Addshore has uploaded a new change for review.
https://gerrit.wikimedia.org/r/322644
Change subject: Add DB ConnectionManagers
......................................................................
Add DB ConnectionManagers
This moves and refactors the ConsistentReadConnectionManager
from Wikibase into the core rdbms lib.
The refactoring also creates a generic ConnectionManager.
This relates to Iff20a22f9f2bc7ceefd6defc0ed9a494a6fe62c0
which introduced a DB factory / connection manager in
an extension revealing the need for this in multiple places.
Change-Id: I0c58e15aed5bed88323d18cb95e5008f8d3381c5
---
M autoload.php
A includes/libs/rdbms/connectionmanager/ConnectionManager.php
A includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManager.php
A tests/phpunit/includes/libs/rdbms/connectionmanager/ConnectionManagerTest.php
A
tests/phpunit/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManagerTest.php
5 files changed, 439 insertions(+), 0 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/44/322644/1
diff --git a/autoload.php b/autoload.php
index 30ef985..9d67be7 100644
--- a/autoload.php
+++ b/autoload.php
@@ -592,6 +592,8 @@
'IEUrlExtension' => __DIR__ . '/includes/libs/IEUrlExtension.php',
'IExpiringStore' => __DIR__ .
'/includes/libs/objectcache/IExpiringStore.php',
'IJobSpecification' => __DIR__ .
'/includes/jobqueue/JobSpecification.php',
+ 'ConnectionManager' => __DIR__ .
'/includes/libs/rdbms/connectionmanager/ConnectionManager.php',
+ 'ConsistentReadConnectionManager' => __DIR__ .
'/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManager.php',
'ILBFactory' => __DIR__ .
'/includes/libs/rdbms/lbfactory/ILBFactory.php',
'ILoadBalancer' => __DIR__ .
'/includes/libs/rdbms/loadbalancer/ILoadBalancer.php',
'ILoadMonitor' => __DIR__ .
'/includes/libs/rdbms/loadmonitor/ILoadMonitor.php',
diff --git a/includes/libs/rdbms/connectionmanager/ConnectionManager.php
b/includes/libs/rdbms/connectionmanager/ConnectionManager.php
new file mode 100644
index 0000000..1b0eb76
--- /dev/null
+++ b/includes/libs/rdbms/connectionmanager/ConnectionManager.php
@@ -0,0 +1,126 @@
+<?php
+
+/**
+ * Database connection manager.
+ *
+ * This manages access to master and slave databases.
+ *
+ * @since 1.29
+ *
+ * @license GPL-2.0+
+ * @author Addshore
+ */
+class ConnectionManager {
+
+ /**
+ * @var LoadBalancer
+ */
+ private $loadBalancer;
+
+ /**
+ * The symbolic name of the target database, or false for the local
wiki's database.
+ *
+ * @var string|false
+ */
+ private $dbName;
+
+ /**
+ * @var int Db to use for write connections (can be overridden in
subclasses)
+ */
+ protected $writeDbIndex = DB_MASTER;
+
+ /**
+ * @var int Db to use for read connections (can be overridden in
subclasses)
+ */
+ protected $readDbIndex = DB_REPLICA;
+
+ /**
+ * @param LoadBalancer $loadBalancer
+ * @param string|bool $dbName Optional, defaults to current wiki.
+ * This follows the convention for database names used by
$loadBalancer.
+ *
+ * @throws InvalidArgumentException
+ */
+ public function __construct( LoadBalancer $loadBalancer, $dbName =
false ) {
+ if ( !is_string( $dbName ) && $dbName !== false ) {
+ throw new InvalidArgumentException( '$dbName must be a
string, or false.' );
+ }
+
+ $this->loadBalancer = $loadBalancer;
+ $this->dbName = $dbName;
+ }
+
+ /**
+ * @param int $i
+ *
+ * @return Database
+ */
+ private function getConnection( $i ) {
+ return $this->loadBalancer->getConnection( $i, [],
$this->dbName );
+ }
+
+ /**
+ * @param int $i
+ *
+ * @return DBConnRef
+ */
+ private function getConnectionRef( $i ) {
+ return $this->loadBalancer->getConnectionRef( $i, [],
$this->dbName );
+ }
+
+ /**
+ * Returns a connection to the master DB, for updating. The connection
should later be released
+ * by calling releaseConnection().
+ *
+ * @since 1.29
+ *
+ * @return Database
+ */
+ public function getWriteConnection() {
+ return $this->getConnection( $this->writeDbIndex );
+ }
+
+ /**
+ * Returns a database connection for reading. The connection should
later be released by
+ * calling releaseConnection().
+ *
+ * @since 1.29
+ *
+ * @return Database
+ */
+ public function getReadConnection() {
+ return $this->getConnection( $this->readDbIndex );
+ }
+
+ /**
+ * @since 1.29
+ *
+ * @param IDatabase $db
+ */
+ public function releaseConnection( IDatabase $db ) {
+ $this->loadBalancer->reuseConnection( $db );
+ }
+
+ /**
+ * Returns a connection ref to the master DB, for updating.
+ *
+ * @since 1.29
+ *
+ * @return DBConnRef
+ */
+ public function getWriteConnectionRef() {
+ return $this->getConnectionRef( $this->writeDbIndex );
+ }
+
+ /**
+ * Returns a database connection ref for reading.
+ *
+ * @since 1.29
+ *
+ * @return DBConnRef
+ */
+ public function getReadConnectionRef() {
+ return $this->getConnectionRef( $this->readDbIndex );
+ }
+
+}
diff --git
a/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManager.php
b/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManager.php
new file mode 100644
index 0000000..1145c5f
--- /dev/null
+++ b/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManager.php
@@ -0,0 +1,82 @@
+<?php
+
+/**
+ * Database connection manager.
+ *
+ * This manages access to master and slave databases. It also manages state
that indicates whether
+ * the slave databases are possibly outdated after a write operation, and thus
the master database
+ * should be used for subsequent read operations.
+ *
+ * @note: Services that access overlapping sets of database tables, or
interact with logically
+ * related sets of data in the database, should share a
ConsistentReadConnectionManager.
+ * Services accessing unrelated sets of information may prefer to not share a
+ * ConsistentReadConnectionManager, so they can still perform read operations
against slave
+ * databases after a (unrelated, per the assumption) write operation to the
master database.
+ * Generally, sharing a ConsistentReadConnectionManager improves consistency
(by avoiding race
+ * conditions due to replication lag), but can reduce performance (by
directing more read
+ * operations to the master database server).
+ *
+ * @since 1.29
+ *
+ * @license GPL-2.0+
+ * @author Daniel Kinzler
+ */
+class ConsistentReadConnectionManager extends ConnectionManager {
+
+ /**
+ * Forces all future calls to getReadConnection() to return a
connection to the master DB.
+ * Use this before performing read operations that are critical for a
future update.
+ * Calling beginAtomicSection() implies a call to forceMaster().
+ *
+ * @since 1.29
+ */
+ public function forceMaster() {
+ $this->readDbIndex = $this->writeDbIndex;
+ }
+
+ /**
+ * Begins an atomic section and returns a database connection to the
master DB, for updating.
+ *
+ * @since 1.29
+ *
+ * @note: This causes all future calls to getReadConnection() to return
a connection
+ * to the master DB, even after commitAtomicSection() or
rollbackAtomicSection() have
+ * been called.
+ *
+ * @param string $fname
+ *
+ * @return Database
+ */
+ public function beginAtomicSection( $fname ) {
+ // Once we have written to master, do not read from slave.
+ $this->forceMaster();
+
+ $db = $this->getWriteConnection();
+ $db->startAtomic( $fname );
+ return $db;
+ }
+
+ /**
+ * @since 1.29
+ *
+ * @param IDatabase $db
+ * @param string $fname
+ */
+ public function commitAtomicSection( IDatabase $db, $fname ) {
+ $db->endAtomic( $fname );
+ $this->releaseConnection( $db );
+ }
+
+ /**
+ * @since 1.29
+ *
+ * @param IDatabase $db
+ * @param string $fname
+ */
+ public function rollbackAtomicSection( IDatabase $db, $fname ) {
+ // FIXME: there does not seem to be a clean way to roll back an
atomic section?!
+ $db->rollback( $fname, 'flush' );
+ $this->releaseConnection( $db );
+ }
+
+}
diff --git
a/tests/phpunit/includes/libs/rdbms/connectionmanager/ConnectionManagerTest.php
b/tests/phpunit/includes/libs/rdbms/connectionmanager/ConnectionManagerTest.php
new file mode 100644
index 0000000..4186854
--- /dev/null
+++
b/tests/phpunit/includes/libs/rdbms/connectionmanager/ConnectionManagerTest.php
@@ -0,0 +1,72 @@
+<?php
+
+/**
+ * @covers ConnectionManager
+ *
+ * @license GPL-2.0+
+ * @author Daniel Kinzler
+ */
+class ConnectionManagerTest extends \PHPUnit_Framework_TestCase {
+
+ /**
+ * @return IDatabase|PHPUnit_Framework_MockObject_MockObject
+ */
+ private function getIDatabaseMock() {
+ return $this->getMock( IDatabase::class );
+ }
+
+ /**
+ * @return LoadBalancer|PHPUnit_Framework_MockObject_MockObject
+ */
+ private function getLoadBalancerMock() {
+ $lb = $this->getMockBuilder( LoadBalancer::class )
+ ->disableOriginalConstructor()
+ ->getMock();
+
+ return $lb;
+ }
+
+ public function testGetReadConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_SLAVE )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $actual = $manager->getReadConnection();
+
+ $this->assertSame( $database, $actual );
+ }
+
+ public function testGetWriteConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_MASTER )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $actual = $manager->getWriteConnection();
+
+ $this->assertSame( $database, $actual );
+ }
+
+ public function testReleaseConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'reuseConnection' )
+ ->with( $database )
+ ->will( $this->returnValue( null ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->releaseConnection( $database );
+ }
+
+}
diff --git
a/tests/phpunit/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManagerTest.php
b/tests/phpunit/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManagerTest.php
new file mode 100644
index 0000000..f8dd86d
--- /dev/null
+++
b/tests/phpunit/includes/libs/rdbms/connectionmanager/ConsistentReadConnectionManagerTest.php
@@ -0,0 +1,157 @@
+<?php
+
+/**
+ * @covers ConsistentReadConnectionManager
+ *
+ * @license GPL-2.0+
+ * @author Daniel Kinzler
+ */
+class ConsistentReadConnectionManagerTest extends \PHPUnit_Framework_TestCase {
+
+ /**
+ * @return IDatabase|PHPUnit_Framework_MockObject_MockObject
+ */
+ private function getIDatabaseMock() {
+ return $this->getMock( IDatabase::class );
+ }
+
+ /**
+ * @return LoadBalancer|PHPUnit_Framework_MockObject_MockObject
+ */
+ private function getLoadBalancerMock() {
+ $lb = $this->getMockBuilder( LoadBalancer::class )
+ ->disableOriginalConstructor()
+ ->getMock();
+
+ return $lb;
+ }
+
+ public function testGetReadConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_SLAVE )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $actual = $manager->getReadConnection();
+
+ $this->assertSame( $database, $actual );
+ }
+
+ public function testGetReadConnectionReturnsWriteDbOnForceMatser() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_MASTER )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->forceMaster();
+ $actual = $manager->getReadConnection();
+
+ $this->assertSame( $database, $actual );
+ }
+
+ public function testGetWriteConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_MASTER )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $actual = $manager->getWriteConnection();
+
+ $this->assertSame( $database, $actual );
+ }
+
+ public function testForceMaster() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'getConnection' )
+ ->with( DB_MASTER )
+ ->will( $this->returnValue( $database ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->forceMaster();
+ $manager->getReadConnection();
+ }
+
+ public function testReleaseConnection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'reuseConnection' )
+ ->with( $database )
+ ->will( $this->returnValue( null ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->releaseConnection( $database );
+ }
+
+ public function testBeginAtomicSection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->exactly( 2 ) )
+ ->method( 'getConnection' )
+ ->with( DB_MASTER )
+ ->will( $this->returnValue( $database ) );
+
+ $database->expects( $this->once() )
+ ->method( 'startAtomic' )
+ ->will( $this->returnValue( null ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->beginAtomicSection( 'TEST' );
+
+ // Should also ask for a DB_MASTER connection.
+ // This is asserted by the $lb mock.
+ $manager->getReadConnection();
+ }
+
+ public function testCommitAtomicSection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'reuseConnection' )
+ ->with( $database )
+ ->will( $this->returnValue( null ) );
+
+ $database->expects( $this->once() )
+ ->method( 'endAtomic' )
+ ->will( $this->returnValue( null ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->commitAtomicSection( $database, 'TEST' );
+ }
+
+ public function testRollbackAtomicSection() {
+ $database = $this->getIDatabaseMock();
+ $lb = $this->getLoadBalancerMock();
+
+ $lb->expects( $this->once() )
+ ->method( 'reuseConnection' )
+ ->with( $database )
+ ->will( $this->returnValue( null ) );
+
+ $database->expects( $this->once() )
+ ->method( 'rollback' )
+ ->will( $this->returnValue( null ) );
+
+ $manager = new ConsistentReadConnectionManager( $lb );
+ $manager->rollbackAtomicSection( $database, 'TEST' );
+ }
+
+}
--
To view, visit https://gerrit.wikimedia.org/r/322644
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I0c58e15aed5bed88323d18cb95e5008f8d3381c5
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Addshore <[email protected]>
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