Кэш Postgresql (память) производительность +, как нагреть кэш

Regarding your first point, the contrib module "pg_buffercache" allows you to inspect the contents of the buffer cache. I like to define this:

create or replace view util.buffercache_hogs as
select case
       when pg_buffercache.reldatabase = 0
            then '- global'
       when pg_buffercache.reldatabase <> (select pg_database.oid from pg_database where pg_database.datname = current_database())
            then '- database ' || quote_literal(pg_database.datname)
       when pg_namespace.nspname = 'pg_catalog'
            then '- system catalogues'
       when pg_class.oid is null and pg_buffercache.relfilenode > 0
            then '- unknown file ' || pg_buffercache.relfilenode
       when pg_namespace.nspname = 'pg_toast' and pg_class.relname ~ '^pg_toast_[0-9]+$'
            then (substring(pg_class.relname, 10)::oid)::regclass || ' TOAST'::text
       when pg_namespace.nspname = 'pg_toast' and pg_class.relname ~ '^pg_toast_[0-9]+_index$'
            then ((rtrim(substring(pg_class.relname, 10), '_index'))::oid)::regclass || ' TOAST index'
       else pg_class.oid::regclass::text
       end as key,
       count(*) as buffers, sum(case when pg_buffercache.isdirty then 1 else 0 end) as dirty_buffers,
       round(count(*) / (SELECT pg_settings.setting FROM pg_settings WHERE pg_settings.name = 'shared_buffers')::numeric, 4) as hog_factor
from pg_buffercache
     left join pg_database on pg_database.oid = pg_buffercache.reldatabase
     left join pg_class on pg_class.relfilenode = pg_buffercache.relfilenode
     left join pg_namespace on pg_namespace.oid = pg_class.relnamespace
group by 1
order by 2 desc;

Additionally, the "pageinspect" contrib module allows you to access a specific page from a relation, so I suppose you could simply loop through all the pages in a relation grabbing them?

select count(get_raw_page('information_schema.sql_features', n))
from generate_series(0,
        (select relpages-1 from pg_class where relname = 'sql_features')) n;

This will load all of information_schema.sql_features into the cache.

Ad. 1 - Совершенно без идей.

Ad. 2 - почему бы вам просто не выбрать случайным образом несколько важных для вас запросов и не запустить их на холодном сервере? чем больше запросов вы запустите, тем лучше будет процесс разминки.

2) I usually solve this by having a log of queries from a live system and replaying them. This warms up the typical parts of the data and not the parts that aren't as frequently used (which would otherwise waste RAM).