remove wait calls

Author: dwsupplee

src/Spanner/Session/CacheSessionPool.php

@@ -23,6 +23,7 @@
 use Google\Cloud\Core\Lock\SemaphoreLock;
 use Google\Cloud\Core\SysvTrait;
 use Google\Cloud\Spanner\Database;
+use Grpc\UnaryCall;
 use Psr\Cache\CacheItemPoolInterface;
 
 /**
@@ -118,6 +119,11 @@ class CacheSessionPool implements SessionPoolInterface
      */
     private $database;
 
+    /**
+     * @var UnaryCall[]
+     */
+    private $deleteCalls = [];
+
     /**
      * @var array
      */
@@ -756,19 +762,18 @@ private function validateConfig()
      */
     private function deleteSessions(array $sessions)
     {
-        $calls = [];
+        // gRPC calls appear to cancel when the corresponding UnaryCall object
+        // goes out of scope. Keeping the calls in scope allows time for the
+        // calls to complete at the expense of a small memory footprint.
+        $this->deleteCalls = [];
 
         foreach ($sessions as $session) {
-            $calls[] = $this->database->connection()
+            $this->deleteCalls[] = $this->database->connection()
                 ->deleteSessionAsync([
                     'name' => $session['name'],
                     'database' => $this->database->name()
                 ]);
         }
-
-        foreach ($calls as $call) {
-            $call->wait();
-        }
     }
 
     /**

tests/unit/Spanner/Session/CacheSessionPoolTest.php

@@ -288,33 +288,6 @@ public function downsizeDataProvider()
         ];
     }
 
-    public function testDownsizeFails()
-    {
-        $time = time() + 3600;
-        $pool = new CacheSessionPoolStub($this->getCacheItemPool([
-            'queue' => [
-                [
-                    'name' => 'session0',
-                    'expiration' => $time
-                ],
-                [
-                    'name' => 'session1',
-                    'expiration' => $time
-                ]
-            ],
-            'inUse' => [],
-            'toCreate' => [],
-            'windowStart' => $this->time,
-            'maxInUseSessions' => 1
-        ]));
-        $pool->setDatabase($this->getDatabase());
-        $response = $pool->downsize(100);
-
-        $this->assertEquals(0, $response['deleted']);
-        $this->assertEquals(1, count($response['failed']));
-        $this->assertContainsOnlyInstancesOf(Session::class, $response['failed']);
-    }
-
     /**
      * @dataProvider invalidPercentDownsizeDataProvider
      */