diff --git a/includes/Rest/Handler.php b/includes/Rest/Handler.php
index e3ba8117ba4..0437ef881ac 100644
--- a/includes/Rest/Handler.php
+++ b/includes/Rest/Handler.php
@@ -385,8 +385,8 @@ abstract class Handler {
 	 * the database.
 	 *
 	 * This should return true for routes that may require synchronous database writes.
-	 * Modules that do not need such writes should also not rely on master database access,
-	 * since only read queries are needed and each master DB is a single point of failure.
+	 * Modules that do not need such writes should also not rely on primary database access,
+	 * since only read queries are needed and each primary DB is a single point of failure.
 	 *
 	 * @stable to override
 	 *
diff --git a/includes/Revision/RevisionRenderer.php b/includes/Revision/RevisionRenderer.php
index c23de8808f8..e928cb6324a 100644
--- a/includes/Revision/RevisionRenderer.php
+++ b/includes/Revision/RevisionRenderer.php
@@ -124,9 +124,9 @@ class RevisionRenderer {
 			);
 		}
 
-		$useMaster = $hints['use-master'] ?? false;
+		$usePrimary = $hints['use-master'] ?? false;
 
-		$dbIndex = $useMaster
+		$dbIndex = $usePrimary
 			? DB_PRIMARY // use latest values
 			: DB_REPLICA; // T154554
 
diff --git a/includes/Revision/RevisionStore.php b/includes/Revision/RevisionStore.php
index 0dc2829ca36..bc6b942f632 100644
--- a/includes/Revision/RevisionStore.php
+++ b/includes/Revision/RevisionStore.php
@@ -1376,7 +1376,7 @@ class RevisionStore
 		);
 
 		if ( !$res->numRows() && !( $queryFlags & self::READ_LATEST ) ) {
-			// If we found no slots, try looking on the master database (T212428, T252156)
+			// If we found no slots, try looking on the primary database (T212428, T252156)
 			$this->logger->info(
 				__METHOD__ . ' falling back to READ_LATEST.',
 				[
@@ -1723,7 +1723,7 @@ class RevisionStore
 						[ 'rev_id' => intval( $revId ) ]
 					);
 					if ( !$row && !( $queryFlags & self::READ_LATEST ) ) {
-						// If we found no slots, try looking on the master database (T259738)
+						// If we found no slots, try looking on the primary database (T259738)
 						$this->logger->info(
 							 'RevisionStoreCacheRecord refresh callback falling back to READ_LATEST.',
 							[
@@ -2226,7 +2226,7 @@ class RevisionStore
 	 *
 	 * This method should be used if we are pretty sure the revision exists.
 	 * Unless $flags has READ_LATEST set, this method will first try to find the revision
-	 * on a replica before hitting the master database.
+	 * on a replica before hitting the primary database.
 	 *
 	 * MCR migration note: this corresponded to Revision::newFromConds
 	 *
diff --git a/includes/Storage/NameTableStore.php b/includes/Storage/NameTableStore.php
index b7bc5d11d97..e588c6f8578 100644
--- a/includes/Storage/NameTableStore.php
+++ b/includes/Storage/NameTableStore.php
@@ -212,7 +212,7 @@ class NameTableStore {
 	}
 
 	/**
-	 * Reloads the name table from the master database, and purges the WAN cache entry.
+	 * Reloads the name table from the primary database, and purges the WAN cache entry.
 	 *
 	 * @note This should only be called in situations where the local cache has been detected
 	 * to be out of sync with the database. There should be no reason to call this method
@@ -294,12 +294,12 @@ class NameTableStore {
 					// Use the old value
 					return $oldValue;
 				}
-				// Regenerate from replica DB, and master DB if needed
+				// Regenerate from replica DB, and primary DB if needed
 				foreach ( [ DB_REPLICA, DB_PRIMARY ] as $source ) {
-					// Log a fallback to master
+					// Log a fallback to primary
 					if ( $source === DB_PRIMARY ) {
 						$this->logger->info(
-							$fname . ' falling back to master select from ' .
+							$fname . ' falling back to primary select from ' .
 							$this->table . ' with id ' . $id
 						);
 					}
diff --git a/includes/Storage/PageEditStash.php b/includes/Storage/PageEditStash.php
index 2bd4007e667..026283de9e0 100644
--- a/includes/Storage/PageEditStash.php
+++ b/includes/Storage/PageEditStash.php
@@ -121,7 +121,7 @@ class PageEditStash {
 		$key = $this->getStashKey( $page, $this->getContentHash( $content ), $user );
 		$fname = __METHOD__;
 
-		// Use the master DB to allow for fast blocking locks on the "save path" where this
+		// Use the primary DB to allow for fast blocking locks on the "save path" where this
 		// value might actually be used to complete a page edit. If the edit submission request
 		// happens before this edit stash requests finishes, then the submission will block until
 		// the stash request finishes parsing. For the lock acquisition below, there is not much
diff --git a/includes/Storage/PageUpdater.php b/includes/Storage/PageUpdater.php
index 9059c94bb8d..037c66f901b 100644
--- a/includes/Storage/PageUpdater.php
+++ b/includes/Storage/PageUpdater.php
@@ -760,7 +760,7 @@ class PageUpdater {
 			}
 		}
 
-		// Load the data from the master database if needed. Needed to check flags.
+		// Load the data from the primary database if needed. Needed to check flags.
 		// NOTE: This grabs the parent revision as the CAS token, if grabParentRevision
 		// wasn't called yet. If the page is modified by another process before we are done with
 		// it, this method must fail (with status 'edit-conflict')!
diff --git a/includes/cache/LinkCache.php b/includes/cache/LinkCache.php
index 4bfd0d6a495..7adb09e62ef 100644
--- a/includes/cache/LinkCache.php
+++ b/includes/cache/LinkCache.php
@@ -111,7 +111,7 @@ class LinkCache implements LoggerAwareInterface {
 	}
 
 	/**
-	 * General accessor to get/set whether the master DB should be used
+	 * General accessor to get/set whether the primary DB should be used
 	 *
 	 * This used to also set the FOR UPDATE option (locking the rows read
 	 * in order to avoid link table inconsistency), which was later removed
diff --git a/includes/externalstore/ExternalStoreDB.php b/includes/externalstore/ExternalStoreDB.php
index b683decc831..067669e41b8 100644
--- a/includes/externalstore/ExternalStoreDB.php
+++ b/includes/externalstore/ExternalStoreDB.php
@@ -200,7 +200,7 @@ class ExternalStoreDB extends ExternalStoreMedium {
 	}
 
 	/**
-	 * @param array $server Master DB server configuration array for LoadBalancer
+	 * @param array $server Primary DB server configuration array for LoadBalancer
 	 * @return string|bool Database domain ID or false
 	 */
 	private function getDomainId( array $server ) {
diff --git a/includes/libs/objectcache/ReplicatedBagOStuff.php b/includes/libs/objectcache/ReplicatedBagOStuff.php
index b247093efcd..2cd3e4216ef 100644
--- a/includes/libs/objectcache/ReplicatedBagOStuff.php
+++ b/includes/libs/objectcache/ReplicatedBagOStuff.php
@@ -48,7 +48,7 @@ class ReplicatedBagOStuff extends BagOStuff {
 	/**
 	 * Constructor. Parameters are:
 	 *   - writeFactory: ObjectFactory::getObjectFromSpec array yielding BagOStuff.
-	 *      This object will be used for writes (e.g. the master DB).
+	 *      This object will be used for writes (e.g. the primary DB).
 	 *   - readFactory: ObjectFactory::getObjectFromSpec array yielding BagOStuff.
 	 *      This object will be used for reads (e.g. a replica DB).
 	 *   - sessionConsistencyWindow: Seconds to read from the master source for a key
diff --git a/includes/libs/rdbms/ChronologyProtector.php b/includes/libs/rdbms/ChronologyProtector.php
index 73dadd6c273..b2c7cde956b 100644
--- a/includes/libs/rdbms/ChronologyProtector.php
+++ b/includes/libs/rdbms/ChronologyProtector.php
@@ -116,7 +116,7 @@ use Wikimedia\WaitConditionLoop;
  * These are the expectations a site administrator must meet for chronology protection:
  *
  * - If the application is run from multiple data centers, then you must designate one of them
- *   as the "primary DC". The primary DC is where the master database is located, from which
+ *   as the "primary DC". The primary DC is where the primary database is located, from which
  *   replication propagates to replica databases in that same DC and any other DCs.
  *
  * - Web requests that use the POST verb, or carry a `UseDC=master` cookie, must be routed to
@@ -125,7 +125,7 @@ use Wikimedia\WaitConditionLoop;
  *   An exception is requests carrying the `Promise-Non-Write-API-Action: true` header,
  *   which use the POST verb for large read queries, but don't actually require the primary DC.
  *
- *   If you have legacy extensions deployed that perform queries on the master database during
+ *   If you have legacy extensions deployed that perform queries on the primary database during
  *   GET requests, then you will have to identify a way to route any of its relevant URLs to the
  *   primary DC as well, or to accept that their reads do not enjoy chronology protection, and
  *   that writes may be slower (due to cross-dc latency).
@@ -278,7 +278,7 @@ class ChronologyProtector implements LoggerAwareInterface {
 	/**
 	 * Update client "session consistency" replication position for an end-of-life ILoadBalancer
 	 *
-	 * This remarks the replication position of the master DB if this request made writes to
+	 * This remarks the replication position of the primary DB if this request made writes to
 	 * it using the provided ILoadBalancer instance.
 	 *
 	 * @internal This method should only be called from LBFactory.
diff --git a/includes/libs/rdbms/TransactionProfiler.php b/includes/libs/rdbms/TransactionProfiler.php
index 9e1b2a4be0d..34c377793d8 100644
--- a/includes/libs/rdbms/TransactionProfiler.php
+++ b/includes/libs/rdbms/TransactionProfiler.php
@@ -204,9 +204,9 @@ class TransactionProfiler implements LoggerAwareInterface {
 	 *
 	 * @param string $server DB server
 	 * @param string|null $db DB name
-	 * @param bool $isMaster
+	 * @param bool $isPrimary
 	 */
-	public function recordConnection( $server, $db, bool $isMaster ) {
+	public function recordConnection( $server, $db, bool $isPrimary ) {
 		// Report when too many connections happen...
 		if ( $this->pingAndCheckThreshold( 'conns' ) ) {
 			$this->reportExpectationViolated(
@@ -216,8 +216,8 @@ class TransactionProfiler implements LoggerAwareInterface {
 			);
 		}
 
-		// Report when too many master connections happen...
-		if ( $isMaster && $this->pingAndCheckThreshold( 'masterConns' ) ) {
+		// Report when too many primary connections happen...
+		if ( $isPrimary && $this->pingAndCheckThreshold( 'masterConns' ) ) {
 			$this->reportExpectationViolated(
 				'masterConns',
 				"[connect to $server ($db)]",
diff --git a/includes/libs/rdbms/connectionmanager/ConnectionManager.php b/includes/libs/rdbms/connectionmanager/ConnectionManager.php
index 872f23d1bb1..d22e3092f4a 100644
--- a/includes/libs/rdbms/connectionmanager/ConnectionManager.php
+++ b/includes/libs/rdbms/connectionmanager/ConnectionManager.php
@@ -104,7 +104,7 @@ class ConnectionManager {
 	}
 
 	/**
-	 * Returns a connection to the master DB, for updating. The connection should later be released
+	 * Returns a connection to the primary DB, for updating. The connection should later be released
 	 * by calling releaseConnection().
 	 *
 	 * @since 1.29
@@ -145,7 +145,7 @@ class ConnectionManager {
 	}
 
 	/**
-	 * Returns a connection ref to the master DB, for updating.
+	 * Returns a connection ref to the primary DB, for updating.
 	 *
 	 * @since 1.29
 	 *
diff --git a/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php b/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php
index efbb42e98b7..8b254d3bfb9 100644
--- a/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php
+++ b/includes/libs/rdbms/connectionmanager/SessionConsistentConnectionManager.php
@@ -24,18 +24,18 @@ namespace Wikimedia\Rdbms;
 /**
  * Database connection manager.
  *
- * This manages access to master and replica databases. It also manages state that indicates whether
- * the replica databases are possibly outdated after a write operation, and thus the master database
+ * This manages access to primary and replica databases. It also manages state that indicates whether
+ * the replica databases are possibly outdated after a write operation, and thus the primary 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 SessionConsistentConnectionManager.
  * Services accessing unrelated sets of information may prefer to not share a
  * SessionConsistentConnectionManager, so they can still perform read operations against replica
- * databases after a (unrelated, per the assumption) write operation to the master database.
+ * databases after a (unrelated, per the assumption) write operation to the primary database.
  * Generally, sharing a SessionConsistentConnectionManager improves consistency (by avoiding race
  * conditions due to replication lag), but can reduce performance (by directing more read
- * operations to the master database server).
+ * operations to the primary database server).
  *
  * @since 1.29
  *
diff --git a/includes/libs/rdbms/database/DBConnRef.php b/includes/libs/rdbms/database/DBConnRef.php
index c11ff00aeb5..43f636590f8 100644
--- a/includes/libs/rdbms/database/DBConnRef.php
+++ b/includes/libs/rdbms/database/DBConnRef.php
@@ -69,7 +69,7 @@ class DBConnRef implements IDatabase {
 	}
 
 	/**
-	 * @return int DB_PRIMARY when this *requires* the master DB, otherwise DB_REPLICA
+	 * @return int DB_PRIMARY when this *requires* the primary DB, otherwise DB_REPLICA
 	 * @since 1.33
 	 */
 	public function getReferenceRole() {
@@ -775,12 +775,12 @@ class DBConnRef implements IDatabase {
 	 * Error out if the role is not DB_PRIMARY
 	 *
 	 * Note that the underlying connection may or may not itself be read-only.
-	 * It could even be to a writable master (both server-side and to the application).
+	 * It could even be to a writable primary (both server-side and to the application).
 	 * This error is meant for the case when a DB_REPLICA handle was requested but a
 	 * a write was attempted on that handle regardless.
 	 *
-	 * In configurations where the master DB has some generic read load or is the only server,
-	 * DB_PRIMARY/DB_REPLICA will sometimes (or always) use the same connection to the master DB.
+	 * In configurations where the primary DB has some generic read load or is the only server,
+	 * DB_PRIMARY/DB_REPLICA will sometimes (or always) use the same connection to the primary DB.
 	 * This does not effect the role of DBConnRef instances.
 	 * @throws DBReadOnlyRoleError
 	 */
diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index 78557416d3d..4219447833b 100644
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -76,7 +76,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	/** @var object|resource|null Database connection */
 	protected $conn;
 
-	/** @var IDatabase|null Lazy handle to the master DB this server replicates from */
+	/** @var IDatabase|null Lazy handle to the primary DB this server replicates from */
 	private $lazyMasterHandle;
 
 	/** @var string|null Server that this instance is currently connected to */
@@ -93,7 +93,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	protected $agent;
 	/** @var string Replication topology role of the server; one of the class ROLE_* constants */
 	protected $topologyRole;
-	/** @var string|null Host (or address) of the root master server for the replication topology */
+	/** @var string|null Host (or address) of the root primary server for the replication topology */
 	protected $topologyRootMaster;
 	/** @var array<string,mixed> Connection parameters used by initConnection() and open() */
 	protected $connectionParams;
@@ -411,7 +411,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	 *   - lbInfo: Optional map of field/values for the managing load balancer instance.
 	 *      The "master" and "replica" fields are used to flag the replication role of this
 	 *      database server and whether methods like getLag() should actually issue queries.
-	 *   - lazyMasterHandle: lazy-connecting IDatabase handle to the master DB for the cluster
+	 *   - lazyMasterHandle: lazy-connecting IDatabase handle to the primary DB for the cluster
 	 *      that this database belongs to. This is used for replication status purposes.
 	 *   - connLogger: Optional PSR-3 logger interface instance.
 	 *   - queryLogger: Optional PSR-3 logger interface instance.
diff --git a/includes/libs/rdbms/database/DatabaseMysqlBase.php b/includes/libs/rdbms/database/DatabaseMysqlBase.php
index 28c7936a1b9..c6b182f26e6 100644
--- a/includes/libs/rdbms/database/DatabaseMysqlBase.php
+++ b/includes/libs/rdbms/database/DatabaseMysqlBase.php
@@ -853,7 +853,7 @@ abstract class DatabaseMysqlBase extends Database {
 				$this->getLogContext( [ 'method' => __METHOD__, 'raw_pos' => $pos ] )
 			);
 
-			return 0; // this is a copy of a read-only dataset with no master DB
+			return 0; // this is a copy of a read-only dataset with no primary DB
 		} elseif ( $this->lastKnownReplicaPos && $this->lastKnownReplicaPos->hasReached( $pos ) ) {
 			$this->queryLogger->debug(
 				"Bypassed replication wait; replication known to have reached {raw_pos}",
diff --git a/includes/libs/rdbms/lbfactory/ILBFactory.php b/includes/libs/rdbms/lbfactory/ILBFactory.php
index 17e2058c31b..18eba67a515 100644
--- a/includes/libs/rdbms/lbfactory/ILBFactory.php
+++ b/includes/libs/rdbms/lbfactory/ILBFactory.php
@@ -46,7 +46,7 @@ interface ILBFactory {
 	 *
 	 * @param array $conf Array with keys:
 	 *  - localDomain: A DatabaseDomain or domain ID string.
-	 *  - readOnlyReason: Reason the master DB is read-only if so [optional]
+	 *  - readOnlyReason: Reason the primary DB is read-only if so [optional]
 	 *  - srvCache: BagOStuff instance for server cache [optional]
 	 *  - cpStash: BagOStuff instance for ChronologyProtector store [optional]
 	 *    See [ChronologyProtector requirements](@ref ChronologyProtector-storage-requirements).
diff --git a/includes/libs/rdbms/lbfactory/LBFactory.php b/includes/libs/rdbms/lbfactory/LBFactory.php
index be058dc2f96..c479c614849 100644
--- a/includes/libs/rdbms/lbfactory/LBFactory.php
+++ b/includes/libs/rdbms/lbfactory/LBFactory.php
@@ -310,7 +310,7 @@ abstract class LBFactory implements ILBFactory {
 		$this->forEachLBCallMethod( 'approveMasterChanges', [ $options, $fname, $this->id ] );
 		// Log the DBs and methods involved in multi-DB transactions
 		$this->logIfMultiDbTransaction();
-		// Actually perform the commit on all master DB connections and revert DBO_TRX
+		// Actually perform the commit on all primary DB connections and revert DBO_TRX
 		$this->forEachLBCallMethod( 'commitMasterChanges', [ $fname, $this->id ] );
 		// Run all post-commit callbacks in a separate step
 		$this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
@@ -328,7 +328,7 @@ abstract class LBFactory implements ILBFactory {
 
 		$this->trxRoundStage = self::ROUND_ROLLING_BACK;
 		$this->trxRoundId = false;
-		// Actually perform the rollback on all master DB connections and revert DBO_TRX
+		// Actually perform the rollback on all primary DB connections and revert DBO_TRX
 		$this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname, $this->id ] );
 		// Run all post-commit callbacks in a separate step
 		$this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
diff --git a/includes/libs/rdbms/loadbalancer/LoadBalancer.php b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
index e17c5ec137d..4ed07fa793a 100644
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -159,7 +159,7 @@ class LoadBalancer implements ILoadBalancer {
 
 	/** Default 'waitTimeout' when unspecified */
 	private const MAX_WAIT_DEFAULT = 10;
-	/** Seconds to cache master DB server read-only status */
+	/** Seconds to cache primary DB server read-only status */
 	private const TTL_CACHE_READONLY = 5;
 
 	private const KEY_LOCAL = 'local';
@@ -362,7 +362,7 @@ class LoadBalancer implements ILoadBalancer {
 	 * @return int Sanitized bitfield
 	 */
 	private function sanitizeConnectionFlags( $flags, $i, $domain ) {
-		// Whether an outside caller is explicitly requesting the master database server
+		// Whether an outside caller is explicitly requesting the primary database server
 		if ( $i === self::DB_PRIMARY || $i === $this->getWriterIndex() ) {
 			$flags |= self::CONN_INTENT_WRITABLE;
 		}
@@ -372,7 +372,7 @@ class LoadBalancer implements ILoadBalancer {
 			// resorting to row locks (e.g. FOR UPDATE) or to make small out-of-band commits
 			// during larger transactions. This is useful for avoiding lock contention.
 
-			// Master DB server attributes (should match those of the replica DB servers)
+			// Primary DB server attributes (should match those of the replica DB servers)
 			$attributes = $this->getServerAttributes( $this->getWriterIndex() );
 			if ( $attributes[Database::ATTR_DB_LEVEL_LOCKING] ) {
 				// The RDBMS does not support concurrent writes (e.g. SQLite), so attempts
@@ -962,7 +962,7 @@ class LoadBalancer implements ILoadBalancer {
 		$serverIndex = $this->getConnectionIndex( $i, $groups, $domain );
 		// Get an open connection to that server (might trigger a new connection)
 		$conn = $this->getServerConnection( $serverIndex, $domain, $flags );
-		// Set master DB handles as read-only if there is high replication lag
+		// Set primary DB handles as read-only if there is high replication lag
 		if (
 			$conn &&
 			$serverIndex === $this->getWriterIndex() &&
@@ -1015,15 +1015,15 @@ class LoadBalancer implements ILoadBalancer {
 
 		// Make sure that flags like CONN_TRX_AUTOCOMMIT are respected by this handle
 		$this->enforceConnectionFlags( $conn, $flags );
-		// Set master DB handles as read-only if the load balancer is configured as read-only
-		// or the master database server is running in server-side read-only mode. Note that
+		// Set primary DB handles as read-only if the load balancer is configured as read-only
+		// or the primary database server is running in server-side read-only mode. Note that
 		// replica DB handles are always read-only via Database::assertIsWritableMaster().
 		// Read-only mode due to replication lag is *avoided* here to avoid recursion.
 		if ( $i === $this->getWriterIndex() ) {
 			if ( $this->readOnlyReason !== false ) {
 				$readOnlyReason = $this->readOnlyReason;
 			} elseif ( $this->isMasterConnectionReadOnly( $conn, $flags ) ) {
-				$readOnlyReason = 'The master database server is running in read-only mode.';
+				$readOnlyReason = 'The primary database server is running in read-only mode.';
 			} else {
 				$readOnlyReason = false;
 			}
@@ -2125,7 +2125,7 @@ class LoadBalancer implements ILoadBalancer {
 		if ( $this->readOnlyReason !== false ) {
 			return $this->readOnlyReason;
 		} elseif ( $this->isMasterRunningReadOnly( $domainInstance ) ) {
-			return 'The master database server is running in read-only mode.';
+			return 'The primary database server is running in read-only mode.';
 		} elseif ( $this->getLaggedReplicaMode( $domain ) ) {
 			$genericIndex = $this->getExistingReaderIndex( self::GROUP_GENERIC );
 
@@ -2139,7 +2139,7 @@ class LoadBalancer implements ILoadBalancer {
 
 	/**
 	 * @note This method suppresses DBError exceptions in order to avoid severe downtime
-	 * @param IDatabase $conn Master connection
+	 * @param IDatabase $conn Primary connection
 	 * @param int $flags Bitfield of class CONN_* constants
 	 * @return bool Whether the entire server or currently selected DB/schema is read-only
 	 */
@@ -2375,7 +2375,7 @@ class LoadBalancer implements ILoadBalancer {
 				if ( !$masterConn ) {
 					throw new DBReplicationWaitError(
 						null,
-						"Could not obtain a master database connection to get the position"
+						"Could not obtain a primary database connection to get the position"
 					);
 				}
 				$pos = $masterConn->getMasterPos();
diff --git a/includes/libs/rdbms/loadmonitor/LoadMonitor.php b/includes/libs/rdbms/loadmonitor/LoadMonitor.php
index a9a8d2c8ec8..d9983e26622 100644
--- a/includes/libs/rdbms/loadmonitor/LoadMonitor.php
+++ b/includes/libs/rdbms/loadmonitor/LoadMonitor.php
@@ -117,7 +117,7 @@ class LoadMonitor implements ILoadMonitor {
 	 * @throws DBAccessError
 	 */
 	protected function getServerStates( array $serverIndexes, $domain ) {
-		// Represent the cluster by the name of the master DB
+		// Represent the cluster by the name of the primary DB
 		$cluster = $this->lb->getServerName( $this->lb->getWriterIndex() );
 
 		// Randomize logical TTLs to reduce stampedes
@@ -199,7 +199,7 @@ class LoadMonitor implements ILoadMonitor {
 	 * @throws DBAccessError
 	 */
 	protected function computeServerStates( array $serverIndexes, $domain, $priorStates ) {
-		// Check if there is just a master DB (no replication involved)
+		// Check if there is just a primary DB (no replication involved)
 		if ( $this->lb->getServerCount() <= 1 ) {
 			return $this->getPlaceholderServerStates( $serverIndexes );
 		}
@@ -209,11 +209,11 @@ class LoadMonitor implements ILoadMonitor {
 		$lagTimes = [];
 		$weightScales = [];
 		foreach ( $serverIndexes as $i ) {
-			$isMaster = ( $i == $this->lb->getWriterIndex() );
-			// If the master DB has zero load, then typical read queries do not use it.
+			$isPrimary = ( $i == $this->lb->getWriterIndex() );
+			// If the primary DB has zero load, then typical read queries do not use it.
 			// In that case, avoid connecting to it since this method might run in any
-			// datacenter, and the master DB might be geographically remote.
-			if ( $isMaster && $this->lb->getServerInfo( $i )['load'] <= 0 ) {
+			// datacenter, and the primary DB might be geographically remote.
+			if ( $isPrimary && $this->lb->getServerInfo( $i )['load'] <= 0 ) {
 				$lagTimes[$i] = 0;
 				// Callers only use this DB if they have *no choice* anyway (e.g. writes)
 				$weightScales[$i] = 1.0;
@@ -247,7 +247,7 @@ class LoadMonitor implements ILoadMonitor {
 
 			// Mark replication lag on this server as "false" if it is unreacheable
 			if ( !$conn ) {
-				$lagTimes[$i] = $isMaster ? 0 : false;
+				$lagTimes[$i] = $isPrimary ? 0 : false;
 				$this->replLogger->error(
 					__METHOD__ . ": host {db_server} is unreachable",
 					[ 'db_server' => $host ]
@@ -361,7 +361,7 @@ class LoadMonitor implements ILoadMonitor {
 	 */
 	private function getStatesCacheKey( $cache, array $serverIndexes ) {
 		sort( $serverIndexes );
-		// Lag is per-server, not per-DB, so key on the master DB name
+		// Lag is per-server, not per-DB, so key on the primary DB name
 		return $cache->makeGlobalKey(
 			'rdbms-server-states',
 			self::VERSION,
diff --git a/includes/logging/LogEventsList.php b/includes/logging/LogEventsList.php
index 2678db3698e..0a927c619c1 100644
--- a/includes/logging/LogEventsList.php
+++ b/includes/logging/LogEventsList.php
@@ -600,7 +600,7 @@ class LogEventsList extends ContextSource {
 	 * - wrap String Wrap the message in html (usually something like "<div ...>$1</div>").
 	 * - flags Integer display flags (NO_ACTION_LINK,NO_EXTRA_USER_LINKS)
 	 * - useRequestParams boolean Set true to use Pager-related parameters in the WebRequest
-	 * - useMaster boolean Use master DB
+	 * - useMaster boolean Use primary DB
 	 * - extraUrlParams array|bool Additional url parameters for "full log" link (if it is shown)
 	 * @return int Number of total log items (not limited by $lim)
 	 */
diff --git a/includes/objectcache/SqlBagOStuff.php b/includes/objectcache/SqlBagOStuff.php
index 07818c5ba4c..cc2edf66304 100644
--- a/includes/objectcache/SqlBagOStuff.php
+++ b/includes/objectcache/SqlBagOStuff.php
@@ -1188,7 +1188,7 @@ class SqlBagOStuff extends MediumSpecificBagOStuff {
 	}
 
 	/**
-	 * Wait for replica DBs to catch up to the master DB
+	 * Wait for replica DBs to catch up to the primary DB
 	 *
 	 * @param int|string $shardIndex Server index or self::SHARD_LOCAL/self::SHARD_GLOBAL
 	 * @return bool Success
diff --git a/includes/page/WikiPage.php b/includes/page/WikiPage.php
index 7b08cde1a61..8f471ebbe7e 100644
--- a/includes/page/WikiPage.php
+++ b/includes/page/WikiPage.php
@@ -215,7 +215,7 @@ class WikiPage implements Page, IDBAccessObject, PageRecord {
 	 * @param int $id Article ID to load
 	 * @param string|int $from One of the following values:
 	 *        - "fromdb" or WikiPage::READ_NORMAL to select from a replica DB
-	 *        - "fromdbmaster" or WikiPage::READ_LATEST to select from the master database
+	 *        - "fromdbmaster" or WikiPage::READ_LATEST to select from the primary database
 	 *
 	 * @return WikiPage|null
 	 * @deprecated since 1.36, use WikiPageFactory::newFromID instead
@@ -231,8 +231,8 @@ class WikiPage implements Page, IDBAccessObject, PageRecord {
 	 * @param stdClass $row Database row containing at least fields returned by getQueryInfo().
 	 * @param string|int $from Source of $data:
 	 *        - "fromdb" or WikiPage::READ_NORMAL: from a replica DB
-	 *        - "fromdbmaster" or WikiPage::READ_LATEST: from the master DB
-	 *        - "forupdate" or WikiPage::READ_LOCKING: from the master DB using SELECT FOR UPDATE
+	 *        - "fromdbmaster" or WikiPage::READ_LATEST: from the primary DB
+	 *        - "forupdate" or WikiPage::READ_LOCKING: from the primary DB using SELECT FOR UPDATE
 	 * @return WikiPage
 	 * @deprecated since 1.36, use WikiPageFactory::newFromRow instead
 	 */
@@ -465,8 +465,8 @@ class WikiPage implements Page, IDBAccessObject, PageRecord {
 	 * @param stdClass|string|int $from One of the following:
 	 *   - A DB query result object.
 	 *   - "fromdb" or WikiPage::READ_NORMAL to get from a replica DB.
-	 *   - "fromdbmaster" or WikiPage::READ_LATEST to get from the master DB.
-	 *   - "forupdate"  or WikiPage::READ_LOCKING to get from the master DB
+	 *   - "fromdbmaster" or WikiPage::READ_LATEST to get from the primary DB.
+	 *   - "forupdate"  or WikiPage::READ_LOCKING to get from the primary DB
 	 *     using SELECT FOR UPDATE.
 	 *
 	 * @return void
@@ -522,8 +522,8 @@ class WikiPage implements Page, IDBAccessObject, PageRecord {
 	 *
 	 * @param string|int $from One of the following:
 	 *   - "fromdb" or WikiPage::READ_NORMAL to get from a replica DB.
-	 *   - "fromdbmaster" or WikiPage::READ_LATEST to get from the master DB.
-	 *   - "forupdate"  or WikiPage::READ_LOCKING to get from the master DB
+	 *   - "fromdbmaster" or WikiPage::READ_LATEST to get from the primary DB.
+	 *   - "forupdate"  or WikiPage::READ_LOCKING to get from the primary DB
 	 *     using SELECT FOR UPDATE.
 	 *
 	 * @return bool
@@ -550,9 +550,9 @@ class WikiPage implements Page, IDBAccessObject, PageRecord {
 	 * @param stdClass|bool $data DB row containing fields returned by getQueryInfo() or false
 	 * @param string|int $from One of the following:
 	 *        - "fromdb" or WikiPage::READ_NORMAL if the data comes from a replica DB
-	 *        - "fromdbmaster" or WikiPage::READ_LATEST if the data comes from the master DB
+	 *        - "fromdbmaster" or WikiPage::READ_LATEST if the data comes from the primary DB
 	 *        - "forupdate"  or WikiPage::READ_LOCKING if the data comes from
-	 *          the master DB using SELECT FOR UPDATE
+	 *          the primary DB using SELECT FOR UPDATE
 	 */
 	public function loadFromRow( $data, $from ) {
 		$lc = MediaWikiServices::getInstance()->getLinkCache();
diff --git a/includes/page/WikiPageFactory.php b/includes/page/WikiPageFactory.php
index 98a487b65b5..ca61bf1d449 100644
--- a/includes/page/WikiPageFactory.php
+++ b/includes/page/WikiPageFactory.php
@@ -103,8 +103,8 @@ class WikiPageFactory {
 	 * @param stdClass $row Database row containing at least fields returned by getQueryInfo().
 	 * @param string|int $from Source of $data:
 	 *        - "fromdb" or WikiPage::READ_NORMAL: from a replica DB
-	 *        - "fromdbmaster" or WikiPage::READ_LATEST: from the master DB
-	 *        - "forupdate" or WikiPage::READ_LOCKING: from the master DB using SELECT FOR UPDATE
+	 *        - "fromdbmaster" or WikiPage::READ_LATEST: from the primary DB
+	 *        - "forupdate" or WikiPage::READ_LOCKING: from the primary DB using SELECT FOR UPDATE
 	 *
 	 * @return WikiPage
 	 */
@@ -120,7 +120,7 @@ class WikiPageFactory {
 	 * @param int $id Article ID to load
 	 * @param string|int $from One of the following values:
 	 *        - "fromdb" or WikiPage::READ_NORMAL to select from a replica DB
-	 *        - "fromdbmaster" or WikiPage::READ_LATEST to select from the master database
+	 *        - "fromdbmaster" or WikiPage::READ_LATEST to select from the primary database
 	 *
 	 * @return WikiPage|null Null when no page exists with that ID
 	 */
diff --git a/includes/revisiondelete/RevDelList.php b/includes/revisiondelete/RevDelList.php
index 02d67cd8722..ee189910f27 100644
--- a/includes/revisiondelete/RevDelList.php
+++ b/includes/revisiondelete/RevDelList.php
@@ -333,7 +333,7 @@ abstract class RevDelList extends RevisionListBase {
 	}
 
 	/**
-	 * Reload the list data from the master DB. This can be done after setVisibility()
+	 * Reload the list data from the primary DB. This can be done after setVisibility()
 	 * to allow $item->getHTML() to show the new data.
 	 */
 	public function reloadFromMaster() {
diff --git a/includes/upload/UploadFromChunks.php b/includes/upload/UploadFromChunks.php
index e7a9b037a4c..244c0c16f1a 100644
--- a/includes/upload/UploadFromChunks.php
+++ b/includes/upload/UploadFromChunks.php
@@ -282,7 +282,7 @@ class UploadFromChunks extends UploadFromFile {
 	 * Get the chunk db state and populate update relevant local values
 	 */
 	private function getChunkStatus() {
-		// get Master db to avoid race conditions.
+		// get primary db to avoid race conditions.
 		// Otherwise, if chunk upload time < replag there will be spurious errors
 		$dbw = $this->repo->getPrimaryDB();
 		$row = $dbw->selectRow(
diff --git a/includes/user/User.php b/includes/user/User.php
index 35f82bd8ee9..e54a39361cf 100644
--- a/includes/user/User.php
+++ b/includes/user/User.php
@@ -466,7 +466,7 @@ class User implements Authority, UserIdentity, UserEmailContact {
 			return false;
 		}
 
-		// Try cache (unless this needs data from the master DB).
+		// Try cache (unless this needs data from the primary DB).
 		// NOTE: if this thread called saveSettings(), the cache was cleared.
 		$latest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
 		if ( $latest ) {
@@ -856,7 +856,7 @@ class User implements Authority, UserIdentity, UserEmailContact {
 			$userQuery['joins']
 		);
 		if ( !$row ) {
-			// Try the master database...
+			// Try the primary database...
 			$dbw = $loadBalancer->getConnectionRef( DB_PRIMARY );
 			$row = $dbw->selectRow(
 				$userQuery['tables'],
diff --git a/maintenance/deleteOrphanedRevisions.php b/maintenance/deleteOrphanedRevisions.php
index ff986ab3ea7..9dceca43c50 100644
--- a/maintenance/deleteOrphanedRevisions.php
+++ b/maintenance/deleteOrphanedRevisions.php
@@ -85,7 +85,7 @@ class DeleteOrphanedRevisions extends Maintenance {
 	 * Do this inside a transaction
 	 *
 	 * @param int[] $id Array of revision id values
-	 * @param IDatabase $dbw Master DB handle
+	 * @param IDatabase $dbw Primary DB handle
 	 */
 	private function deleteRevs( array $id, $dbw ) {
 		$dbw->delete( 'revision', [ 'rev_id' => $id ], __METHOD__ );
diff --git a/maintenance/includes/DeleteLocalPasswords.php b/maintenance/includes/DeleteLocalPasswords.php
index 8f4ea339601..68d441f1f94 100644
--- a/maintenance/includes/DeleteLocalPasswords.php
+++ b/maintenance/includes/DeleteLocalPasswords.php
@@ -105,7 +105,7 @@ ERROR
 	}
 
 	/**
-	 * Get the master DB handle for the current user batch. This is provided for the benefit
+	 * Get the primary DB handle for the current user batch. This is provided for the benefit
 	 * of authentication extensions which subclass this and work with wiki farms.
 	 * @return IMaintainableDatabase
 	 */
diff --git a/maintenance/initSiteStats.php b/maintenance/initSiteStats.php
index c92719ea6e8..346d54a920d 100644
--- a/maintenance/initSiteStats.php
+++ b/maintenance/initSiteStats.php
@@ -36,7 +36,7 @@ class InitSiteStats extends Maintenance {
 		$this->addDescription( 'Re-initialise the site statistics tables' );
 		$this->addOption( 'update', 'Update the existing statistics' );
 		$this->addOption( 'active', 'Also update active users count' );
-		$this->addOption( 'use-master', 'Count using the master database' );
+		$this->addOption( 'use-master', 'Count using the primary database' );
 	}
 
 	public function execute() {
diff --git a/maintenance/mysql.php b/maintenance/mysql.php
index c548857cf96..441ecb5b784 100644
--- a/maintenance/mysql.php
+++ b/maintenance/mysql.php
@@ -37,7 +37,7 @@ class MysqlMaintenance extends Maintenance {
 		parent::__construct();
 		$this->addDescription( "Execute the MySQL client binary. " .
 			"Non-option arguments will be passed through to mysql." );
-		$this->addOption( 'write', 'Connect to the master database', false, false );
+		$this->addOption( 'write', 'Connect to the primary database', false, false );
 		$this->addOption( 'group', 'Specify query group', false, true );
 		$this->addOption( 'host', 'Connect to a specific MySQL server', false, true );
 		$this->addOption( 'list-hosts', 'List the available DB hosts', false, false );
diff --git a/maintenance/showJobs.php b/maintenance/showJobs.php
index b2fde8ed2a5..f4039d3ee75 100644
--- a/maintenance/showJobs.php
+++ b/maintenance/showJobs.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * Report number of jobs currently waiting in master database.
+ * Report number of jobs currently waiting in primary database.
  *
  * Based on runJobs.php
  *
@@ -29,7 +29,7 @@ require_once __DIR__ . '/Maintenance.php';
 
 /**
  * Maintenance script that reports the number of jobs currently waiting
- * in master database.
+ * in the primary database.
  *
  * @ingroup Maintenance
  */
@@ -43,7 +43,7 @@ class ShowJobs extends Maintenance {
 
 	public function __construct() {
 		parent::__construct();
-		$this->addDescription( 'Show number of jobs waiting in master database' );
+		$this->addDescription( 'Show number of jobs waiting in primary database' );
 		$this->addOption( 'group', 'Show number of jobs per job type' );
 		$this->addOption( 'list', 'Show a list of all jobs instead of counts' );
 		$this->addOption( 'type', 'Only show/count jobs of a given type', false, true );
diff --git a/maintenance/sql.php b/maintenance/sql.php
index 161bd6983e6..1d443b07072 100644
--- a/maintenance/sql.php
+++ b/maintenance/sql.php
@@ -48,7 +48,7 @@ class MwSql extends Maintenance {
 		$this->addOption( 'wikidb',
 			'The database wiki ID to use if not the current one', false, true );
 		$this->addOption( 'replicadb',
-			'Replica DB server to use instead of the master DB (can be "any")', false, true );
+			'Replica DB server to use instead of the primary DB (can be "any")', false, true );
 	}
 
 	public function execute() {
diff --git a/maintenance/updateArticleCount.php b/maintenance/updateArticleCount.php
index 7247a8ad49d..c8416bb3706 100644
--- a/maintenance/updateArticleCount.php
+++ b/maintenance/updateArticleCount.php
@@ -37,7 +37,7 @@ class UpdateArticleCount extends Maintenance {
 		parent::__construct();
 		$this->addDescription( 'Count of the number of articles and update the site statistics table' );
 		$this->addOption( 'update', 'Update the site_stats table with the new count' );
-		$this->addOption( 'use-master', 'Count using the master database' );
+		$this->addOption( 'use-master', 'Count using the primary database' );
 	}
 
 	public function execute() {
diff --git a/tests/phpunit/MediaWikiIntegrationTestCase.php b/tests/phpunit/MediaWikiIntegrationTestCase.php
index 792ea7fb545..7eda0480c2f 100644
--- a/tests/phpunit/MediaWikiIntegrationTestCase.php
+++ b/tests/phpunit/MediaWikiIntegrationTestCase.php
@@ -1564,10 +1564,10 @@ abstract class MediaWikiIntegrationTestCase extends PHPUnit\Framework\TestCase {
 	}
 
 	/**
-	 * Gets master database connections for all of the ExternalStoreDB
+	 * Gets primary database connections for all of the ExternalStoreDB
 	 * stores configured in $wgDefaultExternalStore.
 	 *
-	 * @return Database[] Array of Database master connections
+	 * @return Database[] Array of Database primary connections
 	 */
 	protected static function getExternalStoreDatabaseConnections() {
 		global $wgDefaultExternalStore;
diff --git a/tests/phpunit/includes/Revision/RevisionRendererTest.php b/tests/phpunit/includes/Revision/RevisionRendererTest.php
index f0881d2a439..ed776f53701 100644
--- a/tests/phpunit/includes/Revision/RevisionRendererTest.php
+++ b/tests/phpunit/includes/Revision/RevisionRendererTest.php
@@ -72,11 +72,11 @@ class RevisionRendererTest extends MediaWikiIntegrationTestCase {
 
 	/**
 	 * @param int $maxRev
-	 * @param bool $useMaster
+	 * @param bool $usePrimary
 	 * @return RevisionRenderer
 	 */
-	private function newRevisionRenderer( $maxRev = 100, $useMaster = false ) {
-		$dbIndex = $useMaster ? DB_PRIMARY : DB_REPLICA;
+	private function newRevisionRenderer( $maxRev = 100, $usePrimary = false ) {
+		$dbIndex = $usePrimary ? DB_PRIMARY : DB_REPLICA;
 
 		$db = $this->getMockDatabaseConnection( $maxRev );
 
diff --git a/tests/phpunit/includes/db/LBFactoryTest.php b/tests/phpunit/includes/db/LBFactoryTest.php
index 6c8ca12843f..a073a3aae93 100644
--- a/tests/phpunit/includes/db/LBFactoryTest.php
+++ b/tests/phpunit/includes/db/LBFactoryTest.php
@@ -260,7 +260,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 		$m1Pos = new MySQLMasterPos( 'db1034-bin.000976/843431247', $now );
 		$m2Pos = new MySQLMasterPos( 'db1064-bin.002400/794074907', $now );
 
-		// Master DB 1
+		// Primary DB 1
 		/** @var IDatabase|\PHPUnit\Framework\MockObject\MockObject $mockDB1 */
 		$mockDB1 = $this->getMockBuilder( IDatabase::class )
 			->disableOriginalConstructor()
@@ -268,7 +268,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 		$mockDB1->method( 'writesOrCallbacksPending' )->willReturn( true );
 		$mockDB1->method( 'lastDoneWrites' )->willReturn( $now );
 		$mockDB1->method( 'getMasterPos' )->willReturn( $m1Pos );
-		// Load balancer for master DB 1
+		// Load balancer for primary DB 1
 		$lb1 = $this->getMockBuilder( LoadBalancer::class )
 			->disableOriginalConstructor()
 			->getMock();
@@ -289,7 +289,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 		$lb1->method( 'getMasterPos' )->willReturn( $m1Pos );
 		$lb1->method( 'getReplicaResumePos' )->willReturn( $m1Pos );
 		$lb1->method( 'getServerName' )->with( 0 )->willReturn( 'master1' );
-		// Master DB 2
+		// Primary DB 2
 		/** @var IDatabase|\PHPUnit\Framework\MockObject\MockObject $mockDB2 */
 		$mockDB2 = $this->getMockBuilder( IDatabase::class )
 			->disableOriginalConstructor()
@@ -297,7 +297,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 		$mockDB2->method( 'writesOrCallbacksPending' )->willReturn( true );
 		$mockDB2->method( 'lastDoneWrites' )->willReturn( $now );
 		$mockDB2->method( 'getMasterPos' )->willReturn( $m2Pos );
-		// Load balancer for master DB 2
+		// Load balancer for primary DB 2
 		$lb2 = $this->getMockBuilder( LoadBalancer::class )
 			->disableOriginalConstructor()
 			->getMock();
@@ -347,7 +347,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 
 		// (b) Second HTTP request
 
-		// Load balancer for master DB 1
+		// Load balancer for primary DB 1
 		$lb1 = $this->getMockBuilder( LoadBalancer::class )
 			->disableOriginalConstructor()
 			->getMock();
@@ -357,7 +357,7 @@ class LBFactoryTest extends MediaWikiIntegrationTestCase {
 		$lb1->method( 'getServerName' )->with( 0 )->willReturn( 'master1' );
 		$lb1->expects( $this->once() )
 			->method( 'waitFor' )->with( $m1Pos );
-		// Load balancer for master DB 2
+		// Load balancer for primary DB 2
 		$lb2 = $this->getMockBuilder( LoadBalancer::class )
 			->disableOriginalConstructor()
 			->getMock();
diff --git a/tests/phpunit/includes/db/LoadBalancerTest.php b/tests/phpunit/includes/db/LoadBalancerTest.php
index 66c7e9d14ca..53bcd9934b5 100644
--- a/tests/phpunit/includes/db/LoadBalancerTest.php
+++ b/tests/phpunit/includes/db/LoadBalancerTest.php
@@ -224,7 +224,7 @@ class LoadBalancerTest extends MediaWikiIntegrationTestCase {
 		global $wgDBserver, $wgDBname, $wgDBuser, $wgDBpassword, $wgDBtype, $wgSQLiteDataDir;
 
 		$servers = [
-			// Master DB
+			// Primary DB
 			0 => $srvExtra + [
 					'host' => $wgDBserver,
 					'dbname' => $wgDBname,
@@ -774,19 +774,19 @@ class LoadBalancerTest extends MediaWikiIntegrationTestCase {
 	public function testGetLazyConnectionRef() {
 		$lb = $this->newMultiServerLocalLoadBalancer();
 
-		$rMaster = $lb->getLazyConnectionRef( DB_PRIMARY );
+		$rPrimary = $lb->getLazyConnectionRef( DB_PRIMARY );
 		$rReplica = $lb->getLazyConnectionRef( 1 );
 		$this->assertFalse( $lb->getAnyOpenConnection( 0 ) );
 		$this->assertFalse( $lb->getAnyOpenConnection( 1 ) );
 
-		$rMaster->getType();
+		$rPrimary->getType();
 		$rReplica->getType();
-		$rMaster->getDomainID();
+		$rPrimary->getDomainID();
 		$rReplica->getDomainID();
 		$this->assertFalse( $lb->getAnyOpenConnection( 0 ) );
 		$this->assertFalse( $lb->getAnyOpenConnection( 1 ) );
 
-		$rMaster->query( "SELECT 1", __METHOD__ );
+		$rPrimary->query( "SELECT 1", __METHOD__ );
 		$this->assertNotFalse( $lb->getAnyOpenConnection( 0 ) );
 
 		$rReplica->query( "SELECT 1", __METHOD__ );