wan
08c585d048
Serverless clients -> many short connections, few TPS. pool_mode= transaction, max_client_conn=300, default_pool_size=20 (+reserve 5) matching max_connections=30. max_prepared_statements=200 for ORM prepared statements. localhost-only until remote-access migration (roadmap 015). README table + notes updated.
113 lines
4.1 KiB
Bash
113 lines
4.1 KiB
Bash
#!/usr/bin/env bash
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# 013-install-pgbouncer - Connection pooling for serverless clients.
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#
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# Workload: a handful of TPS, but many (serverless) clients -> many short
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# connections. PgBouncer fronts PostgreSQL in transaction mode; PostgreSQL
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# itself keeps max_connections=30 (010). Server connections go over TCP
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# 127.0.0.1:5432 so the existing pg_hba `host ... scram-sha-256` line applies
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# unchanged (PgBouncer re-uses the client's SCRAM verifier from userlist.txt).
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#
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# Listens on 127.0.0.1:6432 ONLY - remote access is a later migration
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# (roadmap): flip listen_addr, populate userlist.txt with an app role, open
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# the firewall. Until then nothing can connect through it; that is expected.
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#
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# Populating userlist.txt when the app role exists (SCRAM pass-through):
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# runuser -u postgres -- psql -tAc \
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# "SELECT '\"'||rolname||'\" \"'||rolpassword||'\"' \
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# FROM pg_authid WHERE rolname='APP' AND rolpassword LIKE 'SCRAM%'" \
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# | sudo tee -a /etc/pgbouncer/userlist.txt && sudo systemctl reload pgbouncer
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#
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# up: install package (PGDG/Debian repo), write ini + empty userlist,
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# enable + restart service, verify it accepts connections
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# down: stop + disable service, purge package, remove config
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set -euo pipefail
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INI=/etc/pgbouncer/pgbouncer.ini
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USERLIST=/etc/pgbouncer/userlist.txt
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LOG=/var/log/postgresql/pgbouncer.log
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write_ini() {
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install -d -o postgres -g postgres -m 750 /etc/pgbouncer
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cat > "$INI" <<'EOF'
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;; managed by sysmig 013-install-pgbouncer - serverless connection pooler
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[databases]
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;; server side: TCP + scram against stock pg_hba (127.0.0.1/32 line)
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iwanhae = host=127.0.0.1 port=5432 dbname=iwanhae
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[pgbouncer]
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;; --- client side: localhost only until the remote-access migration ---
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listen_addr = 127.0.0.1
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listen_port = 6432
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unix_socket_dir = /var/run/postgresql
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auth_type = scram-sha-256
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auth_file = /etc/pgbouncer/userlist.txt
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admin_users = iwanhae
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;; --- pooling: many short serverless clients, few real workers ---
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pool_mode = transaction
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max_client_conn = 300
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default_pool_size = 20
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reserve_pool_size = 5
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reserve_pool_timeout = 3
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;; named prepared statements in transaction mode (ORMs need this, >=1.22)
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max_prepared_statements = 200
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ignore_startup_parameters = extra_float_digits
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;; --- server connection lifecycle ---
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server_reset_query = DISCARD ALL
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server_idle_timeout = 60
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;; --- process ---
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logfile = /var/log/postgresql/pgbouncer.log
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pidfile = /var/run/postgresql/pgbouncer.pid
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user = postgres
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EOF
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chown postgres:postgres "$INI"
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chmod 640 "$INI"
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}
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case "${1:-}" in
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up)
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if ! dpkg -s pgbouncer >/dev/null 2>&1; then
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export DEBIAN_FRONTEND=noninteractive
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apt-get update -qq
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apt-get install -y pgbouncer >/dev/null
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echo " pgbouncer installed"
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else
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echo " pgbouncer already installed"
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fi
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write_ini
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# empty placeholder; populated by the future remote-access migration
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touch "$USERLIST"
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chown postgres:postgres "$USERLIST"
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chmod 640 "$USERLIST"
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systemctl enable pgbouncer >/dev/null
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systemctl restart pgbouncer
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ok=0
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for _ in $(seq 1 10); do
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if pg_isready -h 127.0.0.1 -p 6432 -q 2>/dev/null; then ok=1; break; fi
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sleep 1
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done
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[[ $ok -eq 1 ]] || { echo "FATAL: pgbouncer not accepting on 127.0.0.1:6432 - check $LOG" >&2; exit 1; }
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echo " listening on 127.0.0.1:6432 (transaction pool, ready for userlist entries)"
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;;
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status)
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[[ -f $INI ]] || { echo "DRIFT $INI missing"; exit 1; }
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systemctl is-active --quiet pgbouncer || { echo "DRIFT pgbouncer service not active"; exit 1; }
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pg_isready -h 127.0.0.1 -p 6432 -q 2>/dev/null \
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|| { echo "DRIFT nothing accepting on 127.0.0.1:6432"; exit 1; }
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grep -q '^pool_mode = transaction' "$INI" || { echo "DRIFT pool_mode not transaction"; exit 1; }
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grep -q '^listen_addr = 127.0.0.1' "$INI" || { echo "DRIFT listen_addr changed (remote access migration?)"; exit 1; }
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echo "OK pgbouncer on 127.0.0.1:6432, transaction mode"
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;;
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down)
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systemctl disable --now pgbouncer 2>/dev/null || true
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export DEBIAN_FRONTEND=noninteractive
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apt-get purge -y pgbouncer >/dev/null
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rm -rf /etc/pgbouncer "$LOG"
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echo " pgbouncer stopped, purged, config removed"
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;;
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esac
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