heliosdb-proxy 0.4.2

HeliosProxy - Intelligent connection router and failover manager for HeliosDB and PostgreSQL
Documentation 
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# HeliosProxy Configuration — Failover Demo with Transaction Replay
#
# Key differences from the basic cluster example:
#   - TR mode set to "transaction" for full replay capability
#   - Aggressive health check intervals (2s) to detect failure quickly
#   - Low failure threshold (2) so failover triggers after ~4 seconds
#   - Write timeout of 15s to allow time for re-routing during failover

listen_address = "0.0.0.0:6432"
admin_address  = "0.0.0.0:9090"

# ── Transaction Replay (TR) ─────────────────────────────────────────
# Modes:
#   "none"        — no replay
#   "session"     — re-establish session state (SET commands, search_path)
#   "select"      — replay read-only queries on new backend
#   "transaction" — full replay of in-flight transactions after failover
tr_enabled = true
tr_mode    = "transaction"

# How long to wait for writes to succeed during a failover window
write_timeout_secs = 15

# ── Connection Pool ──────────────────────────────────────────────────
[pool]
min_connections      = 2
max_connections      = 30
idle_timeout_secs    = 300
max_lifetime_secs    = 1800
acquire_timeout_secs = 10
test_on_acquire      = true

# ── Pool Mode ────────────────────────────────────────────────────────
[pool_mode]
mode                    = "transaction"
max_pool_size           = 30
min_idle                = 2
idle_timeout_secs       = 300
max_lifetime_secs       = 1800
acquire_timeout_secs    = 5
reset_query             = "DISCARD ALL"
prepared_statement_mode = "track"

# ── Load Balancer ────────────────────────────────────────────────────
[load_balancer]
read_strategy        = "least_connections"
read_write_split     = true
latency_threshold_ms = 50

# ── Health Checks (aggressive for demo) ──────────────────────────────
# - Check every 2 seconds
# - Timeout after 2 seconds
# - Mark unhealthy after 2 consecutive failures (~4s detection)
# - Mark healthy again after 2 consecutive successes
[health]
check_interval_secs = 2
check_timeout_secs  = 2
failure_threshold   = 2
success_threshold   = 2
check_query         = "SELECT 1"

# ── Backend Nodes ────────────────────────────────────────────────────

[[nodes]]
host    = "pg-primary"
port    = 5432
role    = "primary"
weight  = 100
enabled = true
name    = "primary"

[[nodes]]
host    = "pg-standby1"
port    = 5432
role    = "standby"
weight  = 100
enabled = true
name    = "standby-1"

[[nodes]]
host    = "pg-standby2"
port    = 5432
role    = "standby"
weight  = 100
enabled = true
name    = "standby-2"