> Would be nice to sort out the features of the two Postgres extentions > pgfincore (https://github.com/klando/pgfincore ) and pg_prewarm: what > do they have in common, what is complementary?
pg_prewarm use postgresql functions (buffer manager) to warm data (different kind of 'warm', see pg_prewarm code). Relations are warmed block by block, for a range of block. pgfincore does not use the postgresql buffer manager, it uses the posix calls. It can proceed per block or full relation. Both need POSIX_FADVISE compatible system to be efficient. The main difference between pgfincore and pg_prewarm about full relation warm is that pgfincore will make very few system calls when pg_prewarm will do much more. The current implementation of pgfincore allows to make a snapshot and restore via pgfincore or via pg_prewarm (just need some SQL-fu for the later). > > I would be happy to test both. But when reading the current > documentation I'm missing installation requirements (PG version, > replication? memory/hardware requirements), specifics of Linux (and > Windows if supported), and some config. hints (e.g. > relationships/dependencies of OS cache and PG cache an > postgresql.conf). pgfincore works with all postgresql stable releases. Probably idem for pg_prewarm. in both case, make && make install, then some SQL file to load for <=9.0. With 9.1, once you've build and install, just CREATE EXTENSION pg_fincore; (probably the same with pg_prewarm) > > -Stefan > > 2012/3/11 Cédric Villemain <ced...@2ndquadrant.com>: > > Le vendredi 9 mars 2012 16:50:05, Robert Haas a écrit : > >> On Fri, Mar 9, 2012 at 10:33 AM, Dimitri Fontaine > >> > >> <dimi...@2ndquadrant.fr> wrote: > >> > So that's complementary with pgfincore, ok. I still wish we could > >> > maintain the RAM content HOT on the standby in the same way we are > >> > able to maintain its data set on disk, though. > >> > >> That's an interesting idea. It seems tricky, though. > > > > it is the purpose of the latest pgfincore version. > > I use a varbit as output of introspection on master, then you are able to > > store in a table, stream to slaves, then replay localy. > > > > -- > > Cédric Villemain +33 (0)6 20 30 22 52 > > http://2ndQuadrant.fr/ > > PostgreSQL: Support 24x7 - Développement, Expertise et Formation > > > > -- > > Sent via pgsql-hackers mailing list (firstname.lastname@example.org) > > To make changes to your subscription: > > http://www.postgresql.org/mailpref/pgsql-hackers -- Cédric Villemain +33 (0)6 20 30 22 52 http://2ndQuadrant.fr/ PostgreSQL: Support 24x7 - Développement, Expertise et Formation