feat: expose estimated_size for stateful set operations - #177
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Cover the accumulating set-operation operators that hold real heap state: HllUnion, CpcUnion, ThetaUnion, ThetaIntersection, TupleUnion, and TupleIntersection. The a-not-b operators are stateless and thus exempt. UnionState and IntersectionState in thetacommon gain heap-only helpers that delegate to SketchHashTable, mirroring the sketch-level pattern from apache#136. For HllUnion and CpcUnion, whose state embeds a full sketch inline, the sketch's inline size is subtracted to avoid double counting against size_of::<Self>(). Addresses apache#137
tisonkun
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| #[test] | ||
| fn test_union_estimated_size() { | ||
| let mut union = CpcUnion::new(11); | ||
| let empty_size = union.estimated_size(); | ||
| assert!(empty_size > 0); | ||
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| let mut sketch = CpcSketch::new(11); | ||
| for i in 0..1000 { | ||
| sketch.update(i); | ||
| } | ||
| union.update(&sketch); | ||
| assert!(union.estimated_size() > empty_size); | ||
| } |
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Please try to follow 05b5ad5 to assert exact values of estimated_size.
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Thanks for your contribution @Renkai!
Looks like a good suppliment.
cc @notfilippo @ariesdevil FYI you may review how HllSktech and ThetaSketch/TupleSketch provides their estimated size.
Comments inline above.
Signed-off-by: Renkai Ge <gaelookair@gmail.com>
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Follow-up of #174, addressing part of #137.
While all sketch types expose
estimated_size()now, the stateful set-operation operators — which hold real heap state while accumulating updates — don't report their footprint yet. This patch addsestimated_size()to:HllUnion— delegates to its internalHllSketchgadgetCpcUnion— covers both internal states (Accumulatorsketch andBitMatrix)ThetaUnion/ThetaIntersection— via a heap-only helper onUnionState/IntersectionStateTupleUnion/TupleIntersection— same shared helpersThe a-not-b operators are stateless (a one-shot computation over two inputs), so they are intentionally exempt.
Implementation notes:
UnionState::estimated_size()/IntersectionState::estimated_size()report heap allocations only (delegating toSketchHashTable::estimated_size()), so the public operators can composesize_of::<Self>() + state.estimated_size()without double counting.HllUnionandCpcUnion, whose state embeds a full sketch inline, the inner sketch's inline size is subtracted for the same reason.Note that an operator's footprint cannot be inferred from its result sketch: the internal table keeps capacity headroom per its load factor and resize history (and
CpcUnion's bit matrix is fixed atk * 8bytes), whereasto_sketch()produces a tightly packed copy.Tests: one case per operator in the existing integration targets. Verified with
cargo x check,cargo x test(incl. Go snapshots), andcargo x lint.