think we can assume it to have blocks unit. ------ With best regards, Alexander Korotkov.
