CSHARP-5711: Avoid clearing the connection pool when the server connection rate limiter triggers

Author: sanych-sun

specifications/connection-monitoring-and-pooling/tests/cmap-format/README.rst

@@ -23,6 +23,7 @@
  }
  },
  "poolOptions": {
+ "maxConnecting": 2,
  "maxPoolSize": 10,
  "waitQueueTimeoutMS": 5000
  },
@@ -72,9 +73,8 @@
  "connection": "conn0"
  },
  {
- "name": "waitForEvent",
- "event": "ConnectionCheckedOut",
- "count": 4
+ "name": "wait",
+ "ms": 100
  }
  ],
  "events": [
@@ -104,14 +104,6 @@
  "type": "ConnectionCheckedOut",
  "connectionId": 1,
  "address": 42
- },
- {
- "type": "ConnectionCheckedOut",
- "address": 42
- },
- {
- "type": "ConnectionCheckedOut",
- "address": 42
  }
  ],
  "ignore": [

specifications/connection-monitoring-and-pooling/tests/cmap-format/pool-checkout-returned-connection-maxConnecting.json

@@ -15,6 +15,7 @@ failPoint:
  blockConnection: true
  blockTimeMS: 750
 poolOptions:
+ maxConnecting: 2
  maxPoolSize: 10
  waitQueueTimeoutMS: 5000
 operations:
@@ -45,14 +46,13 @@ operations:
  count: 4
  - name: wait
  ms: 100
- # check original connection back in, so the thread that isn't
- # currently establishing will become unblocked. Then wait for
- # all threads to complete.
+ # Check original connection back in, so one of the waiting threads can check
+ # out the idle connection before the two new connections are ready.
  - name: checkIn
  connection: conn0
- - name: waitForEvent
-  event: ConnectionCheckedOut
- count: 4
+ # Wait for 100ms to let one of the blocked checkOut operations complete.
+ - name: wait
+ ms: 100
 events:
  # main thread checking out a Connection and holding it
  - type: ConnectionCreated
@@ -69,15 +69,13 @@ events:
  - type: ConnectionCheckedIn
  connectionId: 1
  address: 42
- # remaining thread checking out the returned Connection
+ # Another thread checks out the returned Connection before the two new
+ # connections are checked out.
  - type: ConnectionCheckedOut
  connectionId: 1
  address: 42
- # first two threads finishing Connection establishment
- - type: ConnectionCheckedOut
- address: 42
- - type: ConnectionCheckedOut
- address: 42
+ # Events after this can come in different orders but still be valid.
+ # See DRIVERS-2223 for details.
 ignore:
  - ConnectionPoolReady
  - ConnectionClosed