From 22508bec75fb05546520398ac0a195c7c79ef87e Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 23 Feb 2015 16:32:00 -0800
Subject: [PATCH] Allow configuring the transaction locking mode for SQLite

Bug: T89180
Change-Id: Ib18347299ea78f9b31e56313b2acf749f693cddb
---
 includes/db/DatabaseSqlite.php | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/includes/db/DatabaseSqlite.php b/includes/db/DatabaseSqlite.php
index 7b04716f43..0b51972ee1 100644
--- a/includes/db/DatabaseSqlite.php
+++ b/includes/db/DatabaseSqlite.php
@@ -32,6 +32,9 @@ class DatabaseSqlite extends DatabaseBase {
 	/** @var string File name for SQLite database file */
 	public $mDatabaseFile;
 
+	/** @var string Transaction mode */
+	protected $trxMode;
+
 	/** @var int The number of rows affected as an integer */
 	protected $mAffectedRows;
 
@@ -44,6 +47,11 @@ class DatabaseSqlite extends DatabaseBase {
 	/** @var FSLockManager (hopefully on the same server as the DB) */
 	protected $lockMgr;
 
+	/**
+	 * Additional params include:
+	 *   - trxMode : one of (deferred, immediate, exclusive)
+	 * @param array $p
+	 */
 	function __construct( array $p ) {
 		global $wgSharedDB, $wgSQLiteDataDir;
 
@@ -58,6 +66,12 @@ class DatabaseSqlite extends DatabaseBase {
 			}
 		}
 
+		$this->trxMode = isset( $p['trxMode'] ) ? strtoupper( $p['trxMode'] ) : null;
+		if ( $this->trxMode && !in_array( $this->trxMode, array( 'IMMEDIATE', 'EXCLUSIVE' ) ) ) {
+			$this->trxMode = null;
+			wfWarn( "Invalid SQLite transaction mode provided." );
+		}
+
 		$this->lockMgr = new FSLockManager( array( 'lockDirectory' => "$wgSQLiteDataDir/locks" ) );
 	}
 
@@ -697,6 +711,15 @@ class DatabaseSqlite extends DatabaseBase {
 		return false;
 	}
 
+	protected function doBegin( $fname = '' ) {
+		if ( $this->trxMode ) {
+			$this->query( "BEGIN {$this->trxMode}", $fname );
+		} else {
+			$this->query( 'BEGIN', $fname );
+		}
+		$this->mTrxLevel = 1;
+	}
+
 	/**
 	 * @param string $s
 	 * @return string
-- 
2.20.1