In 9.0 (as in earlier versions) a former standby host has to do a full checkpoint before becoming available as an independent database instance in either switchover or failover scenarios.
For most combinations of of bigger than minimal shared buffers and non-memory-speed disks this can take from several seconds to tens of minutes on busy systems. Is the pre-activation checkpoint still required in 9.1 ? The reason I ask is that I'm looking into making planned switchovers and adding partitions more instantaneous. Streaming replication provides replica lag of only millisecond vs. high tens or even hundreds of milliseconds achievable on trigger-based replication systems like Londiste. Where Londiste currently wins, is the ability to become available instantaneously without any checkpoint or other lengthy maintenance operations. -- ------- Hannu Krosing PostgreSQL Infinite Scalability and Performance Consultant PG Admin Book: http://www.2ndQuadrant.com/books/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
