Run postgresqltuner.pl on each database and keep 3 copies of each database's report

run_pgtuner.sh

#!/usr/bin/env bash

# This script requires postgresqltuner.pl:
# apt install libdbd-pg-perl libdbi-perl perl-modules
# wget -O /usr/local/bin/postgresqltuner.pl https://postgresqltuner.pl
# chmod +x /usr/local/bin/postgresqltuner.pl

OUTPUT_DIR="/var/lib/postgresqltuner"
# Max number of files to keep for each database
MAX_COPIES=3
# Do not run against those databases
IGNORE_dbs=("postgres" "template0" "template1")

function remove_old_files {
	local db="$1"
	local count
	count="$(find "$OUTPUT_DIR" -name "${db}-*" | wc -l)"
	if [ "$count" -gt "$MAX_COPIES" ]; then
		while read -r file; do
			rm "$file"
		done < <(find "$OUTPUT_DIR" -name "${db}-*" | sort | head -"$((count - MAX_COPIES))")
	fi
}

if [ ! -d "$OUTPUT_DIR" ]; then
	mkdir -p "$OUTPUT_DIR"
	setfacl -d -m u:postgres:rwX "$OUTPUT_DIR"
	setfacl -m u:postgres:rwX "$OUTPUT_DIR"
fi

dbs="$(su -c "LC_ALL=C /usr/bin/psql -lqAx" postgres | awk -F\| '/^Name/{ print $2 }')"

for db in "${IGNORE_dbs[@]}"; do
	dbs="${dbs//$db/}"
done

for db in $dbs; do
	output="${OUTPUT_DIR}/${db}-$(date +"%Y%m%d")"
	su -c "/usr/local/bin/postgresqltuner.pl --database $db >$output 2>&1" postgres
	remove_old_files "$db"
done