4 files changed, 43 insertions, 10 deletions

diff --git a/lib/private/DB/Adapter.php b/lib/private/DB/Adapter.php
index 8f1b8e6d75f..edd8c1bf023 100644
--- a/lib/private/DB/Adapter.php
+++ b/lib/private/DB/Adapter.php
@@ -28,11 +28,25 @@ class Adapter {
 	/**
 	 * @param string $table name
 	 *
-	 * @return int id of last insert statement
+	 * @return int id of last insert statement, 0 in case there was no INSERT before or it failed to get the ID
 	 * @throws Exception
 	 */
-	public function lastInsertId($table) {
-		return (int)$this->conn->realLastInsertId($table);
+	public function lastInsertId($table, bool $allowRetry = true): int {
+		$return = $this->conn->realLastInsertId($table);
+		if ($return === 0 && $allowRetry) {
+			/**
+			 * During a reconnect we are losing the connection and when the
+			 * realLastInsertId call is the one triggering the reconnect, it
+			 * does not return the ID. But inside the reconnect, we were able
+			 * to save the last insert id, so calling it a second time is going
+			 * to be successful.
+			 * We can not return the result on the initial call, as we are already
+			 * way deeper in the stack performing the actual database query on
+			 * the doctrine driver.
+			 */
+			return $this->lastInsertId($table, false);
+		}
+		return $return;
 	}
 
 	/**
diff --git a/lib/private/DB/AdapterOCI8.php b/lib/private/DB/AdapterOCI8.php
index 0a509090bca..f5ad9f7c934 100644
--- a/lib/private/DB/AdapterOCI8.php
+++ b/lib/private/DB/AdapterOCI8.php
@@ -8,7 +8,7 @@
 namespace OC\DB;
 
 class AdapterOCI8 extends Adapter {
-	public function lastInsertId($table) {
+	public function lastInsertId($table, bool $allowRetry = true): int {
 		if (is_null($table)) {
 			throw new \InvalidArgumentException('Oracle requires a table name to be passed into lastInsertId()');
 		}
diff --git a/lib/private/DB/AdapterPgSql.php b/lib/private/DB/AdapterPgSql.php
index db48c81c2c5..b321fcf4715 100644
--- a/lib/private/DB/AdapterPgSql.php
+++ b/lib/private/DB/AdapterPgSql.php
@@ -9,7 +9,7 @@ namespace OC\DB;
 
 class AdapterPgSql extends Adapter {
 
-	public function lastInsertId($table) {
+	public function lastInsertId($table, bool $allowRetry = true): int {
 		$result = $this->conn->executeQuery('SELECT lastval()');
 		$val = $result->fetchOne();
 		$result->free();
diff --git a/lib/private/DB/Connection.php b/lib/private/DB/Connection.php
index 96dd578b2ef..4ba2d2a341d 100644
--- a/lib/private/DB/Connection.php
+++ b/lib/private/DB/Connection.php
@@ -92,6 +92,8 @@ class Connection extends PrimaryReadReplicaConnection {
 	protected ShardConnectionManager $shardConnectionManager;
 	protected AutoIncrementHandler $autoIncrementHandler;
 	protected bool $isShardingEnabled;
+	protected bool $disableReconnect = false;
+	protected int $lastInsertId = 0;
 
 	public const SHARD_PRESETS = [
 		'filecache' => [
@@ -510,9 +512,9 @@ class Connection extends PrimaryReadReplicaConnection {
 	 * because the underlying database may not even support the notion of AUTO_INCREMENT/IDENTITY
 	 * columns or sequences.
 	 *
-	 * @param string $seqName Name of the sequence object from which the ID should be returned.
+	 * @param ?string $name Name of the sequence object from which the ID should be returned.
 	 *
-	 * @return int the last inserted ID.
+	 * @return int the last inserted ID, 0 in case there was no INSERT before or it failed to get the ID
 	 * @throws Exception
 	 */
 	public function lastInsertId($name = null): int {
@@ -526,8 +528,13 @@ class Connection extends PrimaryReadReplicaConnection {
 	 * @internal
 	 * @throws Exception
 	 */
-	public function realLastInsertId($seqName = null) {
-		return parent::lastInsertId($seqName);
+	public function realLastInsertId($seqName = null): int {
+		if ($this->lastInsertId !== 0) {
+			$lastInsertId = $this->lastInsertId;
+			$this->lastInsertId = 0;
+			return $lastInsertId;
+		}
+		return (int)parent::lastInsertId($seqName);
 	}
 
 	/**
@@ -896,11 +903,23 @@ class Connection extends PrimaryReadReplicaConnection {
 		if (
 			!isset($this->lastConnectionCheck[$this->getConnectionName()]) ||
 			time() <= $this->lastConnectionCheck[$this->getConnectionName()] + 30 ||
-			$this->isTransactionActive()
+			$this->isTransactionActive() ||
+			$this->disableReconnect
 		) {
 			return;
 		}
 
+		if ($this->getDatabaseProvider() === IDBConnection::PLATFORM_MYSQL) {
+			/**
+			 * Before reconnecting we save the lastInsertId, so that if the reconnect
+			 * happens between the INSERT executeStatement() and the getLastInsertId call
+			 * we are able to return the correct result after all.
+			 */
+			$this->disableReconnect = true;
+			$this->lastInsertId = (int)parent::lastInsertId();
+			$this->disableReconnect = false;
+		}
+
 		try {
 			$this->_conn->query($this->getDriver()->getDatabasePlatform()->getDummySelectSQL());
 			$this->lastConnectionCheck[$this->getConnectionName()] = time();