From 0b530983c2a01ea9005c5fbf9c909273b357d663 Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Wed, 3 Apr 2019 14:02:26 -0500
Subject: [PATCH] Remove statement pool caching

---
 composer.json             |   3 +-
 src/Pool.php              | 104 --------------------------------------
 test/AbstractPoolTest.php |  27 ----------
 test/PgSqlPoolTest.php    |   2 +-
 test/PqPoolTest.php       |   2 +-
 5 files changed, 3 insertions(+), 135 deletions(-)
 delete mode 100644 test/AbstractPoolTest.php

diff --git a/composer.json b/composer.json
index 76b02c6..9a0fa37 100644
--- a/composer.json
+++ b/composer.json
@@ -22,8 +22,7 @@
         "php": "^7.0",
         "amphp/amp": "^2",
         "amphp/sql": "^1",
-        "amphp/sql-common": "^1",
-        "cash/lrucache": "^1"
+        "amphp/sql-common": "^1"
     },
     "require-dev": {
         "amphp/phpunit-util": "^1",
diff --git a/src/Pool.php b/src/Pool.php
index e05ff66..b468c79 100644
--- a/src/Pool.php
+++ b/src/Pool.php
@@ -3,7 +3,6 @@
 namespace Amp\Postgres;
 
 use Amp\Coroutine;
-use Amp\Loop;
 use Amp\Promise;
 use Amp\Sql\Common\ConnectionPool;
 use Amp\Sql\Common\StatementPool as SqlStatementPool;
@@ -13,7 +12,6 @@ use Amp\Sql\Pool as SqlPool;
 use Amp\Sql\ResultSet as SqlResultSet;
 use Amp\Sql\Statement as SqlStatement;
 use Amp\Sql\Transaction as SqlTransaction;
-use cash\LRUCache;
 use function Amp\call;
 
 final class Pool extends ConnectionPool implements Link
@@ -27,12 +25,6 @@ final class Pool extends ConnectionPool implements Link
     /** @var bool */
     private $resetConnections;
 
-    /** @var string */
-    private $statementWatcher;
-
-    /** @var LRUCache|\IteratorAggregate Least-recently-used cache of StatementPool objects. */
-    private $statements;
-
     /**
      * @param ConnectionConfig $config
      * @param int              $maxConnections
@@ -50,45 +42,6 @@ final class Pool extends ConnectionPool implements Link
         parent::__construct($config, $maxConnections, $idleTimeout, $connector);
 
         $this->resetConnections = $resetConnections;
-
-        $this->statements = $statements = new class($maxConnections) extends LRUCache implements \IteratorAggregate {
-            public function getIterator(): \Iterator
-            {
-                yield from $this->data;
-            }
-        };
-
-        $this->statementWatcher = Loop::repeat(1000, static function () use (&$idleTimeout, $statements) {
-            $now = \time();
-
-            foreach ($statements as $sql => $statement) {
-                if ($statement instanceof Promise) {
-                    continue;
-                }
-
-                \assert($statement instanceof StatementPool);
-
-                if ($statement->getLastUsedAt() + $idleTimeout > $now) {
-                    return;
-                }
-
-                $statements->remove($sql);
-            }
-        });
-
-        Loop::unreference($this->statementWatcher);
-    }
-
-    public function __destruct()
-    {
-        parent::__destruct();
-        Loop::cancel($this->statementWatcher);
-    }
-
-    public function close()
-    {
-        parent::close();
-        $this->statements->clear();
     }
 
     /**
@@ -133,63 +86,6 @@ final class Pool extends ConnectionPool implements Link
         return $connection;
     }
 
-    /**
-     * {@inheritdoc}
-     *
-     * Caches prepared statements for reuse.
-     */
-    public function prepare(string $sql): Promise
-    {
-        if (!$this->isAlive()) {
-            throw new \Error("The pool has been closed");
-        }
-
-        return call(function () use ($sql) {
-            $name = Handle::STATEMENT_NAME_PREFIX . \sha1($sql);
-
-            if ($this->statements->containsKey($name)) {
-                $statement = $this->statements->get($name);
-
-                if ($statement instanceof Promise) {
-                    $statement = yield $statement; // Wait for prior request to resolve.
-                }
-
-                \assert($statement instanceof StatementPool);
-
-                if ($statement->isAlive()) {
-                    return $statement;
-                }
-            }
-
-            $promise = parent::prepare($sql);
-            $this->statements->put($name, $promise); // Insert promise into queue so subsequent requests get promise.
-
-            try {
-                $statement = yield $promise;
-                \assert($statement instanceof StatementPool);
-            } catch (\Throwable $exception) {
-                $this->statements->remove($name);
-                throw $exception;
-            }
-
-            $this->statements->put($name, $statement); // Replace promise in queue with statement object.
-
-            return $statement;
-        });
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function execute(string $sql, array $params = []): Promise
-    {
-        return call(function () use ($sql, $params) {
-            $statement = yield $this->prepare($sql);
-            \assert($statement instanceof SqlStatement);
-            return yield $statement->execute($params);
-        });
-    }
-
     /**
      * {@inheritdoc}
      */
diff --git a/test/AbstractPoolTest.php b/test/AbstractPoolTest.php
deleted file mode 100644
index 0de720b..0000000
--- a/test/AbstractPoolTest.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-namespace Amp\Postgres\Test;
-
-use Amp\Loop;
-use Amp\Postgres\StatementPool;
-
-abstract class AbstractPoolTest extends AbstractLinkTest
-{
-    public function testPrepareSameQueryReturnsSameStatementPool()
-    {
-        Loop::run(function () {
-            $sql = "SELECT * FROM test WHERE domain=\$1";
-
-            /** @var StatementPool $statement1 */
-            $statement1 = yield $this->connection->prepare($sql);
-
-            /** @var StatementPool $statement2 */
-            $statement2 = yield $this->connection->prepare($sql);
-
-            $this->assertInstanceOf(StatementPool::class, $statement1);
-            $this->assertInstanceOf(StatementPool::class, $statement2);
-
-            $this->assertSame($statement1, $statement2);
-        });
-    }
-}
diff --git a/test/PgSqlPoolTest.php b/test/PgSqlPoolTest.php
index d84d83a..22935c0 100644
--- a/test/PgSqlPoolTest.php
+++ b/test/PgSqlPoolTest.php
@@ -14,7 +14,7 @@ use Amp\Success;
 /**
  * @requires extension pgsql
  */
-class PgSqlPoolTest extends AbstractPoolTest
+class PgSqlPoolTest extends AbstractLinkTest
 {
     const POOL_SIZE = 3;
 
diff --git a/test/PqPoolTest.php b/test/PqPoolTest.php
index 80fcdaa..d9243e9 100644
--- a/test/PqPoolTest.php
+++ b/test/PqPoolTest.php
@@ -13,7 +13,7 @@ use Amp\Success;
 /**
  * @requires extension pq
  */
-class PqPoolTest extends AbstractPoolTest
+class PqPoolTest extends AbstractLinkTest
 {
     const POOL_SIZE = 3;