feat: add additional logging for database errors

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/DB/Connection.php

 	/** @var DbDataCollector|null */
 	protected $dbDataCollector = null;
 
+	private ?array $transactionBacktrace = null;
+
 	/**
 	 * Initializes a new instance of the Connection class.
 	 *
 		$sql = $this->adapter->fixupStatement($sql);
 		$this->queriesExecuted++;
 		$this->logQueryToFile($sql);
-		return parent::executeQuery($sql, $params, $types, $qcp);
+		try {
+			return parent::executeQuery($sql, $params, $types, $qcp);
+		} catch (\Exception $e) {
+			$this->logDatabaseException($e);
+			throw $e;
+		}
 	}
 
 	/**
 		$sql = $this->adapter->fixupStatement($sql);
 		$this->queriesExecuted++;
 		$this->logQueryToFile($sql);
-		return parent::executeUpdate($sql, $params, $types);
+		try {
+			return parent::executeUpdate($sql, $params, $types);
+		} catch (\Exception $e) {
+			$this->logDatabaseException($e);
+			throw $e;
+		}
 	}
 
 	/**
 		$sql = $this->adapter->fixupStatement($sql);
 		$this->queriesExecuted++;
 		$this->logQueryToFile($sql);
-		return (int)parent::executeStatement($sql, $params, $types);
+		try {
+			return (int)parent::executeStatement($sql, $params, $types);
+		} catch (\Exception $e) {
+			$this->logDatabaseException($e);
+			throw $e;
+		}
 	}
 
 	protected function logQueryToFile(string $sql): void {
 	 * @deprecated 15.0.0 - use unique index and "try { $db->insert() } catch (UniqueConstraintViolationException $e) {}" instead, because it is more reliable and does not have the risk for deadlocks - see https://github.com/nextcloud/server/pull/12371
 	 */
 	public function insertIfNotExist($table, $input, array $compare = null) {
-		return $this->adapter->insertIfNotExist($table, $input, $compare);
+		try {
+			return $this->adapter->insertIfNotExist($table, $input, $compare);
+		} catch (\Exception $e) {
+			$this->logDatabaseException($e);
+			throw $e;
+		}
 	}
 
 	public function insertIgnoreConflict(string $table, array $values) : int {
-		return $this->adapter->insertIgnoreConflict($table, $values);
+		try {
+			return $this->adapter->insertIgnoreConflict($table, $values);
+		} catch (\Exception $e) {
+			$this->logDatabaseException($e);
+			throw $e;
+		}
 	}
 
 	private function getType($value) {
 			return new Migrator($this, $config, $dispatcher);
 		}
 	}
+
+	public function beginTransaction() {
+		if (!$this->inTransaction()) {
+			$this->transactionBacktrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
+		}
+		return parent::beginTransaction();
+	}
+
+	public function commit() {
+		$result = parent::commit();
+		if ($this->getTransactionNestingLevel() === 0) {
+			$this->transactionBacktrace = null;
+		}
+		return $result;
+	}
+
+	public function rollBack() {
+		$result = parent::rollBack();
+		if ($this->getTransactionNestingLevel() === 0) {
+			$this->transactionBacktrace = null;
+		}
+		return $result;
+	}
+
+	public function logDatabaseException(\Exception $exception): void {
+		if ($exception instanceof Exception\UniqueConstraintViolationException) {
+			$this->logger->info($exception->getMessage(), ['exception' => $exception, 'transaction' => $this->transactionBacktrace]);
+		} else {
+			$this->logger->error($exception->getMessage(), ['exception' => $exception, 'transaction' => $this->transactionBacktrace]);
+		}
+	}
 }

lib/private/DB/ConnectionAdapter.php

 			throw new \Exception('Database ' . $platform::class . ' not supported');
 		}
 	}
+
+	public function logDatabaseException(\Exception $exception) {
+		$this->inner->logDatabaseException($exception);
+	}
 }

lib/private/DB/QueryBuilder/QueryBuilder.php

 			]);
 		}
 
-		$result = $this->queryBuilder->execute();
+		try {
+			$result = $this->queryBuilder->execute();
+		} catch (\Exception $e) {
+			$this->connection->logDatabaseException($e);
+			throw $e;
+		}
 		if (is_int($result)) {
 			return $result;
 		}