Connection pooling.

also: connection pool · connection pools · keep-alive · HTTP keep-alive

Keeping a set of open connections and reusing them across requests, instead of paying a new handshake each time.

the two-minute refresher

Keep-alive reuses one HTTP connection for several requests; a pool keeps many ready at the application level.
It saves TCP and TLS round trips and avoids ephemeral port exhaustion.
Size pools on purpose: too small queues requests, too big overwhelms the database.
A pool per dependency doubles as a bulkhead: one slow service can't take every connection.

also: connection pool · connection pools · keep-alive · HTTP keep-alive

Keeping a set of open connections and reusing them across requests, instead of paying a new handshake each time.

Keep-alive reuses one HTTP connection for several requests; a pool keeps many ready at the application level.
It saves TCP and TLS round trips and avoids ephemeral port exhaustion.
Size pools on purpose: too small queues requests, too big overwhelms the database.
A pool per dependency doubles as a bulkhead: one slow service can't take every connection.