At a glance
Connections In Use is the live count of client connections currently held against the MariaDB server, read from the global status counterThreads_connected. It is the numerator behind connection-pool saturation: every active application thread, replication channel, monitoring probe, and admin session counts. Read it next tomax_connectionsto know how much headroom is left before new sessions are refused with “Too many connections”.
| What it counts | The real-time value of Threads_connected: currently open client connections, idle and active alike. |
| Data source | SHOW GLOBAL STATUS LIKE 'Threads_connected', with information_schema.PROCESSLIST for the per-session detail. |
| Why it matters | Connections are capped by max_connections; near the cap, new sessions are refused and the storefront throws connection errors. This is the raw input to the saturation gauge. |
| Currency | connections (count) |
| Time window | RT (real-time, refreshed on each poll) |
| Alert trigger | None on this card. Use Connection Pool Saturation % for the threshold alert. |
| Roles | owner, engineering, operations |
What it tracks
This card surfaces the Connections In Use counter for the selected period, sampled live from the MariaDB server’s global status. The figure isThreads_connected: every open session, whether actively running a query or sitting idle inside an application connection pool, adds one to the total. Background work counts too, so replica I/O threads, mariabackup sessions, and the Vortex IQ monitoring connection all appear in the number. Because connections are capped server-wide by max_connections, this raw count is the foundation for capacity planning: divide it by max_connections and you have the pool-saturation percentage that drives the alerting cards. A healthy instance shows a stable baseline that tracks traffic; a session opened but never closed produces a count that ratchets up over hours and eventually exhausts the cap.
Reconciling against the source
To verify the live count directly on the server, runSHOW GLOBAL STATUS LIKE 'Threads_connected'; and compare against SHOW VARIABLES LIKE 'max_connections';. For the per-session breakdown use SELECT * FROM information_schema.PROCESSLIST;. On managed services (Amazon RDS / Aurora for MariaDB, Azure Database for MariaDB, SkySQL) the same value appears as the DatabaseConnections metric in the provider’s monitoring console; brief differences are timing artefacts between poll intervals.