- Reorder JOINs and predicates to reduce the computational cost.
- Remove the memory-costly "pu.url" predicates from the "where" clause, as the DB has no empty urls anymore.
- Make sure we remove the assignments of all "not-successful", old, worker-reports, even for the ones which failed to be renamed to indicate success or failure, or failed to be executed by the background threads (and thus never reached the renaming stage).
- Submit each task immediately for execution, instead of waiting for a scheduling thread to send all gathered tasks (up to that point) to the ExecutorService (and block until they are finished, before it can start again).
- Hold the Future of each submitted task to a synchronized-list to check the result of each task at a scheduled time.
- Reduce the cpu-time to assure the Service can shut down, by checking if there are "actively" and "about-to-be-executed" tasks, at the same time. Instead of having to rely on the additional checking of the "shutdown"-status of each worker to verify that no active task exist.
- Improve the threads' shutdown procedure.
- Retrieve the assignments by checking only the publication-urls against the "attempt", "assignment" and "payload" tables, not the IDs. This change allow us to: a) avoid re-attempting urls which have already been attempted multiple times (by different id-url pairs), b) avoid aggregating urls which are already inside the "payload" or "assignment" tables, even when they are related with other IDs.
In the end, we only care about the urls when choosing which records should be aggregated.
- Improve performance by using the "anti join" operator, where it fits, in order to allow the engine to use the faster "hash" operations.
- Fix an issue, where assignments, having an above-zero attempt_count, were finding their way to the results, just because they were prioritized based on their boost_level or pub_year. Apart from retrying the old failed assignments sooner, the non-yet-processed boosted-publications were pushed out to the workers much slower.
- Simplify the query, by removing the internal "ordering" and "limit", which had performance benefits when we did not need additional ordering for "level" and "pub_year". Back then, we wanted to apply the final orderings to as few rows as possible.
- Avoid processing publications which will be published in the next 5 years, counting from each "current" year, since they are not providing full-texts yet. Still allow the invalid publication-years like "2566", "9999", etc.
- Upon completing processing a workerReport, the name of the json-file will be appended with "successful" or "failed".
- Avoid deleting immediately the failed workerReports.
- Add a scheduling task to process leftover failed workerReports from previous executions of the service, only once, 12 hours after startup, in order for the workers to have participated and filled the "workersInfoMap".
- Add a scheduling task to process leftover failed workerReports from the current execution, regularly.
- Fix not iterating through the workers' subDirs when checking the last-access-time of workerReports.
- Fix not deleting the assignment records from the DB, when a failed leftover workerReport gets deleted.
- Code refactoring.
Lampros Smyrnaios