[bulk_executor] fix: add --persegment support to scancount (#92) - #49
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[bulk_executor] fix: add --persegment support to scancount (#92)#49relentlesscol wants to merge 2 commits into
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Unit tests assert: - DictAccumulator (AccumulatorParam subclass) exists for per-segment count propagation via Spark Accumulators (not plain dicts) - _count_data adds segment count to per_segment_accumulator - run() creates DictAccumulator when --persegment is set - run() prints per-segment counts when --persegment is set - Backward compat: no per-segment output without the flag E2e test (tests/e2e/commands/test_scancount_persegment_smoke.py): - Runs real Glue scancount --persegment against a transient table - Verifies per-segment output lines appear and sum to total
…labs#92) Implements per-segment item count reporting for scancount using a Spark Accumulator (DictAccumulator) to correctly propagate counts from executors to the driver. Plain dicts don't work in Spark's distributed model — only Accumulators do. Changes: - Add DictAccumulator(AccumulatorParam) that merges segment count dicts - Add per_segment_accumulator parameter to _count_data - Create per-segment accumulator in run() when persegment=True - Print per-segment breakdown after total count
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Closing as stale — fork-internal PR against the fork's own main. Branch is retained; reopen if this work resumes. |
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Summary
DictAccumulator(AccumulatorParam)to correctly propagate per-segment counts from Spark executors to the driver (plain dicts don't work in Spark's distributed model)per_segment_accumulatorparameter to_count_datawhich records{segment_id: count}after each segment completes--persegmentflag is set,run()creates the accumulator and prints a per-segment breakdown after the totalIssues addressed
scancountable to output item counts per segment to measure possible task execution skew awslabs/amazon-dynamodb-tools#92 — scancount --persegment: report per-segment item counts to detect data skewTest plan
test_scancount_persegment.pypass (DictAccumulator merging, _count_data integration, run() output)--persegment, output is unchanged