Database Technologies

PLV8 is a programming language that lets users write stored procedures and triggers in JavaScript and store them in their Postgres database. This allows application programmers to write a lot of their server-side programming in the same language they use to build their web client applications.  Fewer languages to learn usually means fewer mistakes and faster time to completion.  The extensive language support is one of many reasons why Postgres’ use across the world is increasing lately.  The recent addition of document data support with JSON and JSONB data types in PostgreSQL, and in Postgres Plus Advanced Server from EnterpriseDB, is the main reason for the increasing interest in the PL/V8 language extension. Below are the steps you need to compile PLV8 with Postgres Plus Advanced Server 9.3/9.4. To get started, here are the prerequisites: 1. A supported version of PostgreSQL or Postgres Plus Advanced Server, such as versions 9.1 and higher. 2. V8 version 3.14.5 ...

In the series of blogging about new features in 9.3, today, I thought about blogging new functions and improvements coming in PostgreSQL. Lets look whats new in 9.3, in terms of in build functions: 1. New in one array functions for one dimensional array PostgreSQL 9.3, is coming with new functions which can help users to manipulate one dimensional arrays by calling simple functions at the place of crafting their own functions and following some methods to do the modification in it. i. array_remove function This is a new function added in 9.3, which provides ability for removing the elements from array. Function takes two arguments :   a. One dimensional array from which user wants to remove elements   b. element value which user wants to remove . Syntax of this function is given below: ARRAY_REMOVE( , element) Example of array_remove is given below: postgres=# select array_remove(ARRAY['First','Second','Delete','Four'],'D...

This is second post of Postgres Enterprise Manager 2.1 series. Question which people ask, Is Postgres Enterprise Manager tool useful for Companies, which provide services for PostgreSQL? Answer is yes. What about companies, which provide infrastructure support, where they provide server and PostgreSQL database, for them, is this is a good tool for monitoring PostgreSQL? Answer is yes, you can use it. Companies, which are giving Infrastructure support and providing Database As service always want everything to be automated. i.e with provisioning server, server should have installed PostgreSQL and its components plus they want automatic installation of pemagent, which is also acheivable. However, they stumped on Automatic Bidning of PEM Agent with PostgreSQL. For binding PostgreSQL with PEM Agent, Simple Method is using PEM Client. In PEM Client, Add a PostgreSQL in PEM Directory and then user can bind the PEM agent with PostgreSQL Cluster. File -> Add Server -> which will ...

Till PPAS 9.0, UTL_SMTP package has no specific named Exceptions for Transient_error, Invalid_operation and Permanent Error. However, Oracle provide following types of named exceptions for SMTP: 1. INVALID_OPERATION: Raised when an invalid operation is made. In other words, calling API other than write_data(), write_raw_data() or close_data() after open_data() is called, or calling write_data(), write_raw_data() or close_data() without first calling open_data(). 2. TRANSIENT_ERROR: Raised when receiving a reply code in 400 range. 3. PERMANENT_ERROR: Raised when receiving a reply code in 500 range. Oracle users who use SMTP packages, they also use above exceptions extensively to track the SMTP Error/Message and perform some handling on basis of exception. Since, till now PPAS doesn't have these exceptions, therefore people stuck on finding workaround for such exception. To make this easy, I did some research and made following workaround, which user can use in PPAS for...

Slony 2.1 has been released on 19th Oct. 2011. So, I thought to look at some important improvement done in this new release, which can make users life easier. Before discussing about the changes, lets setup slony replication. Following Codes can be use for setting up slony replication. #### Preable Scripts: cluster name=slonytest; NODE 1 ADMIN CONNINFO = 'dbname=postgres host=localhost user=postgres port=5432 password=postgres'; NODE 2 ADMIN CONNINFO = 'dbname=repdb host=localhost user=postgres port=5432 password=postgres'; Adding Node script: ### create_nodes.slonik include ; init cluster (id=1, comment='slonytest node 1'); store node (id=2, comment='slonytest subscriber node 2', event node=1); Storing Path: ### store_paths.slonik include ; STORE PATH (SERVER=1, CLIENT=2, CONNINFO='dbname=postgres host=localhost user=postgres port=5432 password=Empid#042'); STORE PATH (SERVER=2, CLIENT=1, CONNINFO='dbname=repdb host=localhost us...

In my Blog on get_number_of_segments, I had used the simple query to find the number of segments. Since, from PostgreSQL 9.0, system admin function pg_relation_filepath can be use to find the location of relfilenode, therefore I thought to reduce the code of get_number_function and use the pg_relation_filepath function. Following is a modified plperl function get_number_of_segments(text) using system admin function pg_relation_filepath(relation reglcass): CREATE OR REPLACE FUNCTION get_number_of_segments(text) returns table(tablename text, segments int) as $$ my $sql = spi_prepare("select 'ls -1 '||pg_relation_filepath(\$1)||'.*' as cmd",'TEXT'); my $q = spi_query_prepared($sql,$_[0]); my $rv = spi_fetchrow($q); my $cmd = $rv->{rows}[0]; my $command = $cmd -> {location}; open(CMD, "$command |"); $count = ; close(CMD); @count=split(/[\n\r]+/,$count); return_next...