=head1 NAME

pgCluu - PostgreSQL Cluster utilization

=head1 DESCRIPTION

pgCluu is a PostgreSQL performance monitoring and auditing tool.

It is a Perl program used to perform a full audit of a PostgreSQL Cluster
and System performance. It is divided in two parts:

- A collector used to grab statistics on the PostgreSQL cluster using
the psql command line utility and sar from the sysstat package.

- A pure Perl grapher that will generate all HTML and charts output without
any requirements.

If you don't need system utilization reports or don't want to install the
sysstat package, you can disable it at command line. You will only have
reports about your PostgreSQL Cluster. If you are running pgCluu from a
central server using option -h to monitor remotely a PostgreSQL Cluster,
the call to sar is automatically disabled.

If you just want to have system utilization reports or generate graphs from
a sar data file, it's also possible.


=head1 SYNOPSIS

PostgreSQL and System metrics collector.

	pgcluu_collectd [options] output_dir

Report generator.

	pgcluu [options] -o report_dir input_dir


=head1 REQUIREMENT

pgCluu comes with two Perl scripts. You need a modern Perl distribution, the
psql client and the sar command line utility (sysstat). The sysstat package is
optional, you can still use pgCluu to generate reports about your PostgreSQL
Cluster without it.

Charts are rendered using a Javascript library so you don't need anything else.
Your browser will do all the work.

=head1 INSTALLATION

=head2 Installation from package

Installation of pgCluu can be done through the PostgreSQL Global Development
Group (PGDG) repositories. See how to install the PGDG repositories at the
following URLs for Debian and Ubuntu:

	https://wiki.postgresql.org/wiki/Apt

and Redhat, CentOs, Fedora, Scientific Linux and Oracle Enterprise Linux:

	https://yum.postgresql.org/

Once it is done you can simply install pgCluu with commands:

	sudo apt install pgcluu
	sudo yum install pgcluu

Look at the package information to know where files are specifically
installed. See next two chapters to see which default installation
paths are used.

=head2 Installation from sources

Download the tarball from SourceForge and unpack the archive:

        tar xzf pgcluu-3.x.tar.gz
        cd pgcluu-3.x/
        perl Makefile.PL
        make && sudo make install

This will copy the Perl scripts pgcluu_collectd and pgcluu into /usr/local/bin
directory and the man page to /usr/local/share/man/man1/pgcluu.1p.gz.
Those are the default installation directories for 'site' install on some
well-known distribution but the path could change.

If you want to install all under /usr location, use INSTALLDIRS='vendor' as
an argument of Makefile.PL. The script will be installed into /usr/bin/pgcluu
and the manpage into /usr/share/man/man1/pgcluu.1p.gz.

For example, to install everything just like Debian does, proceed as follows:

        perl Makefile.PL INSTALLDIRS=vendor

By default INSTALLDIRS is set to site.

The directory where statistics will be saved is /var/lib/pgcluu/data and the
default directory for reports is /var/lib/pgcluu/report.

The CGI script is installed into /var/lib/cgi-bin/pgcluu.cgi and the Apache
configuration file into /etc/apache/conf-available/pgcluu.conf. This file
allow acces to resources files (CSS and JS files) from installation directory
/usr/local/share/pgcluu/rsc/. Access is granted to local user only by default.

All scripts (pgcluu_collectd, pgcluu and pgcluu.cgi) are reading configuration
file from /usr/local/etc/pgcluu.conf. This file is mainly use by the CGI script
but some directives are dedicated to pgcluu_collectd and pgcluu script to
define the retention days for example.

=head2 Custom installation

The installation of pgCluu can be fully customized through environment
variables (RSCDIR,CGIDIR,CONFDIR,PIDDIR,STATDIR,APACHECONF,MANDIR,
DOCDIR,SYSTEMDDIR,RETENTION). These variables are passed to Makefile.PL
as command line arguments or can be exported as environment variables
before running "perl Makefile.PL".

The default values for these variables are:

    DESTDIR     => /usr/local
    INSTALLDIRS => site
    CONFDIR     => DESTDIR/etc
    PIDDIR      => /var/run/postgres
    STATDIR     => /var/lib/pgcluu/data
    REPORTDIR   => /var/lib/pgcluu/data
    RSCDIR      => DESTDIR/share/pgcluu
    CGIDIR      => /usr/lib/cgi-bin
    APACHECONF  => /etc/apache2/conf-available
    MANDIR      => DESTDIR/share/man
    DOCDIR      => DESTDIR/share/doc
    SYSTEMDIR   => DESTDIR/lib/systemd/system
    RETENTION   => 0

If INSTALLDIRS is set to 'vendor':

    CONFDIR     => /etc
    DESTDIR     => /usr

The configuration file is auto-generated by the Makefile.PL script and
saved into CONFDIR/pgcluu.conf. If the destination file exists it is
not overridden. The file is also saved as example in the directory
DOCDIR/pgcluu/examples/pgcluu.conf.dist

The directory where pgcluu_colletd will store statistics is defined
with STATDIR which is by default /var/lib/pgcluu/data. The directory
where pgcluu will generate static html reports is defined by REPORTDIR.
The default is /var/lib/pgcluu/report. Both directory must be owned by
the postgres user.

The man page is saved as DESTDIR/share/man/pgcluu.1p.gz and a symbolic
link pgcluu_collectd.1p.gz is created to this file. The documentation,
README, changelog.gz, LICENSE files are saved under DESTDIR/share/doc/.

For the CGI mode, the resources (css and js files from the cgi-bin/rsc)
are saved under the DESTDIR/share/pgcluu/rsc directory. The CGI script
is saved under /usr/lib/cgi-bin/pgcluu.cgi. The Apache configuration
file under /etc/apache2/conf-available/pgcluu.conf with a symbolic link
/etc/apache2/conf-enabled/pgcluu.conf created to this file. Its content:

    Alias /pgcluu RSCDIR/
    <Directory RSCDIR/>
	Options FollowSymLinks MultiViews
	AllowOverride None
	Require local
	#Require ip 192.1.168.0/24
    </Directory>

The systemd files (pgcluu_collectd.service,pgcluu.service,pgcluu.timer)
are saved as examples into DOCDIR/pgcluu/examples/ and into the systemd
directory SYSTEMDDIR/

The right path to the configuration file is set into all scripts pgcluu,
pgcluu_collectd and pgcluu.cgi. The path where the pid file must be
saved is replaced into pgcluu_collectd with the value of PIDFILE
variable.

Paths to scripts, pid directory, statistics and reports are replaced
in all systemd service files following the values of the environment
variable explain here.

=head1 USAGE

=head3 Manually

See next two chapters for a complete description of the command line options.
For the impatient, here some simple commands that could be run as postgres
user:

        mkdir /tmp/stat_db1/
        pgcluu_collectd -D -i 60 /tmp/stat_db1/
	LOG: Detach from terminal with pid: 11323

or with more options

        pgcluu_collectd -D -i 60 /tmp/stat_db1/ -h 10.10.1.1 -U postgres -d mydb
	LOG: Detach from terminal with pid: 14671

wait some time and activity on your PostgreSQL Cluster...
Then stop the pgcluu_collectd daemon and generate the report:

        pgcluu_collectd -k
	LOG: Received terminating signal.
	mkdir /tmp/report_db1/
	pgcluu -o /tmp/report_db1/ /tmp/stat_db1/

You should obtain something like example at http://pgcluu.darold.net/example/

By default all javascript, css and the webfont fontawesome are automatically
generated into the output directory if those files does not already exits.

=head3 Using systemd unit files

pgcluu comes with systemd service files:

    - pgcluu_collectd.service: execute pgcluu_collectd as a daemon to collect statistics.
    - pgcluu.service: execute pgcluu to generate reports.
    - pgcluu.timer: run periodically pgcluu.service

These files are installed automatically by the install script or the package
into /lib/systemd/system/. To activate these services proceed as follow:

	systemctl daemon-reload
	systemctl enable pgcluu_collectd.service
	systemctl enable pgcluu.service
	systemctl enable pgcluu.timer
	systemctl start pgcluu_collectd.service
	systemctl start pgcluu.timer

Be warn that storing indefinitely statistics with pgcluu_collectd can fill
you disk space in the short or medium term. You have to remove obsolete
statistics manually using a cron job or using the embedded retention feature
by adding option '--retention ndays' to pgcluu_collectd call or by changing
the value of STATS_COLLECTD_RETENTION configuration directive in file
/usr/local/etc/pgcluu.conf or /etc/pgcluu.conf file following your installation.
You can also set STATS_REPORT_RETENTION to limit the retention of reports
directories or use option '--retention ndays' with pgcluu.

If you want to use the CGI mode you also have activate pgcluu caching by
enabling value STATS_REPORT_CACHING in the configuration file and using
pgcluu.service+pgcluu.timer. If you don"t want to use systemd you can
simply run pgcluu script with the -C option and execute it periodically
through a cron job.

Note that the systemd service files set the privilege to the data and report
directory to user postgres and group www-data. By this way reports are readable
through an httpd server for static reports and data are readable through the
CGI if enabled. Command executed by the pgcluu_collectd.service file (daemon part)
are:

	/bin/mkdir -p $STATDIR
	/bin/chown postgres:www-data $STATDIR
	/bin/chmod u=rwX,g=rsX,o= $STATDIR

The pgcluu.service file (client part) execute commands:

	/bin/mkdir -p $REPORTDIR
	/bin/chown postgres:www-data $REPORTDIR
	/bin/chmod u=rwX,g=rsX,o= $REPORTDIR

In case you don't want to use systemd service files you will have to execute
these commands manually before tunning pgCluu.

=head1 COLLECTING STATISTICS

To generate reports about your PostgreSQL Cluster Utilization you must collect
statistics before. pgcluu_collectd is here for that. It can be run in a daemon
mode (option -D) or in interactive mode for debugging purpose. All you need is
to provide a directory where data will be stored. Statistics will be pooled at
a default interval of 60 seconds, using option -i you can customize it. See
below for a complete list of command line options. 

=head2 pgcluu_collectd usage

usage: pgcluu_collectd [options] output_dir

	output_dir: full path to directory where pgcluu_collectd will
		    store statistics.

options:

  -B, --enable-buffercache enable buffercache statistics if pg_buffercache
			   extension is installed.
  -c, --capture            create a snapshot of the PostgreSQL installation
                           into tmp/pgcluu_capture.tar.gz.
  -C, --end-counter=NUM    terminate program after NUM reports.
  -d, --dbname=DATABASE    database name to connect to. Default to current user.
  -D, --daemonize          detach from console and enter in daemon mode.
  -E, --end-after=SECOND   self terminate program after a given number of seconds.
                           Can be written: 7200 or 120M or 2H, for days use 7D for
                           example to stop collecting data after seven days. 
  -f, --pid-file=FILE      path to pid file. Default: /var/run/postgresql/pgcluu_collectd.pid.
  -h, --host=HOSTNAME      database server host or socket directory
  -i, --interval=NUM       time to wait between runs
  -k, --kill		   stop current pgcluu_collectd running daemon.
  -m, --metric=METRIC      set a coma separated list of metrics to perform.
  -M, --max-size=SIZE      self terminate program when the size of the output dir
                           exceed a given size. Can be written: 2GB or 2000MB. 
  -p, --port=PORT          database port(s) to connect to. Defaults to 5432.
  -P, --psql=BIN           path to the psql command. Default: psql.
  -Q, --no-statement       do not collect queries statistics from pg_stat_statements.
  -r, --rotate-daily       force daily rotation of data files.
  -R, --rotate-hourly      force hourly rotation of data files.
  -s, --sar=BIN            path to sar sysstat command. Default: sar.
  -S, --disable-sar        disable collect of system statistics with sar.
  -T, --no-tablespace      disable lookup at tablespace when the connect user
			   is not superuser to avoid printing an error message.
  -U, --dbuser=USERNAME    database user to connect as. Default to current user.
  -v, --verbose            Print out debug informations.
  -V, --version            Show pgcluu_collectd version and exit.
  -W, --password=pass      database password.
  -z, --compress           force compression of rotated data files.
  --included-db=DATABASE   collect statistics only for those databases present
                           in a comma separated list of database names.
  --list-metric            list available metrics actions that can be performed.
  --sysinfo                get operating system information and exit (sysinfo.txt).
  --no-sysinfo             do not collect operating system information at all. 
  --no-database            do not collect database statistics at all.
  --pgbouncer-args=OPTIONS Option to used to connect to the pgbouncer system
			   database. Ex: -p 6432 -U postgres -h 192.168.1.100
                           You must at least give one parameter to enable
                           pgbouncer monitoring.
  --sar-file=FILE          path to sar output data file for sysstat stats
                           Default to output_dir/sar_stats.dat.
  --stat-type all|user     Set stats tables to read. Values: 'all' or 'user' to
			   look at pg_stat_(all|user) tables. Default: user.
  --pgversion X.Y          force the PostgreSQL version to the given value.
  --pgservice NAME         Name of service inside of the pg_service.conf file.
  --exclude-time RANGE     exclude a laps of time by giving the start and end
			   hours.
  --cron-user=USERNAME     collect crontab settings for the given username (in
                           this case pgcluu_collectd need to be run as root).
                           Default is to use USERNAME environment variable or
                           postgres when it is not defined.
  --package-list=CMD       command to list PostgreSQL packages. Default is to
                           autodetect package type and using command 'rpm -qa'
                           or 'dpkg -l'. If you have an other system you can
                           set a custom command. A filter on keyword 'postgres'
			   is appended to the command: ' | grep postgres'.
  --retention NDAYS        number of rolling days to keep in data directory in
                           incremental mode. Default is to store indefinitely.
  --help                   print usage

Use those options to execute sar on the remote host defined by the -h option,
otherwise it will be executed locally:

  --enable-ssh             activate the use of ssh to run sysstat remotely.
  --ssh-program ssh        path to the ssh program to use. Default: ssh.
  --ssh-user username      connection login name. Default to running user.
  --ssh-identity file      path to the identity file to use.
  --ssh-timeout second     timeout to ssh connection failure. Default 10 seconds.
  --ssh-options  options   list of -o options to use for the ssh connection. Options
			   always used:
				 -o ConnectTimeout=$ssh_timeout
				 -o PreferredAuthentications=hostbased,publickey

For example, as postgres user to monitor locally a full PostgreSQL cluster:

	mkdir /tmp/stat_db1/
	pgcluu_collectd -D -i 60 /tmp/stat_db1/

to collect statistics from pgbouncer too, and limit database statistics to a single
database:

	pgcluu_collectd -D -i 60 /tmp/stat_db1/ -h 10.10.1.1 -U postgres -d mydb 
		--pgbouncer-args='-p 5342'

to disable statistics collect between 22:30 and 06:30 the next day:

	pgcluu_collectd -D -i 60 /tmp/stat_db1/ --exclude-time "22:30-06:30"

to collect statistics from a remote server:

	pgcluu_collectd -D -i 60 /tmp/stat_db1/ -h 10.0.0.1 -U postgres --disable-sar

the same but with collecting system statistics using remote sar calls:

	pgcluu_collectd -D -i 60 /tmp/stat_db1/ -h 10.0.0.1 -U postgres --enable-ssh 
		--ssh-user postgres --ssh-identity /var/lib/postgresql/.ssh/id_rsa.pub

You may need a .pgpass and be able to establish passwordless ssh connections to be
able to collect statistics from remote hosts.

Then after some time and activities on the database, stop the daemon as follow:

        pgcluu_collectd -k

or by sending sigterm to the pgcluu_collectd's pid.

You can run the collector in incremental mode using a daily or a hourly statistics
rotation:

	pgcluu_collectd -D -i 60 /tmp/stat_db1/ --rotate-daily

On a server with huge activity you may want to use --rotate-hourly and compression
mode with --compress option. If you have limited disk space you can restrict the
retention time of statistics files using option --retention with the storage day
limit.

=head2 Statistics files

The output directory with all statistics collected should look likes:

	/tmp/stat_db1/
	|-- commit_memory.csv
	|-- end-pg_statio_user_indexes.csv
	|-- end-pg_statio_user_sequences.csv
	|-- end-pg_statio_user_tables.csv
	|-- end-pg_stat_user_functions.csv
	|-- end-pg_stat_user_indexes.csv
	|-- end-pg_stat_user_tables.csv
	|-- end-pg_stat_xact_user_functions.csv
	|-- end-pg_stat_xact_user_tables.csv
	|-- fs_stat_use.csv
	|-- pg_class_size.csv
	|-- pg_database_size.csv
	|-- pg_db_role_setting.csv
	|-- pg_hba.conf
	|-- pg_ident.conf
	|-- pg_nondefault_settings.csv
	|-- pg_prepared_xact.csv
	|-- pg_settings.csv
	|-- pg_stat_archiver.csv
	|-- pg_stat_bgwriter.csv
	|-- pg_stat_connections.csv
	|-- pg_stat_count_indexes.csv
	|-- pg_stat_database_conflicts.csv
	|-- pg_stat_database.csv
	|-- pg_stat_hash_indexes.csv
	|-- pg_stat_invalid_indexes.csv
	|-- pg_statio_user_indexes.csv
	|-- pg_statio_user_sequences.csv
	|-- pg_statio_user_tables.csv
	|-- pg_stat_locks.csv
	|-- pg_stat_missing_fkindexes.csv
	|-- pg_stat_redundant_indexes.csv
	|-- pg_stat_replication.csv
	|-- pg_stat_unlogged.csv
	|-- pg_stat_unused_indexes.csv
	|-- pg_stat_user_functions.csv
	|-- pg_stat_user_indexes.csv
	|-- pg_stat_user_tables.csv
	|-- pg_stat_xact_user_functions.csv
	|-- pg_stat_xact_user_tables.csv
	|-- pg_tablespace_size.csv
	|-- pg_xlog_stat.csv
	|-- postgresql.auto.conf
	|-- postgresql.conf
	|-- sar_stats.dat
	|-- sysinfo.txt

Then now you can proceed with pgcluu to generate reports.

=head2 Rotation and compression

When used the --rotate-daily or --rotate-hourly commands line option will force
pgcluu_collectd to rotate daily or hourly all statistic's files. In this case,
statistics files will be created in a subdirectory based on rotation frequency,
output_dir/year/month/day[/hour]. This is called the incremental mode.

To save filesystem space it is possible to enable compression of all rotated
files during the rotation process. Just activate the -z or --compress command
line option. You can also use the --retention option to set the storage time
limit in days.

=head2 Incremental mode

This mode is enabled when --rotate-daily or --rotate-hourly command line
options are used. It allow pgcluu to build reports incrementally by days
or hours. In this mode you don't have to build reports per day or hour
pgcluu will do the work automatically, just give it the top statistics
directory.

	pgcluu -o /var/www/pgcluu/reports/ /var/lib/pgcluu/data/

pgcluu will detect that --rotate-daily or --rotate-hourly have been used
to collect data and generate reports for each day or hours stored. Previous
directories already processed will not be processed again unless this was the
the last one.

The daily or hourly basis statistic storage also allow the use of the CGI
script pgcluu.cgi to have dynamic reports and temporal search. See "Using
dynamic mode" chapter.

When used the --rotate-daily or --rotate-hourly commands line option will force
pgcluu_collectd to rotate daily or hourly all statistic's files. In this case,
statistics files will be created in a subdirectory based on rotation frequency,
output_dir/year/month/day[/hour]. This is called the incremental mode.

To save filesystem space it is possible to enable compression of all rotated
files during the rotation process. Just activate the -z or --compress command
line option. You can also use the --retention option to set the storage time
limit in days.

=head2 Capture mode

The goal of this mode is to be able to obtain a simple report about the
PostgreSQL installation without collected metrics others than database
and tablespace size. This report can be use by ITs to better understand
the configuration and things that need to be tuned.

To enable this mode, just run pgcluu_collectd with the single option -c
or --capture. Other command line options will not be taken in account.
pgcluu_collectd will create e temporary directory /tmp/pgcluu_capture
to store temporary data and will removed if after building a compressed
tar archive: /tmp/pgcluu_capture.tar.gz. This is this archive that can
be used with pgcluu to build a snapshot report of the instance. pgcluu
will automatically detect this mode.

=head1 GENERATING REPORTS

=head2 Static HTML reports

To generate a pgCluu report about a PostgreSQL Cluster you must, at least,
have a directory that contains all data files generated by pgcluu_collectd
or pgstats. In this directory, if you have a file named sar_stats.dat or
sadc_stats.dat for binary sadc data file, it will be taken to build report
about system utilization. If you just want to make a report from a sar file
use the -i or -I options.

usage: pgcluu [options] [-i sar_file | -I sadc_file] [input_dir]

	input_dir: directory where pgcluu_collectd or pgstats and sar data
		   files are stored.

options:
  -b, --begin  datetime      start date/time for the data to be parsed.
  -C, --cache                generate cache files only (.bin), no html output.
  -d, --db-only dbname       only report for the whole cluster and the given
                             database name. You can use it multiple time or
                             give a comma separated list of database name.
  -D, --device-only dev      only report I/O stats for a particular device
                             You can use it multiple time or give a comma
                             separated list of device name, ex: sda,sdc.
  -e, --end    datetime      end date/time for the data to be parsed.
  -i, --sar-file=FILE        path to the sar text data file to read to generate
                             system reports. Default to input_dir/sar_stats.dat.
  -I, --sadc-file=FILE       sadc binary data file to read to generate system
                             reports. Default to input_dir/sadc_stats.dat.
  -n, --top-number           Top number of tables or indexes I/O stats to show.
                             Default is set to top 10. Set it to 0 to show all.
  -N, --network-only iface   only report stats for a particular network interface.
                             You can use it multiple times or give a comma separated
                             list of network interfaces, ex: eth0,eth1.
  -o, --output=DIR           output directory
  -r, --reverse-date         By default pgcluu look at mm/dd/yy format in sar file.
                             When enabled pgcluu will look at dd/mm/yy format.
  -s, --sadf=BIN             path to the sadf sysstat command used to read the
                             sadc binary data file. Default: /usr/bin/sadf.
  -S, --disable-sar          disable collect of system statistics with sar.
  -t, --with-table table     Only report for the whole tables and the given
                             table name. You can use it multiple time or
                             give a comma separated list of database name.
  -T, --no-table             Do not report statistics related to tables.
  -v, --verbose              Print out debug informations.
  -V, --version              Show pgcluu version and exit.
  -x, --external-menu        Save menu in menu.html and load it into each report
                             using w3-include-html attribut from w3.js. This will
			     only work if acces to HTML reports is through a Web
			     server, not using the file:// protocol.
  -z, --timezone +/-XX       Set the number of hour(s) from GMT of the timezone.
                             Use this to adjust date/time from the sar output,
                             pgcluu use GMT time to draw charts.
  -Z, --stats-timezone +/-XX Set the number of hour(s) from GMT of the timezone.
                             Use this to adjust date/time from the cluster and
                             system stats output, pgcluu use GMT time.
  --from-sa-file             instruct pgcluu that file specified by the -i option
                             uses the standard system activity daily data file.
  --charset                  used to set the HTML charset to be used.
                             Default: utf-8.
  --retention NDAYS          number of rolling days to keep in report directory.
                             Default is to store indefinitely.
  --help                     print usage

For example, you can generate all HTML reports from data files stored into
/tmp/stat_db1/ with the following commands:

        mkdir /tmp/report_db1/
        pgcluu -o /tmp/report_db1/ /tmp/stat_db1/

If you just want reports of some databases, use the following:

        pgcluu -o /tmp/report_db1/ /tmp/stat_db1/ --db-only "db1,db2,db3"

If you just want to create a report from a sar output file:

	sar -p -A 10 60 > /root/my_sar_file.txt
        pgcluu -o /tmp/report_sar/ -i /root/my_sar_file.txt

or from a daily sa file:

        sar -p -A -f /var/log/sa/sa18 > /root/my_sar_file.txt
        pgcluu -o /tmp/report_sar/ -i /root/my_sar_file.txt --from-sa-file

and from a sa binary file:

        pgcluu -o /tmp/report_sar/ -i /var/log/sysstat/sa22

or the sa text file if you don't have the same version of sysstat:

        pgcluu -o /tmp/report_sar/ -i /var/log/sysstat/sar23 --from-sa-file

If pgcluu_collectd have been run in incremental mode you can limit the number
of retention days used for the reports:

	pgcluu -o /tmp/report_sar/ /tmp/stat_db1/ --retention 30

A static report will be built for each day or hour following the rotation
used with pgcluu_collectd.

=head2 Dynamic reports (CGI)

Dynamics reports are build by a CGI script named pgcluu.cgi that can be
found in the cgi-bin repository of the source code. It allow you to select
the time period to build reports and to look at all differents reports for
this period just as with static HTML reports. After installation from sources
or binary packages the CGI might be found in /usr/lib/cgi-bin/pgcluu.cgi or
/var/www/cgi-bin/pgcluu.cgi following your distribution.

To use pgCluu in CGI mode, you need a Web server (here we use Apache) and
a cron task to build the cache periodically. 

First enable CGI mode.

	sudo a2enmod cgi
	sudo service apache2 restart

Then the CGI need to find the statistics directory where pgcluu_collectd
mostly /var/lib/pgcluu/data/. The content of this repository must be
readable by the Apache user (www-data).

Take care to restrict access to your server and the CGI as information
about your database and server are exposed in the reports.

The CGI script, pgcluu.cgi, use resources files (CSS and javascript). They
are stored in the cgi-bin/rsc/ directory of the source distribution. Install
this repository onto the DocumentRoot of your Web server, for example:

	sudo mkdir /var/www/pgcluu/
	sudo cp -rf cgi-bin/rsc /var/www/pgcluu/

Then edit /etc/pgcluu.conf, copy it from sources cgi-bin/pgcluu.conf if it
doesn't exists. Change the RSC_BASE and INPUT_DIR configuration directive
to match your installation. Here in our example:

	RSC_BASE	/pgcluu/rsc/
	INPUT_DIR	/var/lib/pgcluu/data

Now we can start the data collection. For the moment pgcluu.conf is only
read by the CGI pgcluu.cgi but this might change in the future.

To let pgCluu start collecting data, you can use the following command
(you can change it to however you like). We will need postgres user for this.

	sudo su - postgres
	/usr/local/bin/pgcluu_collectd -D -i 60 --rotate-daily /var/lib/pgcluu/data

This will rotate you data daily. This is also the default in the systemd
service file.

Plugging the CGI directly to the CSV statistics files will result in very slow
generation reports. To improve speed caching must be used, you must execute
periodically pgcluu in cache mode. Run it manually the first time

	/usr/local/bin/pgcluu --cache /var/lib/pgcluu/data

then add a cron task to execute the command each five or ten minutes:

	*/5 * * * * /usr/local/bin/pgcluu --cache /var/lib/pgcluu/data

If you are using systemd pgcluu.timer service then caching can be enabled
using STATS_REPORT_CACHING directive. Enabling this mode generate cache
files (*.bin) in the statistics directory and disable static HTML reports
generation.

To see your reports, go to the following URL:

	http://localhost/cgi-bin/pgcluu.cgi

Or change localhost by your fqdn server name.

Note that here pgcluu_collectd and pgcluu scripts are found in /usr/local/bin/
which is the default for an installation from sources but with an installation
from binary package you might find them into /usr/bin/.

The CGI mode allow you to select the period of time used to generate the
statistics reports. Using default pgcluu_collectd 60 seconds interval, a
daily graph will have 1440 points. Having too much timeseries to render
is not a good point for performances so we are limiting to the first seven
days of the selected period. This mean a maximum of 10080 points for one
week, this seems a safe limit. Feel free to increase or reduce the limit
following the server and client resources. This is controlled by

	MAX_RENDERED_DAYS       7

configuration directive in pgcluu.conf

=head1 LICENSE

Copyright (c) 2012-2019, Gilles Darold

pgCluu is licenced under the PostgreSQL Licence a liberal Open Source license,
similar to the BSD or MIT licenses. That mean that all parts of the program
are open source and free of charge.

	Permission to use, copy, modify, and distribute this software and its
	documentation for any purpose, without fee, and without a written agreement
	is hereby granted, provided that the above copyright notice and this
	paragraph and the following two paragraphs appear in all copies.

	IN NO EVENT SHALL Dalibo BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
	SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,
	ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
	Dalibo HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	Gilles Darold SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS,
	AND Gilles Darold HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,
	UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

This is the case for both, pgcluu_collectd and the grapher pgcluu programs.

=head1 AUTHORS

pgCluu is an original development of Gilles Darold.

Some parts of the collector are taken from pgstats a C program writen by
Guillaume Lelarge and especially the SQL queries including the compatibility
with all PostgreSQL versions. See https://github.com/gleu/pgstats

Btw pgCluu grapher is compatible with files generated by pgstats, sar and
sadc so you can use it independantly to graph those data. Some part of the
sar output parser are taken from SysUsage. See http://sysusage.darold.net/

