Hello

First, the proposed changes in this email are to be used at least for

PostgreSQL extensions, maybe for core.

Purpose is to offer better monitoring/tracking of the hot/cold areas (and

read/write paterns) in the tables and indexes, in PostgreSQL those are by default

written in segments of 1GB.

There are some possible usecase already:

* planning of hardware upgrade

* easier configuration setup (both PostgreSQL and linux)

* provide more informations to the planner/executor of PostgreSQL

My ideas so far are to

* improve mincore() in linux and add it information like in freeBSD (at

least adding 'mincore_modified' to track clean vs dirty pages).

* adding fincore() to make the information easier to grab from PostgreSQL (no

mmap)

* maybe some access to those stats in /proc/

It makes years that libprefetch, mincore() and fincore() are discussed on linux

mailling lists. And they got a good feedback... So I hope it is ok to keep on

those and provide updated patches.

Johannes, I add you in CC because you're the last one who proposed something. Should I update your patch ?

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Cédric Villemain +33 (0)6 20 30 22 52

http://2ndQuadrant.fr/

PostgreSQL: Support 24x7 - Développement, Expertise et Formation