Talk about pgcenter utility - what is it, how to use it, how to find problems related with postgresql performance

 

PgCenter It's well known that PostgreSQL has rich activity statistics that allow a better understanding of its internal processes. Top-like interface for viewing stats. System resource utilization (cpu, memory, storage, networking). PostgreSQL general utilization (connections, autovacuum, qps) Common admin tasks.

Configure Streaming Replication in PostgreSQL

By default, Streaming replication is asynchronous meaning, once a transaction is committed on the primary, there is a slight delay when that same transaction is committed, and written on the replica. There is potential for data loss with this type of configuration.

Install PgBadger in Linux and set configurations

Untar the file and make a Perl file

#tar -zvxf pgbadger-4.1.tar.gz 
#cd pgbadger-4.1
#perl Makefile.PL
WARNING: META_MERGE is not a known parameter.
Checking if your kit is complete...
Looks good
'META_MERGE' is not a known MakeMaker parameter name.
Writing Makefile for pgBadger

FATAL: requested timeline 3 is not a child of this server's history

When we perform a switch-over, the replica fails to start with below errors.

Switchover - master server and warm standby (with streaming replication) in PostgreSQL

Switch-over of a master database to replica is pretty easy. Lets see how we do it.. 

 I have 2 servers : 5522(data_replica2) and 5432(data), and at this time, 5522 is the master server and 5432 is a warm standby with streaming replication. 

pg_dump: aborting because of server version mismatch

Initiating backup using pg_dump keeps on failing with error as below :

pg_dump: [archiver (db)] query was: LOCK TABLE

While performing backup using pg_dump with database user fails with error as below :

pg_restore with -C option fails to create database. FATAL: database "nexaprod" does not exist

When you use pg_restore you have various options available, for example : 

-c to drop database objects before recreating them,

-C to create a database before restoring into it,

initialise multiple postgres instance on same RHEL server

It is pretty easy to install multiple instances of PostgreSQL servers on same server and have its benefits.

Who uses Postgresql

A good read Who uses Postgresql 

Postgres | Query to identify the lag among the Primary and Replica

How to stop starting of clusters while starting up services

Infra activities such as upgrade, OS patching or Sevrer maintaince activity may require disabling the auto startup of any specific cluster or if you want  NOT auto start on a call such as sudo service postgresql start

pgtune | installation and usage

pgtune helps expands the database server to be as powerful as the hardware it's being deployed on , by taking an existing postgresql.conf file as an input, making changes to it based on the amount of RAM in your server and suggested workload, and output a new file.

pg_basebackup: could not connect to server: FATAL: number of requested standby connections exceeds

-bash-4.1$ pg_basebackup -h oracleasm1.localdomain -D /u01/PG_Adventure
pg_basebackup: could not connect to server: FATAL:  number of requested standby connections exceeds … 

pg_basebackup : could not connect to server: FATAL: no pg_hba.conf entry for replication connection

pg_basebackup: could not connect to server: FATAL:  no pg_hba.conf entry for replication connection from host "127.0.0.1", user "postgres", SSL off