N624-debu opened a new pull request, #14900: URL: https://github.com/apache/lucene/pull/14900
# [Draft] SharedMergeScheduler using shared thread pool for multi-tenant merge scheduling This draft PR introduces a prototype `SharedMergeScheduler`, which extends `MergeScheduler` and routes all merge tasks through a shared thread pool across `IndexWriter` instances. ## Motivation In multi-tenant environments (e.g., Solr, Elasticsearch), many `IndexWriter`s may coexist in the same JVM. The default Lucene behavior assigns each writer its own `ConcurrentMergeScheduler` and thread pool, which can lead to resource oversubscription and inefficient coordination. This implementation introduces a new merge scheduler that centralizes merge execution via a shared thread pool. This idea builds on feedback from [GitHub issue #13883](https://github.com/apache/lucene/issues/13883), where contributors suggested exploring a dedicated scheduler based on Java's executor framework, rather than modifying the existing `ConcurrentMergeScheduler`. ## Implementation Highlights - Adds a new class `SharedMergeScheduler` in `lucene.index` - Implements the `merge(MergeSource, MergeTrigger)` method using the public `MergeSource` API - Uses a static `Executors.newFixedThreadPool(4)` as a prototype shared executor - Keeps `ConcurrentMergeScheduler` unchanged for easier evaluation and iteration ## Next Steps - Add lifecycle management and graceful shutdown to the executor - Evaluate fairness or throttling strategies across writers - Potentially combine with a centralized merge manager - Seek feedback on architecture fit and maintainability --- This PR is opened to propose and evaluate a shared-thread-pool merge scheduler design, and to gather feedback for further development. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
