Some oversized alloc high partition count improvements #24578
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StephanDollberg
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ballard26 and
mmaslankaprv
Retry command for Build#59797please wait until all jobs are finished before running the slash command |
CI test resultstest results on build#59797
test results on build#59908
test results on build#59952
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travisdowns
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Dec 17, 2024
travisdowns
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Dec 18, 2024
src/v/kafka/server/handlers/fetch.h
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| : fetches_per_shard() { | ||
| fetches_per_shard.reserve(shards); | ||
| for (size_t i = 0; i < shards; i++) { | ||
| auto& fps = fetches_per_shard.emplace_back(start_time); |
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IMO it's better to just change the shard_fetch ctor to take time & shard now, and then you can pass them both to emplace and void this weird thing where we fill in the shard after (should be no slower, may be faster). Then we don't leave shard uninit any more which is good.
I believe it was me who did it like this, mostly just to avail myself of the "n copies" constructor but we aren't using that any more.
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(approving though so feel free to ignore)
travisdowns
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travisdowns
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For super high partition topics at high partition density these can lead to oversized allocs due to the use of `absl::flat_hash_map`. Switch to chunked_hash_map.
`ntp_fetch_config` is 250 bytes. When doing super wide reads of 500-1000k partitions (quite niche) this goes above the oversized alloc threshold. Switch to chunked_vector. Switch responses too for uniformity.
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Address some oversized alloc in niche cases like super wide reads and super large topics.
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