Beyond Linux® From Scratch (systemd Edition) - Version 10.0

Chapter 22. Databases

PostgreSQL-12.4

Introduction to PostgreSQL

PostgreSQL is an advanced object-relational database management system (ORDBMS), derived from the Berkeley Postgres database management system.

This package is known to build and work properly using an LFS-10.0 platform.

Package Information

PostgreSQL Dependencies

Optional

Python-2.7.18, libxml2-2.9.10, libxslt-1.1.34, OpenLDAP-2.4.51, Linux-PAM-1.4.0, MIT Kerberos V5-1.18.2 and Bonjour

Optional (To Regenerate Documentation)

fop-2.5, docbook-4.5-dtd, docbook-dsssl-1.79, DocBook-utils-0.6.14, OpenJade-1.3.2, and SGMLSpm-1.1

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/postgresql

Installation of PostgreSQL

For enhanced security, it is better to have a dedicated group and user for running the PostgreSQL server. First, issue as the root user: 

groupadd -g 41 postgres &&
useradd -c "PostgreSQL Server" -g postgres -d /srv/pgsql/data \
        -u 41 postgres
[Note]

Note

There are several configuration items that add additional functionality with optional packages to PostgreSQL. Use ./configure --help to see a list.

Install PostgreSQL with the following commands: 

sed -i '/DEFAULT_PGSOCKET_DIR/s@/tmp@/run/postgresql@' src/include/pg_config_manual.h &&

./configure --prefix=/usr          \
            --enable-thread-safety \
            --docdir=/usr/share/doc/postgresql-12.4 &&
make

There are a number of programs in the contrib/ directory. If you are going to run this installation as a server and wish to build some of them, enter make -C contrib or make -C contrib/<SUBDIR-NAME> for each subdirectory.

Tests must be run as an unprivileged user because they need to start a temporary server and this is prevented as the root user. For the same reason, you need to stop all PostgreSQL servers if any are running. If a previous version of PostgreSQL is installed, it may be necessary to use --disable-rpath with configure to avoid failures, but installing the binaries created using this switch is not recommended. To test the results, issue: make check.

Now, as the root user: 

make install      &&
make install-docs

If you made any of the contrib/ programs, as the root user: 

make -C contrib/<SUBDIR-NAME> install
[Tip]

Tip

If you only intend to use PostgreSQL as a client to connect to a server on another machine, your installation is complete and you should not run the remaining commands.

Initialize a database cluster with the following commands issued by the root user: 

install -v -dm700 /srv/pgsql/data &&
install -v -dm755 /run/postgresql &&
chown -Rv postgres:postgres /srv/pgsql /run/postgresql

Now, initialize the database as the root user: 

su - postgres -c '/usr/bin/initdb -D /srv/pgsql/data'

Command Explanations

sed -i ...: This sed changes server socket location from /tmp to /run/postgresql.

--enable-thread-safety: This switch makes the client libraries thread-safe by allowing concurrent threads in libpq and ECPG programs to safely control their private connection handles.

--with-openssl: builds the package with support for OpenSSL encrypted connections.

--with-perl: builds the PL/Perl server-side language.

--with-python: builds the PL/Python server-side language. Add PYTHON=/usr/bin/python2 for Python2 support, otherwise Python3 is used by default.

--with-tcl: builds the PL/Tcl server-side language.

Configuring PostgreSQL

Config Files

$PGDATA/pg_ident.con, $PGDATA/pg_hba.conf, and $PGDATA/postgresql.conf

The PGDATA environment variable is used to distinguish database clusters from one another by setting it to the value of the directory which contains the cluster desired. The three configuration files exist in every PGDATA/ directory. Details on the format of the files and the options that can be set in each can be found in /usr/share/doc/postgresql-12.4/html/index.html.

Systemd Unit

Install the postgresql.service unit included in the blfs-systemd-units-20200828 package: 

make install-postgresql

Starting the PostgreSQL Server and Creating a Sample Database

The database server can be manually started with the following command (as the root user): 

su - postgres -c '/usr/bin/postgres -D /srv/pgsql/data > \
                  /srv/pgsql/data/logfile 2>&1 &'
[Note]

Note

If you are scripting this part, you should wait for the server to start before going on, by adding for example sleep 2 after the above command.

The instructions below show how to create a database, add a table to it, insert some rows into the table and select them, to verify that the installation is working properly. Still as user root, issue: 

su - postgres -c '/usr/bin/createdb test' &&
echo "create table t1 ( name varchar(20), state_province varchar(20) );" \
    | (su - postgres -c '/usr/bin/psql test ') &&
echo "insert into t1 values ('Billy', 'NewYork');" \
    | (su - postgres -c '/usr/bin/psql test ') &&
echo "insert into t1 values ('Evanidus', 'Quebec');" \
    | (su - postgres -c '/usr/bin/psql test ') &&
echo "insert into t1 values ('Jesse', 'Ontario');" \
    | (su - postgres -c '/usr/bin/psql test ') &&
echo "select * from t1;" | (su - postgres -c '/usr/bin/psql test')

When you are done with testing, you can shut down the server, by issuing as root: 

su - postgres -c "/usr/bin/pg_ctl stop -D /srv/pgsql/data"

Contents

Installed Programs: clusterdb, createdb, createuser, dropdb, dropuser, ecpg, initdb, pg_archivecleanup, pg_basebackup, pg_checksums, pg_config, pg_controldata, pg_ctl, pg_dump, pg_dumpall, pg_isready, pg_receivewal, pg_recvlogical, pg_resetwal, pg_restore, pg_rewind, pg_test_fsync, pg_test_timing, pg_upgrade, pg_waldump, pgbench, postgres, postmaster (deprecated), psql, reindexdb, vacuumdb, optionally, if Tcl support has been built, pltcl_delmod, pltcl_listmod, pltcl_loadmod, and optionally (in contrib/) oid2name, pg_standby, vacuumlo, and many others
Installed Libraries: libecpg.{so,a}, libecpg_compat.{so,a}, libpgcommon.a, libpgcommon_shlib.a, libpgfeutils.a, libpgport.a, libpgport_shlib.a, libpgtypes.{so,a}, libpq.{so,a}, various charset modules, and optionally programming language modules under /usr/lib/postgresql
Installed Directories: /usr/include/{libpq,postgresql}, /usr/lib/postgresql, /usr/share/{doc/postgresql-12.4,postgresql}, and /srv/pgsql

Short Descriptions

clusterdb

is a utility for reclustering tables in a PostgreSQL database.

createdb

creates a new PostgreSQL database.

createuser

defines a new PostgreSQL user account.

dropdb

removes a PostgreSQL database.

dropuser

removes a PostgreSQL user account.

ecpg

is the embedded SQL preprocessor.

initdb

creates a new database cluster.

oid2name

resolves OIDs (Object IDs) and file nodes in a PostgreSQL data directory.

pg_archivecleanup

cleans up PostgreSQL WAL (write-ahead log) archive files.

pg_basebackup

takes base backups of a running PostgreSQL cluster.

pg_checksums

enables, disables, or checks data checksums in a PostgreSQL database cluster.

pg_config

retrieves PostgreSQL version information.

pg_controldata

returns information initialized during initdb, such as the catalog version and server locale.

pg_ctl

controls stopping and starting the database server.

pg_dump

dumps database data and metadata into scripts which are used to recreate the database.

pg_dumpall

recursively calls pg_dump for each database in a cluster.

pg_isready

checks the connection status of a PostgreSQL server.

pg_receivewal

is used to stream write-ahead logs from a PostgreSQL server.

pg_recvlogical

controls PostgreSQL logical decoding streams.

pg_resetwal

resets the write-ahead log and other control information of a PostgreSQL database cluster.

pg_restore

creates databases from dump files created by pg_dump.

pg_rewind

synchronizes a PostgreSQL data directory with another data directory that was forked from the first one.

pg_standby

supports the creation of a PostgreSQL warm standby server.

pg_test_fsync

determines fastest wal_sync method for PostgreSQL.

pg_test_timing

measures timing overhead.

pg_upgrade

upgrades a PostgreSQL server instance.

pg_waldump

displays a human-readable rendering of the write-ahead log of a PostgreSQL database cluster.

pgbench

runs a benchmark test on PostgreSQL.

pltcl_delmod

is a support script used to delete a module from a PL/Tcl table. The command requires the Pgtcl package to be installed also.

pltcl_listmod

is a support script used to list the modules in a PL/Tcl table. The command requires the Pgtcl package to be installed also.

pltcl_loadmod

is a support script used to load a module into a PL/Tcl table. The command requires the Pgtcl package to be installed also.

postgres

is the PostgreSQL database server.

postmaster

(deprecated, a symlink to postgres) is a multi-user database daemon.

psql

is a console based database shell.

reindexdb

is a utility for rebuilding indexes in a database.

vacuumdb

compacts databases and generates statistics for the query analyzer.

vacuumlo

removes orphaned large objects from a PostgreSQL database.

libecpg.{so,a}

contains functions to support embedded SQL in C programs.

libecpg_compat.{so,a}

is the ecpg compatibility library.

libgport.a

is the port-specific subsystem of the Postgres backend.

libpgtypes.{so,a}

contains functions for dealing with Postgres data types.

libpq.{so,a}

is the C programmer's API to Postgres.

Last updated on 2020-08-17 15:12:09 -0700