"
Optimize consuming from a single partition.
This gives us significant improvement with single, small mutations,
as shown with perf_mutation_readers, compared to the vector-based
flat_mutation_reader_from_mutations_v2.
These are expected to be common on the write path,
and can be optimized for view building.
results from: perf_mutation_readers -c1 --random-seed=840478750
(userspace cpu-frequency governer, 2.2GHz)
test iterations median mad min max
Before:
combined.one_row 720118 825.668ns 1.020ns 824.648ns 827.750ns
After:
combined.one_mutation 881482 751.157ns 0.397ns 750.211ns 751.912ns
combined.one_row 843270 756.553ns 0.303ns 755.889ns 757.911ns
The grand plan is to follow up
with make_flat_mutation_reader_from_frozen_mutation_v2
so that we can read directly from either a mutation
or frozen_mutation without having to unfreeze it e.g. in
table::push_view_replica_updates.
Test: unit(dev)
Perf: perf_mutation_readers(release)
"
* tag 'flat_mutation_reader_from_mutation-v3' of https://github.com/bhalevy/scylla:
perf: perf_mutation_readers: add one_mutation case
test: mutation_query_test: make make_source static
mutation readers: refactor make_flat_mutation_reader_from_mutation*_v2
mutation readers: add make_flat_mutation_reader_from_mutation_v2
readers: delete slice_mutation.hh
test: flat_mutation_reader_test: mock_consumer: add debug logging
test: flat_mutation_reader_test: mock_consumer: make depth counter signed
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