Switchover/Switchback in Slony-I while upgrading PostgreSQL major versions 8.4.x/9.3.x

Every new release of PostgreSQL comes with a packed of exciting features. To benefit new features, database server should be upgraded. Choosing traditional upgrade paths like pg_dump/pg_restore or pg_upgrade requires a significant downtime of application. Today, if you are looking for minimum downtime upgrade path among major PostgreSQL versions with perfect rollback plan, then it…

How to replicate only INSERTs not DELETEs/UPDATEs on Slony Slave Node ?

In the first place, we need to know about why such requirement needed. IMO, its absolutely a business necessity to maintain some kind of historical data on the target database(Slave Node). Especially, out of multiple slave nodes one of the slave node to retain the very first form of the data when it initially written…

Utilising caching contrib’s pg_prewarm and pg_hibernator in PostgreSQL 9.4.

Numerous DBA’s (counting me), put questions all the time to PostgreSQL hackers/developers/architects on mailing list: Q1. Does PG has the ability to cache/warm a relation ? Q2. Is it possible to return to prior state of cache where it was left before shutting down the database server because of maintenance ? In earlier releases of…

Few areas of improvements in PostgreSQL 9.4

With the beta release of PostgreSQL 9.4, DBA’s have been given some cool features like pg_prewarm, JSONB, ALTER SYSTEM, Replication Slots and many more. Out of numerous architectural level features presented in this version, likewise there are other few minor enhancements those I have attempted to cover in this blog. pg_stat_activity view included two new…

“WARNING: Mismatch found between sl_table and pg_class.” in Slony-I

WARNING: Mismatch found between sl_table and pg_class. Slonik command REPAIR CONFIG may be useful to rectify this.2014-04-26 07:32:54 PDT FATAL slon_node_health_check() returned false – fatal health problem!REPAIR CONFIG may be helpful to rectify this problem You see this WARNING message in logs and immediate stop of replication, if Slony has observed a mismatch of pg_class.oid…