Merge "Simplify logic to prevent writes on replica DB connections"

diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index 3d40417..15e02ad 100644 (file)
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -236,12 +236,6 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
        /** @var TransactionProfiler */
        protected $trxProfiler;
 
-       /**
-        * @var bool Whether writing is allowed on this connection.
-        *      Should be false for connections to replicas.
-        */
-       protected $allowWrite = true;
-
        /**
         * Constructor and database handle and attempt to connect to the DB server
         *
@@ -283,7 +277,6 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
                $this->connLogger = $params['connLogger'];
                $this->queryLogger = $params['queryLogger'];
                $this->errorLogger = $params['errorLogger'];
-               $this->allowWrite = empty( $params['noWrite'] );
 
                // Set initial dummy domain until open() sets the final DB/prefix
                $this->currentDomain = DatabaseDomain::newUnspecified();
@@ -915,13 +908,12 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
                }
 
                if ( $isWrite ) {
-                       if ( !$this->allowWrite ) {
+                       if ( $this->getLBInfo( 'replica' ) === true ) {
                                throw new DBError(
                                        $this,
-                                       'Write operations are not allowed on this database connection!'
+                                       'Write operations are not allowed on replica database connections.'
                                );
                        }
-
                        # In theory, non-persistent writes are allowed in read-only mode, but due to things
                        # like https://bugs.mysql.com/bug.php?id=33669 that might not work anyway...
                        $reason = $this->getReadOnlyReason();

diff --git a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
index b565b3b..86c4335 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
@@ -87,9 +87,6 @@ interface ILoadBalancer {
        /** @var int DB handle should have DBO_TRX disabled and the caller will leave it as such */
        const CONN_TRX_AUTO = 1;
 
-       /** Disable writing for the given connection. Used internally. Do not use with DB_MASTER! */
-       const CONN_NO_WRITE = 2;
-
        /**
         * Construct a manager of IDatabase connection objects
         *

diff --git a/includes/libs/rdbms/loadbalancer/LoadBalancer.php b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
index eb288dd..a9eaa99 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -645,12 +645,6 @@ class LoadBalancer implements ILoadBalancer {
                $oldConnsOpened = $this->connsOpened; // connections open now
 
                if ( $i == self::DB_MASTER ) {
-                       if ( $flags & self::CONN_NO_WRITE ) {
-                               throw new InvalidArgumentException(
-                                       'Cannot set CONN_NO_WRITE flag on master connection!'
-                               );
-                       }
-
                        $i = $this->getWriterIndex();
                } else {
                        # Try to find an available server in any the query groups (in order)
@@ -661,9 +655,6 @@ class LoadBalancer implements ILoadBalancer {
                                        break;
                                }
                        }
-
-                       // Request no-write connection, even if $i == $this->getWriterIndex().
-                       $flags |= self::CONN_NO_WRITE;
                }
 
                # Operation-based index
@@ -680,9 +671,6 @@ class LoadBalancer implements ILoadBalancer {
                                $this->reportConnectionError();
                                return null; // not reached
                        }
-
-                       // Request no-write connection, even if $i == $this->getWriterIndex().
-                       $flags |= self::CONN_NO_WRITE;
                }
 
                # Now we have an explicit index into the servers array
@@ -803,13 +791,6 @@ class LoadBalancer implements ILoadBalancer {
                // a) those are usually set to implicitly use transaction rounds via DBO_TRX
                // b) those must support the use of explicit transaction rounds via beginMasterChanges()
                $autoCommit = ( ( $flags & self::CONN_TRX_AUTO ) == self::CONN_TRX_AUTO );
-               $noWrite = ( ( $flags & self::CONN_NO_WRITE ) == self::CONN_NO_WRITE );
-
-               if ( $noWrite && $i === $this->getWriterIndex() ) {
-                       // We can't disable writes on the master connection!
-                       // TODO: Wrap the master connection, so write operations fail!
-                       $noWrite = false;
-               }
 
                if ( $domain !== false ) {
                        // Connection is to a foreign domain
@@ -826,7 +807,6 @@ class LoadBalancer implements ILoadBalancer {
                                // Open a new connection
                                $server = $this->mServers[$i];
                                $server['serverIndex'] = $i;
-                               $server['noWrite'] = $noWrite;
                                $server['autoCommitOnly'] = $autoCommit;
                                $conn = $this->reallyOpenConnection( $server, false );
                                $host = $this->getServerName( $i );
@@ -883,13 +863,6 @@ class LoadBalancer implements ILoadBalancer {
                $dbName = $domainInstance->getDatabase();
                $prefix = $domainInstance->getTablePrefix();
                $autoCommit = ( ( $flags & self::CONN_TRX_AUTO ) == self::CONN_TRX_AUTO );
-               $noWrite = ( ( $flags & self::CONN_NO_WRITE ) == self::CONN_NO_WRITE );
-
-               if ( $noWrite && $i === $this->getWriterIndex() ) {
-                       // We can't disable writes on the master connection!
-                       // TODO: Wrap the master connection, so write operations fail!
-                       $noWrite = false;
-               }
 
                if ( $autoCommit ) {
                        $connFreeKey = self::KEY_FOREIGN_FREE_NOROUND;
@@ -937,7 +910,6 @@ class LoadBalancer implements ILoadBalancer {
                        $server['foreignPoolRefCount'] = 0;
                        $server['foreign'] = true;
                        $server['autoCommitOnly'] = $autoCommit;
-                       $server['noWrite'] = $noWrite;
                        $conn = $this->reallyOpenConnection( $server, $dbName );
                        if ( !$conn->isOpen() ) {
                                $this->connLogger->warning( __METHOD__ . ": connection error for $i/$domain" );