Real-time quantification and classification of consistency anomalies in multi-tier architectures
Bibliographic record
Abstract
While online transaction processing applications heavily rely on the transactional properties provided by the underlying infrastructure, they often choose to not use the highest isolation level, i.e., serializability, because of the potential performance implications of costly strict two-phase locking concurrency control. Instead, modern transaction systems, consisting of an application server tier and a database tier, offer several levels of isolation providing a trade-off between performance and consistency. While it is fairly well known how to identify the anomalies that are possible under a certain level of isolation, it is much more difficult to quantify the amount of anomalies that occur during run-time of a given application. In this paper, we address this issue and present a new approach to detect, in realtime, consistency anomalies for arbitrary multi-tier applications. As the application is running, our tool detect anomalies online indicating exactly the transactions and data items involved. Furthermore, we classify the detected anomalies into patterns showing the business methods involved as well as their occurrence frequency. We use the RUBiS benchmark to show how the introduction of a new transaction type can have a dramatic effect on the number of anomalies for certain isolation levels, and how our tool can quickly detect such problem transactions. Therefore, our system can help designers to either choose an isolation level where the anomalies do not occur or to change the transaction design to avoid the anomalies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.004 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".