Re: How is random_page_cost=4 ok? - Mailing list pgsql-hackers

From Ron Mayer
Subject Re: How is random_page_cost=4 ok?
Date
Msg-id 48EFCAAB.7020702@cheapcomplexdevices.com
Whole thread Raw
In response to Re: How is random_page_cost=4 ok?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> In particular, if the OS lays out successive file pages in a way that
> provides zero latency between logically adjacent blocks, I'd bet a good
> bit that a Postgres seqscan would miss the read timing every time, and
> degrade to handling about one block per disk rotation.

Unless the OS does some readahead when it sees something like a seq scan?



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