From 4535a81446937fcdea7cce218d65d8ce28459793 Mon Sep 17 00:00:00 2001
From: catch <catch@35733.no-reply.drupal.org>
Date: Thu, 14 Mar 2013 10:36:35 +0000
Subject: [PATCH] Issue #1839998 by wiifm, mcm.guaba, Josh Waihi: Fixed
TruncateQuery implemented as 'DELETE FROM' in MySQL and SQLite, but not
PostgreSQL, causing nefarious table locking.
---
.../Core/Database/Driver/mysql/Truncate.php | 16 +---------------
.../Core/Database/Driver/sqlite/Truncate.php | 2 +-
core/lib/Drupal/Core/Database/Query/Truncate.php | 12 +++++++++++-
3 files changed, 13 insertions(+), 17 deletions(-)
diff --git a/core/lib/Drupal/Core/Database/Driver/mysql/Truncate.php b/core/lib/Drupal/Core/Database/Driver/mysql/Truncate.php
index d0adfad10f2b..c7d7a36ca0ee 100644
--- a/core/lib/Drupal/Core/Database/Driver/mysql/Truncate.php
+++ b/core/lib/Drupal/Core/Database/Driver/mysql/Truncate.php
@@ -9,18 +9,4 @@
use Drupal\Core\Database\Query\Truncate as QueryTruncate;
-class Truncate extends QueryTruncate {
- public function __toString() {
- // TRUNCATE is actually a DDL statement on MySQL, and DDL statements are
- // not transactional, and result in an implicit COMMIT. When we are in a
- // transaction, fallback to the slower, but transactional, DELETE.
- if ($this->connection->inTransaction()) {
- // Create a comment string to prepend to the query.
- $comments = $this->connection->makeComment($this->comments);
- return $comments . 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '}';
- }
- else {
- return parent::__toString();
- }
- }
-}
+class Truncate extends QueryTruncate { }
diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php
index bc635404447f..d06d27ebb705 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php
@@ -22,4 +22,4 @@ public function __toString() {
return $comments . 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '} ';
}
-}
\ No newline at end of file
+}
diff --git a/core/lib/Drupal/Core/Database/Query/Truncate.php b/core/lib/Drupal/Core/Database/Query/Truncate.php
index 263acf50ab60..ea67dad60a34 100644
--- a/core/lib/Drupal/Core/Database/Query/Truncate.php
+++ b/core/lib/Drupal/Core/Database/Query/Truncate.php
@@ -73,6 +73,16 @@ public function __toString() {
// Create a sanitized comment string to prepend to the query.
$comments = $this->connection->makeComment($this->comments);
- return $comments . 'TRUNCATE {' . $this->connection->escapeTable($this->table) . '} ';
+ // In most cases, TRUNCATE is not a transaction safe statement as it is a
+ // DDL statement which results in an implicit COMMIT. When we are in a
+ // transaction, fallback to the slower, but transactional, DELETE.
+ // PostgreSQL also locks the entire table for a TRUNCATE strongly reducing
+ // the concurrency with other transactions.
+ if ($this->connection->inTransaction()) {
+ return $comments . 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '}';
+ }
+ else {
+ return $comments . 'TRUNCATE {' . $this->connection->escapeTable($this->table) . '} ';
+ }
}
}
--
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