}

				return errors.New("inner rollback")
			}); err == nil {
				t.Fatalf("nested transaction has no error")
			}

			return errors.New("rollback")
		}); err == nil {
			t.Fatalf("nested transaction should returns error")
		}

		if err := tx.First(&User{}, "name = ?", user1.Name).Error; err == nil {
			t.Fatalf("Should not find rollbacked record")
		}

	} else {
		db.AddError(ErrInvalidTransaction)
	}
	return db
}

// Rollback rollbacks the changes in a transaction
func (db *DB) Rollback() *DB {
	if committer, ok := db.Statement.ConnPool.(TxCommitter); ok && committer != nil {
		if !reflect.ValueOf(committer).IsNil() {
			db.AddError(committer.Rollback())
		}
	} else {
		db.AddError(ErrInvalidTransaction)
	}
	return db
}

    //                                                                           Roll-back
    //                                                                           =========
    @Override
    public void rollback() {
        for (MultipartFormFile formFile : elementsFile.values()) {
            formFile.destroy();
        }
    }

    // ===================================================================================

  * Minimum memory limit is 4MB. This is a docker limitation
  * Minimum CPU limits is 10m. This is a Linux Kernel limitation
  * “kubectl rollout undo” (i.e. rollback) will hang on paused deployments, because
paused deployments can’t be rolled back (this is expected), and the command
waits for rollback events to return the result. Users should use “kubectl
rollout resume” to resume a deployment before rolling back.

	}

	if err := tx.Rollback().Error; err != nil {
		t.Fatalf("failed to rollback transaction: %v", err)
	}

	count2, err := gorm.G[User](DB).Where("name like ?", "TestGenericsTransaction%").Count(ctx, "*")
	if err != nil {
		t.Fatalf("Count failed: %v", err)
	}
	if count2 != 0 {
		t.Errorf("expected 0 records after rollback, got %d", count2)
	}
}

你可以使用 `async` 或一般函式。

**FastAPI** 都會正確處理，和一般相依相同。

///

## 同時使用 `yield` 與 `try` 的相依 { #a-dependency-with-yield-and-try }

如果在含 `yield` 的相依中使用 `try` 區塊，你會接收到使用該相依時拋出的任何例外。

例如，如果在中途的某段程式碼、其他相依，或某個路徑操作中，讓資料庫交易「rollback」或產生了任何例外，你都會在你的相依中接收到該例外。

因此，你可以在相依內用 `except SomeException` 來攔截特定例外。

同樣地，你可以使用 `finally` 來確保無論是否有例外都會執行結束步驟。

{* ../../docs_src/dependencies/tutorial007_py310.py hl[3,5] *}

For example, if some code at some point in the middle, in another dependency or in a *path operation*, made a database transaction "rollback" or created any other exception, you would receive the exception in your dependency.

So, you can look for that specific exception inside the dependency with `except SomeException`.

            byte[] newKey = deriveKey(currentKey, rotationLabel, String.valueOf(System.currentTimeMillis()).getBytes(), currentKey.length);

            // Archive old key (keep last version for rollback)
            String archiveId = sessionId + ".v" + currentVersion;
            storeSessionKeyInternal(archiveId, currentKey, "AES");

            // Store new key

	if err = selfupdate.CommitBinary(opts); err != nil {
		if rerr := selfupdate.RollbackError(err); rerr != nil {
			return AdminError{
				Code:       AdminUpdateApplyFailure,
				Message:    fmt.Sprintf("Failed to rollback from bad update: %v", rerr),
				StatusCode: http.StatusInternalServerError,
			}
		}
		var pathErr *os.PathError
		if errors.As(err, &pathErr) {
			return AdminError{
				Code: AdminUpdateApplyFailure,

### Go-Live

- [ ] Schedule maintenance window
- [ ] Final incremental data sync
- [ ] Switch DNS or endpoints to Fess
- [ ] Monitor logs for errors
- [ ] Monitor search performance metrics
- [ ] Have rollback plan ready

### Post-Migration

- [ ] Monitor search quality and relevance
- [ ] Tune ranking and boosting settings
- [ ] Set up regular crawl schedules
- [ ] Configure backup and disaster recovery