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…y run (#7611) `compareKey()` resolved an ambiguous binary-search landing point to the boundary of the run of entries that compare equal to the search key only when the search key was a PARTIAL key. The guard reads as though a run can exist only under a partial key. It cannot: a page holds one entry per TRANSACTION that wrote the key - each commit appends its own (key, rids) entry instead of merging into the previous one - so runs under a FULL key are the normal state of every non-unique index built by batched loading. `LSMTreeIndexUnderlyingPageCursor.getKeys()` merges a key group FORWARD from wherever the cursor is parked, so an ascending scan that starts mid-run never sees the entries before it. An indexed `>=` (and the lower half of `BETWEEN`) therefore under-reported by floor((k-1)/2) of the rows equal to the bound for a run of k, silently, with the unindexed scan over the same rows correct - so adding an index to make the query faster changed its answer. `>`, `=`, `<=` and `IN` were not affected: a strict lower bound discards the run anyway, an upper bound is enforced per entry rather than by seeking, and equality goes through purpose 1, which already collects the whole run. The resolution moves out of the two near-identical `compareKey()` overrides and into `LSMTreeIndexAbstract.seekRunBoundary()`, called from `lookupInPage()` - the only place holding the bracket the binary search has already narrowed. That makes it: - correct for full keys, not only partial ones, in both the mutable and the compacted index; - a BINARY search over that bracket rather than the linear walk the overrides used, so a long run costs O(log k) comparisons instead of O(k) (`findFirstEntryOfSameKey` stays as it is for purpose 1, which needs every position in the run, not just its edge); - written once instead of twice, which is what lets the explicit `findFirstEntryOfSameKey` in `LSMTreeIndexCompacted.searchInCurrentPage()` - the ascending half of the same problem, patched locally - go away with one source of truth left. The descending direction was already masked by the page cursor walking back to the leftmost entry of a group before merging, but the seek now lands on the run's last entry in its own right rather than relying on that. `Issue7611IndexedRangeLowerBoundTest` asserts an indexed bound against an unindexed twin holding identical rows, at every run length the defect distinguishes (k=1..41, the shortfall being floor((k-1)/2)), for every spelling of the bound, in both scan directions through `range()`, across a `compact()` at a size that fills many index pages, over a run mixing live rows, deleted rows and a re-insert, and on the batched ISO-date shape the defect was found on. All six fail on the previous code. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Included review availability: Your plan provides up to 4 included reviews per hour; 3 remain after this review. 📝 WalkthroughWalkthroughThe change centralizes duplicate-key run-boundary resolution for LSM index iterators. Mutable and compacted indexes use this logic for full and partial keys. Regression coverage checks indexed and unindexed scans before and after compaction. ChangesDuplicate-key range scan correction
Priority: ➖ Normal Estimated code review effort: 3 (Moderate) | ~25 minutes Change: Bug fix · Severity of issue fixed: Medium Suggested reviewers: Merge Risk: ⚪ Minimal · up to No merge-blocking issue remains identified for the duplicate-key iterator boundary change. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
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Up to standards ✅🟢 Issues
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| Metric | Results |
|---|---|
| Complexity | 7 |
🟢 Coverage 100.00% diff coverage · -6.35% coverage variation
Metric Results Coverage variation ✅ -6.35% coverage variation Diff coverage ✅ 100.00% diff coverage Coverage variation details
Coverable lines Covered lines Coverage Common ancestor commit (a2084b6) 180427 149082 82.63% Head commit (994d6b2) 212849 (+32422) 162360 (+13278) 76.28% (-6.35%) Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch:
<coverage of head commit> - <coverage of common ancestor commit>Diff coverage details
Coverable lines Covered lines Diff coverage Pull request (#7616) 34 34 100.00% Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified:
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`@engine/src/test/java/com/arcadedb/index/Issue7611IndexedRangeLowerBoundTest.java`:
- Around line 1-287: Extend Issue7611IndexedRangeLowerBoundTest with a NOTUNIQUE
composite-index scenario that queries a leading-key prefix using a partial
composite key, asserting all matching rows before and after
IndexInternal.compact(). Exercise the iterator-purpose 2/3 path through the
existing query/index APIs and verify results against an equivalent unindexed
dataset, while preserving the current full-key coverage.
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📒 Files selected for processing (4)
engine/src/main/java/com/arcadedb/index/lsm/LSMTreeIndexAbstract.javaengine/src/main/java/com/arcadedb/index/lsm/LSMTreeIndexCompacted.javaengine/src/main/java/com/arcadedb/index/lsm/LSMTreeIndexMutable.javaengine/src/test/java/com/arcadedb/index/Issue7611IndexedRangeLowerBoundTest.java
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ReviewSolid fix, and unusually well-verified for an index-internals change. I read through Correctness
Code quality
Performance
Security
Test coverage
Nice writeup in the PR description, too, the shortfall formula and the "index makes the query faster and changes its answer" framing made the review much faster. |
…7611) Every other case in the fixture scans a single-property index, so it only ever passes a FULL key. The run-boundary resolution used to live in the two `compareKey()` overrides behind a `convertedKeys.length < binaryKeyTypes.length` guard - covering exactly the composite-prefix case (#6592, #6694) and nothing else - and this change moved it into `seekRunBoundary()` for full and partial keys alike. A regression on the prefix path would therefore have passed the whole fixture unnoticed. Adds a NOTUNIQUE composite index whose leading-key prefix group is a run: the prefix is scanned through SQL and through `range()` in both directions, before and after `compact()`, against an unindexed twin holding the same rows. All seven tests fail with the boundary resolution disabled. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The walk it describes moved to LSMTreeIndexAbstract.seekRunBoundary() in this branch. The two other comments that explained the same mechanism were updated with the move; this third one, on the fromPurpose root-page lookup, was missed, so a reader chasing "compareKey()'s PARTIAL MATCHING walk" landed on a method that no longer has one. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Review I traced through lookupInPage() / seekRunBoundary() and the two compareKey() overrides in detail, plus the callers in LSMTreeIndexMutable, LSMTreeIndexCompacted and LSMTreeIndexCursor. Overall this is a solid, well-reasoned fix with an unusually thorough regression suite. A few notes below, nothing I would consider blocking. Correctness
Performance The PR description frames the win as O(log k) instead of O(k) for a run of length k, which is true, but it understates a secondary effect worth being aware of: for the very common case where no duplicate run exists, the old partial-key-only walk (findFirstEntryOfSameKey) cost one wasted comparison against the immediate neighbor, then stopped. The new seekRunBoundary() instead runs a full binary search over whatever [low, high] bracket the caller's search converged with, which can be much wider than 1 even when only a single entry actually matches (e.g. a match found on the very first probed mid still carries the whole-page bracket). That's an O(log page-entries) cost now paid on every ascending/descending iterator lookup that resolves to a match, for both unique and non-unique indexes, where before it was effectively free for full keys (the guard skipped it entirely) and explicitly skipped for unique indexes at the searchInCurrentPage() call site (result.found && !unique). That guard's removal is very likely correct rather than an oversight: a unique index can still carry a tombstone-plus-live-reinsert pair for the same key across separate transactions (remove() appends a tombstone entry rather than mutating in place), so unique doesn't actually rule out a same-key run on a page. I don't think reintroducing a unique short-circuit is safe, but it might be worth a one-line note in seekRunBoundary()'s Javadoc that this cost is intentionally not gated on unique, since a future reader will likely wonder the same thing I did. If the extra binary-search steps ever show up in profiling of read-heavy workloads, a galloping/exponential probe outward from matched before falling back to bisection would recover the O(1) no-run case while keeping O(log k) for genuine runs. Not requesting this now, just flagging it as a possible follow-up. Tests The Issue7611IndexedRangeLowerBoundTest suite is excellent: it isolates the exact run-length threshold (k=3), checks every SQL spelling that reaches the index, exercises both scan directions directly through RangeIndex.range(), mixes in tombstones/re-inserts, and forces the check across a compact(). The follow-up commit closing the partial-key blind spot in the fixture is a good catch of every other test in this file only exercising a full key. One small thing I verified rather than assumed: the tests use count() with a WHERE clause. Per this repo's engine notes, count() only takes the cached-counter fast path for an unfiltered SELECT count(*) FROM Type (SelectExecutionPlanner.isMinimalQuery() requires whereClause == null), so these filtered queries do a real accurate count and are fine as ground truth, just calling it out since it's a common trap in this codebase. holdsAcrossManyPagesAndACompaction and batchedDateLoadMatchesTheUnindexedScan insert on the order of 10-40k documents across many small transactions; depending on how long that runs in CI it might be a candidate for @tag(slow) per this repo's convention, though I didn't measure actual wall-clock time. Note on verification I reviewed this statically (read through the diff, the surrounding LSM index code, and the call graph) rather than running mvn verify myself, since I didn't have a way to execute a build in this session. The PR description states the full engine suite (14,946 tests) passes with only one pre-existing, unrelated failure; I did not independently re-run that, so it's worth a second confirmation from CI before merge if that hasn't already happened. Generated with Claude Code |
…e bracket (#7611) The bisection introduced with seekRunBoundary() searches the entire [low, high] bracket the caller's binary search converged with. That bracket can span the whole page even when a single entry matches - a match found on the first probed mid carries the full bracket - so every iterator lookup that resolved to a match paid O(log page-entries), including the no-run case, which for a full key used to cost nothing at all because the partial-key guard skipped the resolution outright. Galloping outward from the landing point in doubling strides before bisecting what the last stride jumped over restores that: ONE comparison when there is no run, O(log k) for a run of k, never the O(log page-entries) of a bracket-wide bisection. The gallop's `bad` is the virtual index one past the bracket edge when no mismatch is found before it, which the bisection never probes because it only ever probes strictly between `good` and `bad`. Also records in the Javadoc why the resolution is deliberately NOT gated on `unique`: remove() appends a tombstone entry rather than mutating in place, so a unique key deleted and re-inserted across two transactions owns a run like any other, and short-circuiting there would lose the older entry exactly as it was lost for non-unique keys. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
ReviewI read through Correctness The core algorithm looks sound:
Performance The gallop-before-bisect shape is the right choice given the stated goal (one comparison when there is no run, O(log k) for a run of k, never O(log page-entries) for a plain bisection over the whole bracket). I did not find a case where the loop does more probing than that. Test coverage Strong regression coverage: run lengths 1..41 pinned against the documented One nit on tagging: per this repo's Minor
Overall this is a careful, well-reasoned fix with a correctness argument that holds up under manual tracing, and the regression suite is thorough enough that it should catch a future regression on either the full-key or partial-key path. Isolating the defect down to the exact 🤖 Generated with Claude Code |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #7616 +/- ##
==========================================
+ Coverage 74.17% 74.19% +0.01%
==========================================
Files 1967 1967
Lines 180427 180446 +19
Branches 38002 38003 +1
==========================================
+ Hits 133838 133883 +45
+ Misses 31382 31361 -21
+ Partials 15207 15202 -5 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Fixes #7611.
The defect
compareKey()resolved an ambiguous binary-search landing point to the boundary of the run of entries that compare equal to the search key only when the search key was a PARTIAL key. The guard reads as though a run can exist only under a partial key. It cannot: a page holds one entry per transaction that wrote the key - each commit appends its own(key, rids)entry rather than merging into the previous one - so runs under a full key are the normal state of every non-unique index built by batched loading.LSMTreeIndexUnderlyingPageCursor.getKeys()merges a key group forward from wherever the cursor is parked, so an ascending scan that starts mid-run never sees the entries before it. An indexed>=(and the lower half ofBETWEEN) therefore under-reported byfloor((k-1)/2)of the rows equal to the bound for a run ofk: silently, with no error, and with the unindexed scan over the same rows correct - so adding an index to make the query faster changed its answer.>,=,<=andINwere not affected: a strict lower bound discards the run anyway, an upper bound is enforced per entry rather than by seeking, and equality goes throughpurpose == 1, which already collects the whole run.The reporter found it on a TPC-H Q6 shape (
l_shipdate >= '1994-01-01' AND l_shipdate < '1995-01-01'): 908,652 rows against the row scan's 909,455 at scale factor 1, every lost row withl_shipdateexactly equal to the lower bound.The fix
The issue suggests dropping the
convertedKeys.length < binaryKeyTypes.lengthguard in bothcompareKey()overrides. That is correct but leaves the resolution duplicated in two places and linear in the run length. This PR moves it instead intoLSMTreeIndexAbstract.seekRunBoundary(), called fromlookupInPage()- the only place holding the bracket the binary search has already narrowed (every entry below low compares HIGHER, every entry above high compares LOWER, so the run lies inside[low, high]). That makes the resolution:O(log k)comparisons instead ofO(k).findFirstEntryOfSameKeystays as it is forpurpose == 1, which needs every position in the run rather than just its edge;findFirstEntryOfSameKeyinLSMTreeIndexCompacted.searchInCurrentPage()- the ascending half of the same problem, patched locally - go away with one source of truth left.The descending direction was already masked by the page cursor walking back to the leftmost entry of a group before merging, but the seek now lands on the run's last entry in its own right rather than relying on that.
Verification
Issue7611IndexedRangeLowerBoundTestcompares an indexed type against an unindexed twin holding identical rows:inclusiveLowerBoundReturnsEveryRowAtTheBoundfloor((k-1)/2), so k=3 is the smallest failing case and k=1,2 must keep passing)everySpellingOfTheBoundAgreesWithTheUnindexedScan>=literal,>=parameter,BETWEEN,>= AND <=,IN,=,>,<=bothScanDirectionsSeekToTheBoundaryOfTheRunRangeIndex.range()deletesInsideTheRunResolveAgainstTheWiderScanholdsAcrossManyPagesAndACompactioncompact()(compaction used to reduce the loss without removing it)batchedDateLoadMatchesTheUnindexedScanAll six fail on the previous code and pass on this one. The engine suite is green: 14,946 tests, the only failure being
MultiColumnAggregationResultTest.emptySumAndCountStayZeroNotNaN, which fails identically onmainata2084b669and is unrelated (time-series NaN aggregation).🤖 Generated with Claude Code
Summary by CodeRabbit
BETWEEN, andINqueries using indexed fields.