Amit Gupta amit.pc.gu...@gmail.com writes:
Moreover it only models a single index scan. It assumes nothing is cached
prior to the index scan which is very much not true if we're repeatedly
scanning similar ranges of keys.
It's reasonable to assume that nothing is cached for estimating the
While trying to figure out an appropriate cost expression function for
Thick indexes, i learned that we are using Mackert and Lohman formula
(described in their paper Index Scans Using a Finite LRU Buffer: A
Validated I/O Model, ACM Transactions on Database Systems).
The paper's result is as
Amit Gupta amit.pc.gu...@gmail.com writes:
Upon taking a cursory look at the cost functions of other operators, I
realized that available memory (effective_cache_size) is not
considered for estimating the costs of hash/sort/NLjoin/etc. Why is
that the case?
The relevant number for those is
Amit Gupta amit.pc.gu...@gmail.com writes:
While trying to figure out an appropriate cost expression function for
Thick indexes, i learned that we are using Mackert and Lohman formula
(described in their paper Index Scans Using a Finite LRU Buffer: A
Validated I/O Model, ACM Transactions on
