Bibliographic record
Abstract
'Big Data' analysis has become a central activity in business and science. Companies such as Facebook, Yahoo, and Google now own petabyte-scale data warehouses that are accessed on a regular basis. Terabyte-scale data warehouses are now common in many smaller organizations. This big data analysis is mostly supported by the MapReduce programming and execution model and its implementations, most notably Hadoop which is now one of the major big data platforms. Users of MapReduce often have analysis tasks that are too complex to express as one MapReduce job. Instead, they often use high-level query languages such as Pig Latin, Hive, or Jaql to express their complex analysis tasks. The compilers of these query languages translate queries into workflows of MapReduce jobs. Each job in such a workflow produces an output that is stored in the distributed file system used by the MapReduce system (e.g., HDFS in the case of Hadoop). These intermediate results are used as input by subsequent jobs in the workflow. The current practice is to delete these intermediate outputs after finishing the execution of the workflow. In our work, we developed ReStore, a system that improves the performance of workflows of MapReduce jobs generated from high-level query languages by storing the intermediate results of executed workflows and reusing them for future workflows submitted to the system. ReStore can be built on top of dataflow language processor such as Pig, which translates queries into workflows of MapReduce jobs. Each of these MapReduce jobs has a physical query execution plan that contains one or more physical operators that are executed by this job. ReStore rewrites the MapReduce jobs in a submitted workflow at the level of the physical query execution plan in order to reuse job outputs previously stored in the system. ReStore also stores the outputs of executed jobs for future reuse, and creates more reuse opportunities by storing the outputs of parts of jobs (which we call sub-jobs). We have implemented ReStore as an extension to the Pig dataflow system on top of Hadoop, and we experimentally demonstrated significant speedups on queries from the PigMix benchmark.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.005 | 0.009 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.003 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.005 |
| Open science | 0.005 | 0.005 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.005 | 0.005 |
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".