ProxySQL monitoring is its own category, and treating it as just another MySQL instance is the first mistake buyers make. ProxySQL exposes its own stats schema on the admin interface at port 6032: stats_mysql_connection_pool, stats_mysql_global, stats_mysql_query_digest, and stats_mysql_commands_counters. Since version 2.1 it also ships a built-in Prometheus endpoint. A tool that only monitors the MySQL servers behind the proxy, or that only replays ProxySQL’s own monitor module checks (connect, ping, read-only, replication lag), leaves you blind to pool exhaustion, query routing, and backend status transitions.
The second mistake is assuming any metrics pipeline will do. Three dimensions decide the outcome:
- Metric depth. Does the tool cover connection pools per hostgroup, query digests, command counters, backend states (ONLINE, SHUNNED, OFFLINE_SOFT, OFFLINE_HARD), query cache, and memory, or just a subset?
- Collection resolution. Pool exhaustion and backend latency spikes develop in seconds. Per-second agents catch them; 15-second agent checks and 60-second scrapes often do not.
- Alerting and cost shape. Do you get working alerts for SHUNNED backends and hostgroups with no ONLINE backends out of the box, and does the bill grow per node, per host, per GB, or per active series?
One ground rule for this page: we do not quote competitor list prices. Pricing pages change, tiers hide behind sales calls, and a stale dollar figure is worse than none. Instead we describe each vendor’s pricing shape, what actually makes the bill grow, and link the official pricing page so you can check current numbers yourself. For hands-on setup detail, our operator runbooks for ProxySQL walk through the stats schema and the collectors below.