c/topic_table: notify ntp delta waiters in batches #24761
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CI test resultstest results on build#60552
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When installing a controller snapshot or creating a topic with many partitions, the number of pending deltas can grow quite large. Notify waiters in batches to avoid stalls. This should also fix the problem with controller_backend notification handler that will spawn a lot of ready tasks if the task quota is exceeded.
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| auto end = _pending_ntp_deltas.end(); | ||
| if (end - begin > batch_size) { | ||
| end = begin + batch_size; | ||
| } |
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Have you tried auto end = std::min(begin + batch_size, _pending_ntp_deltas.end())? According to the iterator category tag It should just work.
| _pending_ntp_deltas.cbegin(), _pending_ntp_deltas.cend()}; | ||
| if (!changes.empty()) { | ||
| const ssize_t batch_size = 128; | ||
| for (size_t i = 0; i < _pending_ntp_deltas.size(); i += batch_size) { |
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Nit. Have you checked whether it's okay to increment this iterator past the end? From what I can see, it's down to the iterator implementation, so it's not guaranteed by the iterator traits. Currently iterator position is stored as an index, so it looks safe. But if we change it to e.g. a pair of chunk_id and pos_in_chunk, this code may become invalid. WDYT?
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When installing a controller snapshot or creating a topic with many partitions, the number of pending deltas can grow quite large. Notify waiters in batches to avoid stalls. This should also fix the problem with controller_backend notification handler that will spawn a lot of ready tasks if the task quota is exceeded.
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