Database Technologies

Security has always been a great concern of Enterprises. Especially, if you have crucial information stored in the database, you would always prefer to have high security around it. Over the years, technologies have evolved and provided better solutions around it. If you have very sensitive information, people try to keep this information encrypted so, that in case, somebody gets access of the system, then they cannot view this information, if they are not authorized. For managing sensitive information, Enterprises use multiple methods: 1. Encrypting specific information. If you are PPAS users, you would like to use DBMS_CRYPTO package which provides a way of encrypting sensitive information in databases. For more information, please refer following link: http://www.enterprisedb.com/docs/en/9.4/oracompat/Database_Compatibility_for_Oracle_Developers_Guide.1.178.html# For PostgreSQL, users can use pgcrypto module. 2. Transparent Data Encryption (TDE) is anot...

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...

PostgreSQL has some useful functions which can be use to know about the privilege of a user on a particular Database object. Those functions is available in following link: http://www.postgresql.org/docs/9.1/static/functions-info.html Functions has_*_privilege in PostgreSQL/PPAS is good to know about privilege a user has on one database objects and these function returns boolean value true or false. Since, DBAs/Users are interested in listing objects and privileges of a Database User and currently PostgreSQL doesn't have a view, which DBA can use to list users privileges on objects for a particular database. Therefore, I thought about making some functions, which can be used to list users privileges, based on what is available in PostgreSQL/PPAS 9.1. These are basic functions and can be expanded, as per need, to show more privileges like WITH GRANT OPTION. Following are functions which can use to get the privileges of a particular user: 1. Function for table privileges: C...

PostgreSQL has pg_stat_activity view which can be use to get the session details. This view gives following information: 1. datid: database OID 2. datname: database name 3. procpid: process ID 4. usesysid: user OID 5. usename: user name 6. application_name: application name 7. client_addr: client's address 8. client_hostname: host name (if available) 9. client_port: Clients port number 10. backend_start: time at which the server process started 11. xact_start: time at which current transaction started 12: query_start: time at which current query began execution started 13: waiting: process's waiting status 14. current_query: text of the current query. Above is good for monitoring sessions in postgresql. However, suppose user wants to know about percentage of CPU & Memory used by a particular session/user, then he can get this information by using plperlu function. To Create the pleperlu function, user needs to have plperlu language installed in DB. For creating the p...

This is also one type of thing in which people are very interested. How to create probes other than PEM inbuilt probe? And how to create alert based on probe? Well answer is simple. Understand what probe is in PEM and then understand PEM Data detail. Probe in PEM requires following: 1. SQL Code which can be use to gathering data by pemagent. 2. Table in pemdata schema, which will be use for storing Current status/data of SQL. 3. History table (specially in pemhistory schema) where all history data will reside. Suppose user wants to monitor the Slony Replication using PEM (since, PEM doesn't have slony replication moniotring), so user can do following: 1. SQL Code which can be use for slony replication monitoring. We know that slony replication monitoring can be done using view sl_status of slony. So, user can create a SQL Code as given below for replication. select '_test_slony' as schema_name, st_origin,st_received, st_lag_num_events , st_lag_time from _test_slony...

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 ...