#170: misc updates after the PR gets merged

CHANGELOG.md

@@ -3,6 +3,7 @@
 Fixed:
 
 * MR swoole/library#169: Fix broken requests when keep-alive is turned on in the FastCGI client. (by @NathanFreeman)
+* MR swoole/library#170: Enhance database pool stability by verifying PDO connection existence while fetching. (by @DevZer0x00)
 * Fix accessing undefined properties in method \Swoole\NameResolver::checkResponse(). ([commit](https://github.com/swoole/library/commit/7a6396e45f4d4517a049584a746285d6501cf71d))
 * Fix the implementation of method `\Swoole\MultibyteStringObject::chunk()`. ([commit](https://github.com/swoole/library/commit/031eba5f6db2ffac66ce1cca6d1d63a213203724))
 * Connection pool in Swoole does not support in-memory or temporary SQLite databases. ([commit](https://github.com/swoole/library/commit/eaf6a43f2fdd403e7d4968fd6f4bd0d1b05e48c3))

src/__init__.php

@@ -24,6 +24,7 @@
  'core/StringObject.php',
  'core/MultibyteStringObject.php',
  'core/Exception/ArrayKeyNotExists.php',
+ 'core/Exception/TimeoutException.php',
  'core/ArrayObject.php',
  'core/ObjectProxy.php',
  'core/Coroutine/WaitGroup.php',

src/core/ConnectionPool.php

@@ -39,6 +39,12 @@ public function fill(): void
  }
  }
 
+ /**
+ * Get a connection from the pool.
+ *
+ * @param float $timeout > 0 means waiting for the specified number of seconds. other means no waiting.
+ * @return mixed|false Returns a connection object from the pool, or false if the pool is full and the timeout is reached.
+ */
  public function get(float $timeout = -1)
  {
  if ($this->pool === null) {

src/core/Database/PDOPool.php

@@ -32,13 +32,19 @@ public function __construct(protected PDOConfig $config, int $size = self::DEFAU
  }, $size, PDOProxy::class);
  }
 
+ /**
+ * Get a PDO connection from the pool. The PDO connection (a PDO object) is wrapped in a PDOProxy object returned.
+ *
+ * @param float $timeout > 0 means waiting for the specified number of seconds. other means no waiting.
+ * @return PDOProxy|false Returns a PDOProxy object from the pool, or false if the pool is full and the timeout is reached.
+ * {@inheritDoc}
+ */
  public function get(float $timeout = -1)
  {
- /* @var \Swoole\Database\PDOProxy|bool $pdo */
+ /* @var \Swoole\Database\PDOProxy|false $pdo */
  $pdo = parent::get($timeout);
-
  if ($pdo === false) {
- throw new TimeoutException();
+ throw new TimeoutException('Failed to get a PDO connection: The pool is at full capacity, yet all connections are currently in use.');
  }
 
  $pdo->reset();

tests/unit/Database/PDOPoolTest.php

@@ -218,11 +218,12 @@ public function testSqlite(): void
  });
  }
 
- public function testTimeoutException()
+ public function testTimeoutException(): void
  {
  self::saveHookFlags();
  self::setHookFlags(SWOOLE_HOOK_ALL);
- run(function () use (&$timeoutOccured) {
+ $failed = false;
+ run(function () use (&$failed) {
  $config = (new PDOConfig())
  ->withHost(MYSQL_SERVER_HOST)
  ->withPort(MYSQL_SERVER_PORT)
@@ -232,24 +233,30 @@ public function testTimeoutException()
  ->withPassword(MYSQL_SERVER_PWD)
  ;
 
- $pool = new PDOPool($config, 1);
- $timeoutOccured = false;
- go(function () use ($pool, &$timeoutOccured) {
+ $pool = new PDOPool($config, 1);
+ $waitGroup = new WaitGroup(2); // A wait group to wait for the next 2 coroutines to finish.
+
+ go(function () use ($pool, $waitGroup) {
+ $pool->get()->exec('SELECT SLEEP(1)'); // Hold the connection for 1 second before putting it back into the pool.
+ $waitGroup->done();
+ });
+
+ go(function () use ($pool, $waitGroup, &$failed) {
+ Coroutine::sleep(0.1); // Sleep for 0.1 second to ensure the 1st connection is in use by the 1st coroutine.
  try {
- $pool->get(2);
+ $pool->get(0.5); // Try to get a 2nd connection from the pool within 0.5 seconds.
  } catch (TimeoutException) {
- $timeoutOccured = true;
+ $failed = true;
+ } finally {
+ $waitGroup->done();
  }
  });
 
- go(function () use ($pool) {
- $pdo = $pool->get(1);
- $pdo->exec('SELECT SLEEP(2)');
- });
- });
-
- $this->assertTrue($timeoutOccured);
+ $waitGroup->wait();
+ $pool->close();
+ self::restoreHookFlags();
 
- self::restoreHookFlags();
+ self::assertTrue($failed, 'Failed to get a 2nd connection from the pool within 0.5 seconds');
+ });
  }
 }