pg_statviz
- This Release
- pg_statviz 0.7.0
- Date
- Status
- Testing
- Other Releases
- Abstract
- PostgreSQL stats visualization over time
- Description
- pg_statviz is a minimalist extension and utility pair for time series analysis and visualization of PostgreSQL internal statistics.
- Released By
- vyruss
- License
- PostgreSQL
- Resources
- Special Files
- Tags
Extensions
- pg_statviz 0.7.0
- PostgreSQL stats visualization over time
README
Contents
pg_statviz
pg_statviz is a minimalist extension and utility pair for time series analysis and visualization
of PostgreSQL internal statistics.
Created for snapshotting PostgreSQL’s cumulative and dynamic statistics and performing time series analysis on them. The accompanying utility can produce visualizations for selected time ranges on the stored stats snapshots, enabling the user to track PostgreSQL performance over time and potentially perform tuning or troubleshooting.
Design Philosophy
Designed with the K.I.S.S. and
UNIX philosophies in mind, pg_statviz aims to be
a modular, minimal and unobtrusive tool that does only what it’s meant for: create snapshots
of PostgreSQL statistics for visualization and analysis. To this end, a utility is provided for
retrieving the stored snapshots and creating with them simple visualizations using
pandas and Matplotlib.
Installing the extension
Red Hat Enterprise Linux (v8.0+) / Fedora (37+)
-
Configure the PostgreSQL Yum repository for your Linux distribution, as explained here.
-
Use
dnforyumto install the extension for your PostgreSQL version:sudo dnf install pg_statviz_extension-<pg_version> OR sudo yum install pg_statviz_extension-<pg_version>
PGXN (PostgreSQL Extension Network)
The extension is available on PGXN.
To install from PGXN, either download the zip file and install manually or use the PGXN Client to install:
pgxn install pg_statviz
Manual installation
To install manually, clone this repository locally:
git clone https://github.com/vyruss/pg_statviz.git
This will install the extension in the appropriate location for your system ($SHAREDIR/extension):
cd pg_statviz
sudo make install
Enabling the extension
The extension can now be enabled inside the appropriate database like this, e.g. from psql:
\c mydatabase
CREATE EXTENSION pg_statviz;
This will create the needed tables and functions under schema pgstatviz (note the lack of
underscore in the schema name).
Installing the utility
The visualization utility can be installed from PyPi:
pip install pg_statviz
The utility is also available in the
PostgreSQL Yum Repository and can be installed
using dnf or yum:
sudo dnf install pg_statviz
OR
sudo yum install pg_statviz
Requirements
Python 3.9+ is required for the visualization utility.
Usage
The extension can be used by superusers, or any user that has pg_monitor role privileges. To take
a snapshot, e.g. from psql:
SELECT pgstatviz.snapshot();
NOTICE: created pg_statviz snapshot
snapshot
-------------------------------
2024-06-27 11:04:58.055453+00
(1 row)
Older snapshots and their associated data can be removed using any time expression. For example, to remove data more than 90 days old:
DELETE FROM pgstatviz.snapshots
WHERE snapshot_tstamp < CURRENT_DATE - 90;
Or all snapshots can be removed like this:
SELECT pgstatviz.delete_snapshots();
NOTICE: truncating table "snapshots"
NOTICE: truncate cascades to table "buf"
NOTICE: truncate cascades to table "conf"
NOTICE: truncate cascades to table "conn"
NOTICE: truncate cascades to table "lock"
NOTICE: truncate cascades to table "io"
NOTICE: truncate cascades to table "wait"
NOTICE: truncate cascades to table "wal"
NOTICE: truncate cascades to table "db"
delete_snapshots
------------------
(1 row)
The pg_monitor role can be assigned to any user:
GRANT pg_monitor TO myuser;
Scheduling
Periodic snapshots can be set up with any job scheduler. For example with cron:
crontab -e -u postgres
Inside the postgres user’s crontab, add this line to take a snapshot every 15 minutes:
*/15 * * * * psql -c -d mydatabase "SELECT pgstatviz.snapshot()" >/dev/null 2>&1
Visualization
Potentially very large numbers of data points can be visualized with the aid of pandas resampling, displaying the mean value over 100 plot points as a default.
The visualization utility can be called like a PostgreSQL command line tool:
pg_statviz --help
usage: pg_statviz [--help] [--version] [--dbname DBNAME] [-h HOSTNAME] [--port PORT]
[-u USERNAME] [--password] [--daterange FROM TO] [-o OUTPUTDIR]
{analyze,buf,cache,checkp,conn, io,lock,tuple,wait,wal,xact} ...
run all analysis modules
positional arguments:
{analyze,buf,cache,checkp,conn,io,lock,tuple,wait,wal,xact}
analyze run all analysis modules
buf run buffers written analysis module
cache run cache hit ratio analysis module
checkp run checkpoint analysis module
conn run connection count analysis module
io run I/O analysis module
lock run locks analysis module
tuple run tuple count analysis module
wait run wait events analysis module
wal run WAL generation analysis module
xact run transaction count analysis module
options:
--help
--version show program's version number and exit
-d DBNAME, --dbname DBNAME
database name to analyze (default: 'myuser')
-h HOSTNAME, --host HOSTNAME
database server host or socket directory (default: '/var/run/postgresql')
-p PORT, --port PORT database server port (default: '5432')
-U USERNAME, --username USERNAME
database user name (default: 'myuser')
-W, --password force password prompt (should happen automatically) (default: False)
-D FROM TO, --daterange FROM TO
date range to be analyzed in ISO 8601 format e.g. 2024-01-01T00:00
2024-01-01T23:59 (default: [])
-O OUTPUTDIR, --outputdir OUTPUTDIR
output directory (default: -)
Specific module usage
pg_statviz conn --help
usage: pg_statviz conn [-h] [-d DBNAME] [--host HOSTNAME] [-p PORT] [-U USERNAME] [-W]
[-D FROM TO] [-O OUTPUTDIR] [-u [USERS ...]]
run connection count analysis module
options:
-h, --help show this help message and exit
-d DBNAME, --dbname DBNAME
database name to analyze (default: 'myuser')
--host HOSTNAME database server host or socket directory (default: '/var/run/postgresql')
-p PORT, --port PORT database server port (default: '5432')
-U USERNAME, --username USERNAME
database user name (default: 'myuser')
-W, --password force password prompt (should happen automatically) (default: False)
-D FROM TO, --daterange FROM TO
date range to be analyzed in ISO 8601 format e.g. 2024-01-01T00:00
2024-01-01T23:59 (default: [])
-O OUTPUTDIR, --outputdir OUTPUTDIR
output directory (default: -)
-u [USERS ...], --users [USERS ...]
user name(s) to plot in analysis (default: [])
Example:
pg_statviz buf --host localhost -d postgres -U postgres -D 2024-06-24T23:00 2024-06-26
Produces:
Schema
The pg_statviz extension stores its data in the following tables:
Table | Description
— | —
pgstatviz.snapshots | Timestamped snapshots
pgstatviz.buf | Buffer, checkpointer and background writer data
pgstatviz.conf | PostgreSQL server configuration data
pgstatviz.conn | Connection data
pgstatviz.db | PostgreSQL server and database statistics
pgstatviz.io | I/O stats data
pgstatviz.lock | Locks data
pgstatviz.wait | Wait events data
pgstatviz.wal | WAL generation data
Export data
To dump the captured data, e.g. for analysis on a different machine, run:
pg_dump -d <dbname> -a -O -t pgstatviz.* > pg_statviz_data.dump
Load it like this on the target database (which should have pg_statviz installed) :
psql -d <other_dbname> -f pg_statviz_data.dump
Alternatively, pg_statviz internal tables can also be exported to a tab separated values (TSV) file
for use by other tools:
psql -d <dbname> -c "COPY pgstatviz.conn TO STDOUT CSV HEADER DELIMITER E'\t'" > conn.tsv
These can then be loaded into another database like this, provided the tables exist (installing the extension will create them):
psql -d <other_dbname> -c "COPY pgstatviz.conn FROM STDIN CSV HEADER DELIMITER E'\t'" < conn.tsv