CS 491/591 Linux Administration and Security PostgreSQL (database) Installation Installation Configuration Configuration Basic Security Basic Security Gulsen Gulsen

What is PostgreSQL? PostgreSQL is an Object-Relational Database Management System (ORDBMS) that has been developed in various forms since It’s an open source project. It means that you can obtain the source code, use the program, and modify it freely without the confines of proprietary software.

PostgreSQL provides a wealth of features that are usually only found in commercial databases such as Oracle. The following is a brief listing of some of these core features: It supports user-defined operators, functions, access methods, and data types. It supports user-defined operators, functions, access methods, and data types. It supports the core SQL99 specification. It supports the core SQL99 specification. It supports referential integrity, which is used to insure the validity of a database's data. It supports referential integrity, which is used to insure the validity of a database's data. The flexibility of the PostgreSQL API has allowed vendors to provide development support easily for the PostgreSQL RDBMS. These interfaces include Object Pascal, Python, Perl, PHP, ODBC, Java/JDBC, Ruby, TCL, C/C++, and Pike. The flexibility of the PostgreSQL API has allowed vendors to provide development support easily for the PostgreSQL RDBMS. These interfaces include Object Pascal, Python, Perl, PHP, ODBC, Java/JDBC, Ruby, TCL, C/C++, and Pike.

Conti…. It uses a process-per-user client/server architecture. It uses a process-per-user client/server architecture. The PostgreSQL feature known as Write Ahead Logging increases the reliability of the database by logging changes before they are written to the database. This ensures that, in the unlikely occurrence of a database crash, there will be a record of transactions from which to restore. This can be greatly beneficial in the event of a crash, as any changes that were not written to the database can be recovered by using the data that was previously logged. Once the system is restored, a user can then continue to work from the point that they were at before the crash occurred. The PostgreSQL feature known as Write Ahead Logging increases the reliability of the database by logging changes before they are written to the database. This ensures that, in the unlikely occurrence of a database crash, there will be a record of transactions from which to restore. This can be greatly beneficial in the event of a crash, as any changes that were not written to the database can be recovered by using the data that was previously logged. Once the system is restored, a user can then continue to work from the point that they were at before the crash occurred.

PostgreSQL Installation First, you can check if you have PostgreSQL database server already installed. Type the following command in your terminal. rpm -qa | grep postgresql If you get postgresql x or something alike when the command is executed, it means that you already have PostgreSQL database software installed.

Conti… If you don't have PostgreSQL installed, you will need to download PostgreSQL from binary RPM distribution from or its mirror sites. You can download the latest version of PostgreSQL from the following address: ftp://ftp3.us.postgresql.org/pub/postgr esql/binary/v8.0.3/linux/rpms/

Conti… You will need to install postgresql-libs first. If you want to run server, install postgresql - server and postgresql -rpms. The other packages are for developing applications, docs, tcl, perl, etc support. Run the following commands to install: rpm -ivh postgresql-libs PGDG.i686.rpm rpm -ivh postgresql-server PGDG.i686.rpm rpm -ivh postgresql PGDG.i686.rpm

PostgreSQL Configuration First check whether PostgreSQL is running: "/etc/rc.d/init.d/postgresql status” you should get some information back saying that is it running like this "postmaster (pid ) is running...” First check whether PostgreSQL is running: "/etc/rc.d/init.d/postgresql status” you should get some information back saying that is it running like this "postmaster (pid ) is running...” The user "postgres" should have already been configured by the installation of the RPMs. A password will be missing. So, we need to assign a password for user postgres: “passwd postgres” The user "postgres" should have already been configured by the installation of the RPMs. A password will be missing. So, we need to assign a password for user postgres: “passwd postgres”

Conti… Login as a user postgres: “su –postgres” Login as a user postgres: “su –postgres” This will execute the profile: “/var/lib/pgsql/.bash_profile ” This will execute the profile: “/var/lib/pgsql/.bash_profile ” To initialize PostgreSQL database server: To initialize PostgreSQL database server: “initdb --pgdata=/var/lib/pgsql/data” “initdb --pgdata=/var/lib/pgsql/data” This creates a bunch of directories, a template directory and sets up the postgres configuration in the user directory “/var/lib/pgsql/” This creates a bunch of directories, a template directory and sets up the postgres configuration in the user directory “/var/lib/pgsql/” To start the database server. As root: To start the database server. As root: “service postgresql start” or “/etc/rc.d/init.d/postgresql start” “service postgresql start” or “/etc/rc.d/init.d/postgresql start”

Conti… To create a database: “createdb magic” To create a database: “createdb magic” To connect to database: “psql magic” To connect to database: “psql magic” Now, you will be at the PostgreSQL command line prompt: Now, you will be at the PostgreSQL command line prompt: psql magic psql magic Welcome to psql, the PostgreSQL interactive terminal. Welcome to psql, the PostgreSQL interactive terminal. Type: \copyright for distribution terms Type: \copyright for distribution terms \h for help with SQL commands \h for help with SQL commands \? for help on internal slash commands \? for help on internal slash commands \g or terminate with semicolon to execute query \g or terminate with semicolon to execute query \q to quit \q to quit magic=# magic=#

Basic Network and Security Configuration To allow PostgreSQL to accept TCP/IP connections from the JDBC driver: To allow PostgreSQL to accept TCP/IP connections from the JDBC driver: “/var/lib/pgsql/data/postgresql.conf” “/var/lib/pgsql/data/postgresql.conf” change “tcpip_socket=false” to “tcpip_socket=true” change “tcpip_socket=false” to “tcpip_socket=true” PostgreSQL allows anyone from the local machine to connect to the databases PostgreSQL allows anyone from the local machine to connect to the databases without a password challenge. So, if other users are using your computer without a password challenge. So, if other users are using your computer

Conti… “/var/lib/pgsql/data/pg_hba.conf ” go to the end of the file, and change the authorization end of the file, and change the authorization checks from “trust” to “password” checks from “trust” to “password” Start server again: Start server again: “service postgresql start” “service postgresql start”