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23e93a26b3
Refs: #9555 When running the "Kraken" dynamodb streams test to provoke the issued observed by QA, I noticed on my setup mainly two things: Large allocation stalls (+ warnings) and timeouts on read semaphores in DB. This tries to address the first issue, partly by making query_result_view serialization using chunked vector instead of linear one, and by introducing a streaming option for json return objects, avoiding linearizing to string before wire. Note that the latter has some overhead issues of its own, mainly data copying, since we essentially will be triple buffering (local, wrapped http stream, and final output stream). Still, normal string output will typically do a lot of realloc which is potential extra copies as well, so... This is not really performance tested, but with these tweaks I no longer get large alloc stalls at least, so that is a plus. :-) Closes #9713 * github.com:scylladb/scylla: alternator::executor: Use streamed result for scan etc if large result alternator::streams: Use streamed result in get_records if large result executor/server: Add routine to make stream object return rjson: Add print to stream of rjson::value query_idl: Make qr_partition::rows/query_result::partitions chunked