2016-08-18 16:56 GMT+03:00 Tom Lane <t...@sss.pgh.pa.us>: > In that case you've got random_page_cost too far down. Values less than > the default of 4 are generally only appropriate if the bulk of your > database stays in RAM. >
Oh, that's interesting. I was under impression, that r_p_c reflects IO speed, like — make it smaller for SSDs. To make this query prefer BitmapScan, I need to bump r_p_c to 5.8. And 6.0 makes it switch to SeqScan. Does it means, that for huge DB (this one is ~1.5TB) it is better to increase r_p_c? Still, this effect shows only for partial indexes, i.e. if I disable ` idx_loan_agreemnets_loan_id_cond_is_current_true`, than planner will not use any other and goes straight to SeqScan. Does it means, that amount of table-related IO is not accounted for when planning scan over partial index? -- Victor Y. Yegorov
