JingsongLi commented on PR #556: URL: https://github.com/apache/paimon-rust/pull/556#issuecomment-5042357807
`global-index.thread-num` is supposed to be the maximum concurrency for global-index I/O, but the same value is applied independently at both levels: up to N bucket futures here, and each bucket starts up to N exact-file futures in `bucket_search_batch`. Therefore, with the default N=32, a single search can issue up to 1024 exact-file searches concurrently, and concurrent queries multiply this further. This differs from Java's shared `GlobalIndexReadThreadPool`, which caps the whole search at N. I reproduced this with two buckets, two files per bucket, and `concurrency=2`; four file searches were active simultaneously. Could we use one shared semaphore/concurrency budget across both levels, or only fan out at one level, and add a test that verifies the peak concurrency? -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
