(improvement) perf: remove copies on the read path#734
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mykaul wants to merge 5 commits intoscylladb:masterfrom
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(improvement) perf: remove copies on the read path#734mykaul wants to merge 5 commits intoscylladb:masterfrom
mykaul wants to merge 5 commits intoscylladb:masterfrom
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Replace getvalue() with getbuffer() memoryview in _read_frame_header and frame body extraction to avoid full-buffer copies. Add _reset_buffer() helper using getbuffer()[pos:] instead of read() to reduce allocations. Wrap memoryview usage in try/finally to ensure release before mutation. Increase in_buffer_size from 4096 to 65536 to reduce recv() call overhead.
Introduce a lightweight BytesReader class that operates directly on bytes data without BytesIO overhead. Materializes memoryview to bytes once in __init__ instead of checking on every read(). Includes remaining_buffer() method for zero-copy handoff to Cython parsers.
Add offset parameter to BytesIOReader so it can start reading from the middle of an existing buffer, avoiding the full-body copy at the Python-to-Cython boundary. Update row_parser.pyx to use f.remaining_buffer() for zero-copy handoff with hasattr fallback. Track _initial_offset for error recovery.
13 BytesReader tests covering read operations, remaining_buffer(), memoryview materialization, empty data, and EOFError handling. 9 BytesIOReader tests covering offset initialization, boundary conditions, read behavior with offset, and error cases.
…pact Standalone benchmark (no cluster required) that constructs synthetic RESULT/ROWS wire-format bodies and measures ProtocolHandler.decode_message() throughput across 8 scenarios (small to 16MB, narrow to 20-column wide). Pins to a single CPU core via sched_setaffinity for consistent results. Supports both Cython and pure-Python paths, with --cprofile option.
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#630 would have helped with wide_5k_doubles of course. |
mykaul
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This patch set aims to reduce the memory copies we perform in the read path, to improve overall performance - mainly reduce latency on the processing side of the driver receiving the payload.
This is more effective on larger payloads of course.
Comparison to master:
(note - we can see that wide_5k_doubles is bottlenecked on something else - CPU processing of this payload - unpacking it. This may be optimized in a different PR)
./docs/source/.Fixes:annotations to PR description.