feat(append-only): amortize the compaction's commit-time seeks — prepaid puts carry no seek (GROVE_V4) - #830
feat(append-only): amortize the compaction's commit-time seeks — prepaid puts carry no seek (GROVE_V4)#830QuantumExplorer wants to merge 3 commits into
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…id puts carry no seek (GROVE_V4) Removes the last position-dependent figure of an append under the fixed model: the compacting append's commit-time seek count. - costs: KeyValueStorageCost::prepaid() / is_prepaid() — the cost info of a put whose owner billed bytes, key and the write in advance - storage: the RocksDB commit path and PrefixedRocksDbBatch::put charge a prepaid put no seek (only the append-only family's GROVE_V4 accounting issues such puts: MMR nodes, chunk blob, persisted MMR root, backfill) - bulk-append: amortized_compaction_seeks(chunk_power) = ceil((1 blob + 32 merges + 1 root) / 2^chunk_power) charged on every append (1 from chunk_power 6); the compacting append is charged the slot + record seeks it does not issue (BUFFER_CHURN_PUTS) - estimators: the 66-seek MAX_COMPACTION_PUTS reservation becomes the amortized share (max at chunk_power 1 for worst/undeclared); the PDS model counts both fixed state-root reads - tests: full OperationCost equality across positions for CT / bulk / PDS / legacy CT; seek bound + prefix sums; prepaid puts carry no seek Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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📝 WalkthroughWalkthroughThe change adds a prepaid marker to storage costs, skips seek billing for prepaid puts, and updates bulk-append accounting. Cost estimates, storage producers, documentation, and tests now use amortized compaction seeks and explicit prepaid writes. ChangesPrepaid storage-cost contract
Estimated code review effort: 3 (Moderate) | ~25 minutes Merge Risk: 🟡 Moderate · up to The change can overcount commit-time seeks for supported prepaid write paths and may break downstream code that constructs the public cost type directly. The PR is not merge-ready until the accounting behavior and compatibility impact are fixed or explicitly accepted. 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
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Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## develop #830 +/- ##
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+ Coverage 92.44% 92.48% +0.03%
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Files 292 292
Lines 90277 90361 +84
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+ Hits 83454 83566 +112
+ Misses 6823 6795 -28
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Reviewed at commit 98b638d970e05ce920b24b4d43591d9608ebaf13. The compaction-put bound, per-append seek amortization, and estimator adjustments are internally coherent, and the focused affected-crate and GroveDB accounting tests pass. I found one blocking issue at the storage API boundary: the new prepaid state is structurally indistinguishable from the existing default value, so the commit path can suppress seeks without evidence that they were prepaid. GitHub does not permit a change-request review from the PR author's account, so I am submitting this as a comment review with a blocking finding.
…-cost Default still pays its seek Review follow-up on #830: `prepaid()` was structurally equal to `Default::default()`, so the commit path would have dropped the seek of any put passed `Some(Default::default())` (Merk does, for writes it charges no bytes for). `KeyValueStorageCost` now carries `prepaid: bool`, set only by `prepaid()`; `is_prepaid()` reads the marker. Regressions: Default and every other constructor are not prepaid, a sum with an unprepaid part is not, and a `Some(Default::default())` put is still charged its seek at commit beside a prepaid one that is not. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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In `@costs/src/storage_cost/key_value_cost.rs`:
- Around line 52-56: Preserve source compatibility for KeyValueStorageCost
struct literals in the 5.x grovedb-costs API: either remove the newly added
prepaid field and implement the behavior without changing the public struct
shape, or bump the crate’s major version from 5.0.1 to 6.0.0 and update the
release metadata consistently. Use KeyValueStorageCost and the crate version
configuration as the change points.
In `@storage/src/rocksdb_storage/storage.rs`:
- Around line 319-325: Apply the existing prepaid seek exemption used by normal
Put to PutAux, PutRoot, and PutMeta in storage.rs, and to direct Batch::put_aux
and Batch::put_root in batch.rs; alternatively reject prepaid costs for
unsupported variants. Add prepaid seek-accounting tests covering each supported
put variant and both batch paths in tests.rs, including the specified affected
sites.
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📒 Files selected for processing (24)
costs/src/storage_cost/key_value_cost.rscosts/tests/coverage_regression.rsdocs/book/src/bulk-append-tree.mddocs/book/src/commitment-tree.mddocs/crates/costs.mdgrovedb-bulk-append-tree/src/cost/mod.rsgrovedb-bulk-append-tree/src/lib.rsgrovedb-bulk-append-tree/src/tree/append.rsgrovedb-bulk-append-tree/src/tree/storage_accounting_tests.rsgrovedb-commitment-tree/src/commitment_tree/cost/mod.rsgrovedb-merkle-mountain-range/src/storage_adapter.rsgrovedb-private-document-store/src/store.rsgrovedb-version/src/version/bulk_append_tree_versions.rsgrovedb-version/src/version/v4.rsgrovedb/src/batch/estimated_costs/average_case_costs.rsgrovedb/src/batch/estimated_costs/mod.rsgrovedb/src/batch/estimated_costs/worst_case_costs.rsgrovedb/src/tests/append_storage_accounting_tests.rsmerk/src/tree/mod.rsmerk/src/tree/ops.rsstorage/src/rocksdb_storage/storage.rsstorage/src/rocksdb_storage/storage_context/batch.rsstorage/src/rocksdb_storage/tests.rsstorage/src/storage.rs
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Review follow-up on #830: PutAux / PutRoot / PutMeta on the StorageBatch commit path and put_aux / put_root on the direct PrefixedRocksDbBatch now skip the seek for KeyValueStorageCost::prepaid() exactly as the data put does; test covers every variant on both paths beside ordinary puts. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Summary
Follow-up to #829 (now merged). After #829 the one figure a
CommitmentTreeInsert/ bulk-append /PrivateDocumentStoreappend still varied by position was the commit-time seek count of the compacting append: the storage batch charges one seek per put, and that append writes the chunk blob +trailing_ones(chunks)MMR nodes + the persisted root instead of its slot and record. This PR removes that residual, so the whole charge is now position-independent.Prepaid puts carry no seek.
KeyValueStorageCostgains an explicitprepaid: boolmarker (set only by the newKeyValueStorageCost::prepaid()constructor, read byis_prepaid()) for a put whose owner billed everything about it in advance — bytes, key, and the write itself. A zero-costDefaultis NOT prepaid and keeps paying its seek (Merk passesSome(Default::default())for writes it charges no bytes for). The RocksDB commit path (continue_write_batch: data, aux, roots and meta puts) and the directPrefixedRocksDbBatchputs (data, aux, roots) charge a prepaid put no seek. Downstream: struct-literal constructions ofKeyValueStorageCostneed the new field (prepaid: false, or..Default::default()). Only the append-only family's GROVE_V4 accounting issues prepaid puts (the MMR store'sLeafValueStorageCost::Prepaid, the persisted MMR root, its legacy backfill), so no shipped cost moves.The compaction's puts are amortized as a seek share.
amortized_compaction_seeks(chunk_power) = ⌈MAX_COMPACTION_PUTS_PER_CHUNK / 2^chunk_power⌉withMAX_COMPACTION_PUTS_PER_CHUNK = 1 + 32 + 1(blob, ≤ 32 MMR merges with 32-bit MMR keys, persisted root) — 1 seek per append fromchunk_power6 (so at the shielded pool's 11), 17 atchunk_power1 — charged on every append under the fixed model, as a per-chunk bound so every prefix of the tree's life stays prepaid. The compacting append, whose own puts are all prepaid, is charged the slot + record seeks it does not issue (BUFFER_CHURN_PUTS = 2), exactly as it already carries their byte churn. Its seek count is therefore every other append's.Estimators replace the 66-seek
MAX_COMPACTION_PUTSreservation with the amortized share (max_amortized_compaction_seeks()— thechunk_power1 figure — on the worst-case and undeclared-layer arms), so the seek estimate is tight; the PDS model now counts both fixed state-root reads (persisted MMR root + last record), an under-count the old slack had hidden.What this means for a
CommitmentTreeInsertunder GROVE_V4Every figure — seeks, loaded bytes, added/replaced bytes, blake3, Sinsemilla — is identical at every position of the tree, the compacting append and a legacy tree's MMR-root backfill included. Nothing position-dependent remains.
Tests
prepaid()is prepaid,Default/ every other constructor is not, a sum with an unprepaid part is not.Some(Default::default())put at commit charges exactly two seeks (theirs) and is written all the same; every costed put variant (data / aux / roots / meta on theStorageBatchpath, data / aux / roots on the direct batch path) honours the marker.model reads + share(+ the churn seeks on the compacting one).assert_fixednow requires fullOperationCostequality (seeks included) across positions for CT (cp 4, cp 11 epoch boundary), bulk, PDS, a legacy (V3-seeded) CT's first V4 append, and the in-batch epoch boundary; estimate ≥ actual sweeps unchanged and tighter.🤖 Generated with Claude Code