Database Technologies

In series of blogging about new features coming in PostgreSQL 9.3, I thought to blog about the server side language improvements in PostgreSQL. Lets see whats coming in server side language. As PostgreSQL user, you know, PostgreSQL supports multiple server side language. In 9.3, there are some interesting features are coming. Lets look at the new improvements about to come. 1. SPI access to number of rows processed by COPY command. This is more like new feature which is introduced in 9.3. Before 9.3, this feature was missing. i.e if user uses COPY command inside the plperl/plpython functions, then there was no way inside the procedure to trace the number of rows processed by COPY. However in 9.3, this limitation is no more exists with procedural language. There are many languages supported in PostgreSQL, However I chose to test this with mostly used language plperl and plpython. Below are some snapshot pre-9.3 and in 9.3. Lets check with plperl. Following is a plperl function w

Good News Postgres Plus Advanced Server Beta Version is now availabale, which has all the new feature of PostgreSQL 9.2, and it also has new features which are specific to Advanced Server. I will cover/explain New features of PostgreSQL 9.2 later as per release Notes. However, the following link covers major features of PostgreSQL 9.2 and can be taken as reference. http://wiki.postgresql.org/wiki/What's_new_in_PostgreSQL_9.2 In this Blog, I am going to cover only specific features of Advanced Server 9.2 Core. Which are: 1. INSERT APPEN HINT in PPAS 9.2 PPAS 9.2, now supports INSERT append hint. This is a very interesting feature and it is very useful for users who frequently delete records in Bulk and do bulk of INSERTs. This hint can provide some benefits in INSERTs. This hint makes PPAS not use Free Space Map and Append the rows at the end of relation(table). Its usage is given below: INSERT /*+append*/ INTO tab21115 VALUES(1,'abc',sysdate); 2. Procedure Called l

This has been asked me many times. Many users has asked me how they can create READ-ONLY user, READ-ONLY Database or How they can create backup user which can be use only for backup (no modification) Well answer is in parameter called default_transaction_read_only. If you want to make a user READ-ONLY, then you can follow steps given below: 1. CREATE normal user. 2. Use ALTER USER command to set this parameter for this user as given below: ALTER USER set default_transaction_read_only = on; 3. GRANT SELECT to this user for tables/object using GRANT. And you are good to go. Below is snapshot: postgres=# create user readonly password 'test'; CREATE ROLE postgres=# alter user readonly set default_transaction_read_only = on; ALTER ROLE postgres=# GRANT select on employees to readonly; GRANT edbs-MacBook-Pro:data postgres$ psql -U readonly -W Password for user readonly: psql (9.1.1) Type "help" for help. postgres=> select * from employees ; employee_name | e

Since, PostgreSQL 9.1 has already been released and there are lot of new features added in it, so, I thought to blog about each features. Today, I am discussing about Synchronous and Asynchronous Replication supported in PostgreSQL 9.1. For Asynchronous Replication, user can use following method: 1. Change Following Parameters in postgresql.conf file of Primary Database: archive_command = cp -i %p /Users/postgres/archive/%f archive_mode = on max_wal_senders = 3 # Maximum 'wal_senders', processes responsible for managing a connection with a standby server wal_keep_segments = # How many WAL segments (=files) should be kept on the primary, whatever may happen (you won't have to copy them manually on the standby if the standby gets too far behind) wal_level = hot_standby 2. Make Following changes in pg_hba.conf host replication postgres [Ipv4 address of Standby Server]/32 trust host replication postgres [Ipv4 address of Master Server]/32 tr

Depsez has Started a New project called Curo, which is currently made for Unix/Linux and is in initial phase. So, I thought to look at how it works and how normal user, who knows using psql, can benefit from it. Before Installing Curo, user has to make sure, he has postgreSQL client: psql and following package installed on his Linux/Unix System: 1. Bash 2. dialog If you have above required packages on your machine, then you can move for Curo installation. Curo Installation is very simple. Following are the steps which can be use to install Curo on Unix/Linux System: 1. Download the Curo from Following link: https://github.com/omniti-labs/curo Above link will give you file similar to given below: omniti-labs-curo-48a4f31.tar.gz 2. Untar the file using following command: tar -xvf omniti-labs-curo-48a4f31.tar.gz 3. Copy omniti-labs-curo-48a4f31 to users home directory as given below: cp omniti-labs-curo-48a4f31 ~/.curo 4. Now configure .inputrc and .editrc file as given