CONVO1
▐▛███▜▌ Claude Code v2.1.183 ▝▜█████▛▘ Opus 4.8 · Claude Team ▘▘ ▝▝ ~/.superset/worktrees/Arius7/migrate-v5-v7-2
❯ /clear
❯ in chunkindexservice, i m a bit bothered by the assymmertry of building the
shards in repairasync and flushrootasync. i would expect that there would
maybe be one method/one way that builds shards?
⏺ I'll explore the ChunkIndexService to understand how shards are built in both RepairAsync and FlushRootAsync.
⏺ Explore(Explore ChunkIndexService shard building) ⎿ Done (10 tool uses · 40.0k tokens · 56s) (ctrl+o to expand)
⏺ Let me read the actual code to understand the nuances precisely before designing.
Read 2 files (ctrl+o to expand)
⏺ Let me examine the local store to understand the range-read/count semantics that both paths depend on.
Read 1 file (ctrl+o to expand)
⏺ Let me verify the usages of the methods I'm considering unifying/removing, and check for any tests that reference them directly.
Searched for 2 patterns (ctrl+o to expand)
⏺ PartitionIntoLeaves is unit-tested directly in ChunkIndexRouterTests.cs. Let me read those tests and the flush/repair behavior tests to ground the design and the test-migration plan.
Searched for 1 pattern, read 1 file (ctrl+o to expand)
⏺ I now have a complete picture. Let me confirm the flush/repair tests are behavioral (so they survive a behavior-preserving refactor) and that only the two PartitionIntoLeaves unit tests are coupled to the helper I'd remove.
The flush tests (FlushAsync_ShardExceedsThreshold_SplitsIntoChildrenAndDeletesParent, ...SplitsRecursively, ..._InterruptedSplit..., ..._SplitOfEmptyRange_SkipsPostSplitListingAndDeletes, ..._Split_DeletesForeignStaleChildInRange) and repair tests (RepairAsync_RootOverThreshold_UploadsSplitLayout, RepairAsync_OverSplitRemoteLayout_CoarsensToFittingPrefix) all drive the public API and assert on resulting blobs — they pin the exact behavior I must preserve. Only the two PartitionIntoLeaves* router unit tests are coupled to the helper itself.
Let me write the plan.
⏺ Updated plan ⎿ /plan to preview
⏺ I've written the plan. Let me load and call the plan-exit tool to present it.
⎿ User rejected Claude's plan:
╭─────────────────────────────────────────────────────────────────────────╮
│ Unify shard building across RepairAsync and FlushRootAsync │
│ │
│ Context │
│ │
│ In ChunkIndexService, the same conceptual operation — "materialize the │
│ balanced set of leaf shards for a prefix range held in the local store, │
│ and upload them" — is implemented two different ways: │
│ │
│ - Flush (FlushRootAsync → SplitShardAsync, │
│ src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs:476-551): loads │
│ the whole range into one in-memory Shard via BuildShard, then │
│ partitions it in memory with ChunkIndexRouter.PartitionIntoLeaves │
│ (groups ShardEntrys by the next hex char, recursively), uploading each │
│ leaf. │
│ - Repair (RepairAsync, :699-734): computes the leaf prefixes by │
│ counting in SQLite with a recursive CollectLeaves local function │
│ (localStore.CountRangeEntries + ChunkIndexRouter.GetChildPrefixes), │
│ then loads and uploads each leaf via BuildShard + UploadShardAsync. │
│ │
│ Both produce the same balanced leaf partition (≤ MaxShardEntryCount per │
│ leaf, split 16-way, only non-empty leaves) and both upload via the │
│ same UploadShardAsync. So the sharding/partition algorithm exists │
│ twice, in two shapes. That duplication is the asymmetry. │
│ │
│ Goal: one leaf-planning algorithm and one build-and-upload routine, │
│ used by both paths. The genuinely-different orchestration — flush's │
│ gated, per-range, crash-safe stale cleanup vs. repair's single global │
│ stale-delete pass — stays in the respective callers, because those are │
│ different concerns, not "building shards." │
│ │
│ Approach │
│ │
│ Unify on the count-driven planner (repair's shape), because it │
│ preserves repair's deliberately memory-frugal design (never loads a │
│ whole root into memory — only one ≤1024-entry leaf at a time) and │
│ produces identical partitions. The re-read cost it adds to flush (one │
│ ranged SELECT per leaf + a few COUNTs, instead of one in-memory │
│ groupby) is negligible against the per-leaf blob uploads and only │
│ occurs on the rare split. │
│ │
│ 1. Router: replace PartitionIntoLeaves with a pure leaf planner │
│ │
│ In src/Arius.Core/Shared/ChunkIndex/ChunkIndexRouter.cs, remove │
│ PartitionIntoLeaves (:77-102) and add a count-probe-driven planner │
│ (keeps GetChildPrefixes, which it now also uses): │
│ │
│ ///
⏺ The user wants a different shape: a channel-decoupled producer/consumer (build shards → channel → upload), readable code (keeping the flush-style in-memory partition they already understand), plus a real memory-profile analysis up to ~1M chunks. Let me ground the memory math in the actual types.
Read 1 file (ctrl+o to expand)
⏺ Bash(fd -e cs 'ContentHash|ChunkHash|Hash' src/Arius.Core/Shared | head -40; echo "---SHARDENTRY---"; rg -l "record ShardEntry|class ShardEntry|readonly.*ContentHash…) ⎿ src/Arius.Core/Shared/Hashes/ChunkHash.cs src/Arius.Core/Shared/Hashes/ContentHash.cs src/Arius.Core/Shared/Hashes/FileTreeHash.cs … +8 lines (ctrl+o to expand)
⏺ Let me read the hash types to size a ShardEntry accurately.
Read 3 files (ctrl+o to expand) ⏺ Key finding for the memory analysis: ContentHash/ChunkHash are readonly record struct wrapping a 64-char hex string, not a packed 32-byte digest. So each holds a string reference (~152 B for a 64-char .NET string). Let me confirm the remaining dead-code surface before finalizing.
Searched for 1 pattern (ctrl+o to expand)
⏺ Channels are already used across the codebase, with shared helpers (ChannelReaderExtensions, AsyncEnumerableExtensions). Let me read the established idiom so the new code reuses it rather than reinventing the producer/consumer plumbing.
Read 2 files (ctrl+o to expand)
⏺ This is the key discovery: the codebase already has a canonical bounded producer/consumer idiom — AsyncEnumerableExtensions.WhereParallelAsync (bounded channel + linked CTS + producer Task that Complete(ex)s on fault + finally { cancel; await producer }). I'll mirror it exactly so the new code reads like existing code. And channels are clearly an established pattern here.
Now I have everything to ground the memory analysis and rewrite the plan around the channel design.
⏺ Updated plan ⎿ /plan to preview
⏺ Done. I reworked the plan around your feedback. Key points:
Memory profile (~1M chunks) — investigated, grounded in the actual types
ContentHash/ChunkHash wrap a 64-char hex string (not a 32-byte digest), so a ShardEntry in a Shard costs ~400 B (object ~56 B + two ~152 B strings + dict slot). Implications:
- Materializing everything ≈ 400 MB — and so would collecting all ~4096 leaf shards into a list before upload. Streaming is mandatory; the channel is the right call.
- With the bounded channel (capacity 32), peak ≈ 8–20 MB at 1M, broken down as: producer holds one root's Shard (~1.5 MB = 1M/256) + channel buffer (~3 MB) + 32 consumers in-flight (~3–16 MB). Only the single-root producer load grows with size (10M→~15 MB, 100M→~150 MB); the rest is flat.
- Honest caveats: repair's real memory hog is the pre-existing pendingThin listing buffer (hundreds of MB at 1M small files), which this change doesn't touch; and the 2-strings-per-entry layout is itself ~4–5× heavier than a digest representation would be (separate, bigger change — flagged, not done).
Design (readable, one way, channel-decoupled)
- Keep PartitionIntoLeaves unchanged (the in-memory flush-style split you already understand) — and its tests.
- BuildLeafShards(basePrefix) is the single shard-builder: build the range, emit it whole if it fits, else emit the split leaves.
- BuildAndUploadShardsAsync(...) is the single pipeline: one producer builds shards into a bounded channel, FlushWorkers consumers upload. It mirrors the codebase's existing AsyncEnumerableExtensions.WhereParallelAsync idiom (bounded channel + linked CTS + Writer.Complete(ex) + finally { cancel; await producer }), so it reads like existing code rather than a new invention.
- Both callers shrink to: call the pipeline, then their own cleanup. Flush keeps its crash-safe per-range stale delete (renamed DeleteStaleShardsAfterSplitAsync, upload half removed); repair keeps its global stale-delete pass.
- This deletes SplitShardAsync, repair's CollectLeaves, and the now-dead GetChildPrefixes + CountRangeEntries (count-driven path gone entirely).
Behavior is preserved exactly — the flush/repair behavior tests (split, recursive, interrupted-split, empty-range-skip, foreign-stale-child, repair split/coarsen) are the regression guard and stay untouched.
⏺ User approved Claude's plan ⎿ Plan saved to: ~/.claude/plans/in-chunkindexservice-i-m-linear-rivest.md · /plan to edit Unify shard building behind one channel-decoupled producer/consumer
Context
In ChunkIndexService the same operation — materialize the balanced leaf
shards for a prefix range held in the local store, and upload them — is
implemented twice, differently:
- Flush (FlushRootAsync → SplitShardAsync, ChunkIndexService.cs:476-551):
BuildShard(prefix) loads the range into one in-memory Shard, then
ChunkIndexRouter.PartitionIntoLeaves splits it in memory, uploading each
leaf.
- Repair (RepairAsync, :699-734): a recursive CollectLeaves local fn
computes leaf prefixes by counting in SQLite (CountRangeEntries +
GetChildPrefixes), then BuildShard + UploadShardAsync per leaf.
Both yield the identical balanced partition and both upload via
UploadShardAsync. The duplication (two partition algorithms, two upload
loops) is the asymmetry.
Goal (per feedback): one readable shard-builder (keep the flush-style
in-memory split everyone understands), with upload decoupled from
construction through a bounded channel — a single producer builds shards, N
consumers upload. The genuinely-different orchestration (flush's gated,
crash-safe per-range stale cleanup vs. repair's one global stale-delete
pass) stays in the callers.
This reuses the codebase's existing bounded producer/consumer idiom —
AsyncEnumerableExtensions.WhereParallelAsync
(src/Arius.Core/Shared/Extensions/AsyncEnumerableExtensions.cs): bounded
channel + linked CancellationTokenSource + producer Task that
Writer.Complete(ex)s on fault + finally { cts.Cancel(); await producer; }.
The new helper mirrors it.
Memory profile up to ~1M chunks (investigation)
Grounded in the actual types: ContentHash/ChunkHash are readonly record
struct wrapping a 64-char hex string (not a packed 32-byte digest), and
ShardEntry is a sealed record (Shard.cs:21, ContentHash.cs, ChunkHash.cs).
- A 64-char .NET string ≈ ~152 B. A ShardEntry object ≈ 56 B + its two hash
strings (distinct instances when read from the store via ReadEntry, even
for large chunks) ≈ ~360 B; inside a Shard's
Dictionary<ContentHash,ShardEntry> add ~32 B/slot → ~400 B per entry.
- Treating "1M chunks" as ~1M shard entries: materializing all entries at
once ≈ 400 MB — so we must never build the whole index, nor collect all
~4096 leaf shards into a list before uploading (also ≈ 400 MB). Streaming
is mandatory.
Bounded peak with the channel design (capacity = FlushWorkers = 32):
┌──────────────────────────────┬───────────────────┬──────────────────────┐
│ Term │ At 1M │ Scales with │
├──────────────────────────────┼───────────────────┼──────────────────────┤
│ Producer: one root's Shard │ ~1.5 MB (1M/256 │ total ÷ 256 │
│ (BuildShard(root)) │ roots × 400 B) │ │
├──────────────────────────────┼───────────────────┼──────────────────────┤
│ Channel buffer: 32 leaf │ ~3 MB (≤13 MB if │ │
│ shards │ leaves full at │ constant │
│ │ 1024) │ │
├──────────────────────────────┼───────────────────┼──────────────────────┤
│ Consumers: 32 × (leaf shard │ ~3–16 MB │ constant │
│ + serialized bytes) │ │ │
├──────────────────────────────┼───────────────────┼──────────────────────┤
│ │ │ only producer's │
│ Peak │ ~8–20 MB │ single-root load │
│ │ │ grows │
└──────────────────────────────┴───────────────────┴──────────────────────┘
So the phase this change touches is bounded to ~tens of MB at 1M and stays
flat except the producer's single-root load (10M → ~15 MB, 100M → ~150 MB;
repair is a rare admin op, 100M is far past scope). Current repair's upload
phase is already ~13 MB (32 workers × one leaf), so the added single-root
load is negligible at 1M.
Honest caveats (out of scope, flagged):
- Repair's dominant memory term is not this phase — it's the pre-existing
pendingThin buffer during the chunk listing (:637,691), which holds up to
all small-file entries (~hundreds of MB at 1M small files). This change
neither helps nor harms it.
- The 2-strings-per-entry layout makes in-memory shards ~4–5× larger than a
32-byte-digest representation would. Reworking ContentHash/ChunkHash to
store digests is a separate, larger change — noted, not done here.
- Verification includes an optional empirical check to confirm the
~tens-of-MB bound.
Design
1. Keep PartitionIntoLeaves as-is — the single in-memory split
No change to ChunkIndexRouter.PartitionIntoLeaves (:82-102) or its unit
tests. It remains the one partition algorithm, now used only by the
producer below. (It is only ever called on an over-threshold range,
matching its existing always-descend contract.)
2. One shard-builder
In ChunkIndexService.cs, next to BuildShard/UploadShardAsync:
/// <summary>
/// Builds the balanced leaf shards for one base prefix from local store
state: a single shard at the
/// base when its range fits the threshold, otherwise the non-empty leaves
of an in-memory 16-way split.
/// </summary>
private IEnumerable<(PathSegment Prefix, Shard Shard)>
BuildLeafShards(PathSegment basePrefix)
{
var shard = BuildShard(basePrefix);
if (shard.Count == 0)
yield break;
if (shard.Count <= _maxShardEntryCount)
{
yield return (basePrefix, shard);
yield break;
}
foreach (var leaf in ChunkIndexRouter.PartitionIntoLeaves(basePrefix,
shard.Entries.ToList(), _maxShardEntryCount))
{
var leafShard = new Shard();
leafShard.AddOrUpdateRange(leaf.Entries); // shares the same
immutable ShardEntry instances — no entry copy
yield return (leaf.Prefix, leafShard);
}
}
3. One channel-decoupled build-and-upload (mirrors WhereParallelAsync)
/// <summary>
/// Builds the balanced leaf shards for the given base prefixes and uploads
them, recording each
/// prefix→etag in <paramref name="uploadedStates"/>. A single producer
constructs shards (sequential
/// local-store reads) into a bounded channel; FlushWorkers consumers
upload them (parallel network I/O).
/// The bound caps resident shards at ~FlushWorkers regardless of
repository size. Returns the uploaded leaf prefixes.
/// </summary>
private async Task<IReadOnlyList<PathSegment>> BuildAndUploadShardsAsync(
IReadOnlyList<PathSegment> basePrefixes,
ConcurrentDictionary<PathSegment, string> uploadedStates,
CancellationToken cancellationToken)
{
var shards = Channel.CreateBounded<(PathSegment Prefix, Shard
Shard)>(
new BoundedChannelOptions(FlushWorkers) { SingleWriter = true,
SingleReader = false });
var uploaded = new ConcurrentBag<PathSegment>();
using var cts =
CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
var producer = Task.Run(async () =>
{
try
{
foreach (var basePrefix in basePrefixes)
foreach (var leaf in BuildLeafShards(basePrefix))
await shards.Writer.WriteAsync(leaf, cts.Token);
shards.Writer.Complete();
}
catch (Exception ex)
{
shards.Writer.Complete(ex);
}
}, CancellationToken.None);
try
{
await Parallel.ForEachAsync(
shards.Reader.ReadAllAsync(cts.Token),
new ParallelOptions { MaxDegreeOfParallelism = FlushWorkers,
CancellationToken = cts.Token },
async (leaf, ct) =>
{
var result = await UploadShardAsync(leaf.Prefix,
leaf.Shard, ct);
uploadedStates[leaf.Prefix] = result.ETag;
uploaded.Add(leaf.Prefix);
});
}
finally
{
await cts.CancelAsync(); // unblock the producer if a consumer
faulted/ended early
await producer; // observe producer completion/fault
(faults arrive via Writer.Complete(ex))
}
return uploaded.ToList();
}
Needs using System.Threading.Channels;.
4. FlushRootAsync: build+upload, then clean up only split targets
Replace the loop (:476-491); cleanup stays flush-specific and crash-safe
(all leaves land before any delete, because the pipeline drains before this
loop):
var targets = flushTargets.ToList();
var leafPrefixes = await BuildAndUploadShardsAsync(targets, uploadedStates,
cancellationToken);
foreach (var target in targets)
{
// Targets are pairwise non-nested, so each uploaded leaf maps to
exactly one target.
var written = leafPrefixes.Where(p =>
p.ToString().StartsWith(target.ToString(),
StringComparison.Ordinal)).ToList();
if (written.Count == 0 || (written.Count == 1 && written[0] == target))
continue; // empty range, or fit at the target → nothing stale to
clean
_logger.LogInformation("Split shard {Prefix} into {LeafCount} leaves",
target, written.Count);
await DeleteStaleShardsAfterSplitAsync(root, target, written,
cancellationToken);
}
Rename SplitShardAsync → DeleteStaleShardsAfterSplitAsync(root, prefix,
writtenLeaves, ct) and drop its upload half (:514-529), keeping its tail
verbatim: the run-scoped-listing rangeWasEmpty short-circuit (:508-534) and
the fresh-subtree-list + concurrent stale-delete (:536-550), with written
= writtenLeaves.Select(p => p.ToString()).
Behavior is preserved exactly: written == [target] ⇔ old count ≤ max
direct-upload (no cleanup); deeper written ⇔ old split branch (cleanup,
still skipped when the range was empty); empty range ⇔ old count == 0 skip.
5. RepairAsync: same pipeline + existing global stale-delete
Replace CollectLeaves + the manual upload Parallel.ForEachAsync (:699-734)
with:
var uploadedStates = new ConcurrentDictionary<PathSegment, string>();
var rebuiltPrefixes = (await BuildAndUploadShardsAsync(
_localStore.GetStoredRootPrefixes().ToList(), uploadedStates,
cancellationToken)).ToHashSet();
var uploadedShardCount = rebuiltPrefixes.Count;
The existing stale-delete pass (:736-749) and ChunkIndexRepairResult (:754)
are unchanged (rebuiltPrefixes.Count == uploadedShardCount under repair's
single-writer, as before).
6. Remove now-dead code
- ChunkIndexService.SplitShardAsync (folded into producer split +
DeleteStaleShardsAfterSplitAsync).
- RepairAsync's CollectLeaves local fn.
- ChunkIndexRouter.GetChildPrefixes (:115-121) — only CollectLeaves used
it; no test references it.
- ChunkIndexLocalStore.CountRangeEntries (:323-341) — only CollectLeaves
used it; remove its test assertions in
ChunkIndexLocalStoreTests.cs:314-316.
7. Tests
- Unchanged: ChunkIndexRouterTests PartitionIntoLeaves_*; all
ChunkIndexServiceFlushTests / ChunkIndexServiceRepairTests (split,
recursive split, interrupted-split crash safety, empty-range skip,
foreign-stale-child delete, repair split layout, over-split coarsening) —
behavioral, and the behavior is preserved.
- Remove: the CountRangeEntries assertions
(ChunkIndexLocalStoreTests.cs:314-316; drop the test if it becomes empty).
- Optional add: a memory check — stage ~1M synthetic entries in a local
store, run BuildAndUploadShardsAsync against a no-op fake
IBlobContainerService, and assert peak managed memory (GC.GetTotalMemory
sampling) stays within a low-tens-of-MB bound, confirming the analysis.
Verification
1. Build (Core internals change; build the whole solution per convention):
dotnet build Arius.sln
2. Partition unchanged: dotnet run --project src/Arius.Core.Tests --
--treenode-filter "/*/*/ChunkIndexRouterTests/*"
3. Behavior preserved (no Azure; the real regression guard):
dotnet run --project src/Arius.Core.Tests -- --treenode-filter
"/*/*/ChunkIndexServiceFlushTests/*"
dotnet run --project src/Arius.Core.Tests -- --treenode-filter
"/*/*/ChunkIndexServiceRepairTests/*"
dotnet run --project src/Arius.Core.Tests -- --treenode-filter
"/*/*/ChunkIndexLocalStoreTests/*"
4. Optionally run the memory-bound check (item 7) and the full
Arius.Core.Tests ChunkIndex namespace. (Azure-backed
Arius.Integration.Tests need ARIUS_* creds — out of scope locally.)
Net result
BuildLeafShards (readable, flush-style, keeps PartitionIntoLeaves) is the
one shard-builder; BuildAndUploadShardsAsync is the one channel-decoupled
upload pipeline (the codebase's existing idiom). Flush adds only its
crash-safe per-range cleanup; repair adds only its global stale-delete.
Construction is decoupled from upload, and peak memory is bounded (~tens of
MB at 1M chunks).
⏺ Plan approved. Let me implement it. First, let me look at the CountRangeEntries test I need to remove, then make all the edits.
Read 1 file (ctrl+o to expand)
⏺ Now I'll make all the edits. Starting with ChunkIndexService.cs — the using, the FlushRootAsync loop, the SplitShardAsync → cleanup rename, the new builder/pipeline methods, and the RepairAsync block.
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 1 line
1 using System.Collections.Concurrent;
2 using System.Collections.Frozen;
3 +using System.Threading.Channels;
4 using Arius.Core.Shared.Compression;
5 using Arius.Core.Shared.Encryption;
6 using Arius.Core.Shared.Snapshot;
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 13 lines, removed 12 lines
474 .Where(prefix => !distinctTargets.Any(other =>
other != prefix && prefix.ToString().StartsWith(other.ToStrin
g(), StringComparison.Ordinal)))
475 .OrderBy(prefix => prefix.ToString(), StringCo
mparer.Ordinal);
476
477 - foreach (var prefix in flushTargets)
477 + // Build and upload every target's leaf shards thr
+ough the shared producer/consumer pipeline.
478 + var targets = flushTargets.ToList();
479 + var leafPrefixes = await BuildAndUploadShardsAsync
+(targets, uploadedStates, cancellationToken);
480 +
481 + // A target whose range overflowed was split into
+deeper leaves, leaving a now-stale parent
482 + // (and any interrupted-split leftovers) behind; d
+elete them only after the leaves have landed,
483 + // so a crash mid-split keeps parent-wins lookup c
+orrect. A target that fit needs no cleanup.
484 + foreach (var target in targets)
485 {
479 - var shard = BuildShard(prefix);
480 - if (shard.Count == 0)
486 + // Targets are pairwise non-nested, so each up
+loaded leaf maps to exactly one target.
487 + var written = leafPrefixes.Where(prefix => pre
+fix.ToString().StartsWith(target.ToString(), StringComparison.
+Ordinal)).ToList();
488 + if (written.Count == 0 || (written.Count == 1
+&& written[0] == target))
489 continue;
490
483 - if (shard.Count <= _maxShardEntryCount)
484 - {
485 - var result = await UploadShardAsync(prefix
-, shard, cancellationToken);
486 - uploadedStates[prefix] = result.ETag;
487 - _logger.LogDebug("Uploaded shard {Prefix}
-({EntryCount} entries)", prefix, shard.Count);
488 - continue;
489 - }
490 -
491 - await SplitShardAsync(root, prefix, shard, upl
-oadedStates, cancellationToken);
491 + _logger.LogInformation("Split shard {Prefix} i
+nto {LeafCount} leaves", target, written.Count);
492 + await DeleteStaleShardsAfterSplitAsync(root, t
+arget, written, cancellationToken);
493 }
494 }
495 finally
⏺ Now replace SplitShardAsync with the cleanup-only DeleteStaleShardsAfterSplitAsync:
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 9 lines, removed 29 lines
499 }
500
501 ///
503 - /// deletes the parent and any other stale shard in its ra
-nge. A crash mid-split leaves the
504 - /// parent intact; since the snapshot for this run is not
-yet published, the parent still
505 - /// contains everything any published snapshot references,
- and parent-wins lookup stays
506 - /// correct. The pending rows stay pending, so a retry re-
-resolves the parent and re-splits.
502 + /// After a split's leaf shards have all landed, deletes t
+he now-stale parent and any other blob in
503 + /// range(prefix) that was not just written — including le
+ftovers of a previously interrupted split.
504 + /// Uploading the leaves before this delete keeps parent-w
+ins lookup correct if a crash interrupts the
505 + /// split: the parent stays intact, and since this run's s
+napshot is not yet published it still contains
506 + /// everything any published snapshot references. The pend
+ing rows stay pending, so a retry re-splits.
507 ///
508 + private async Task DeleteStaleShardsAfterSplitAsync(PathSe
+gment root, PathSegment prefix, IReadOnlyList
509 {
510 // Whether range(prefix) held any remote shard before
this run's flush. Under the single-writer
511 - // assumption the run-scoped listing is that pre-flush
- state (our own leaf uploads below never
512 - // appear in the immutable snapshot), so an empty rang
-e means there is nothing stale to clean.
511 + // assumption the run-scoped listing is that pre-flush
+ state (our own leaf uploads never appear in
512 + // the immutable snapshot), so an empty range means th
+ere is nothing stale to clean.
513 var rangeWasEmpty = !((await _shardListing.GetAsync(ca
ncellationToken)).GetValueOrDefault(root.ToString()) ?? Frozen
Dictionary
516 - var leaves = ChunkIndexRouter.PartitionIntoLeaves(pref
-ix, shard.Entries.ToList(), _maxShardEntryCount);
517 -
518 - // Upload the (independent) leaf shards concurrently.
-ALL must land before any delete: a crash
519 - // mid-split must leave the parent intact so parent-wi
-ns lookup stays correct.
520 - await Parallel.ForEachAsync(
521 - leaves,
522 - new ParallelOptions { MaxDegreeOfParallelism = Flu
-shWorkers, CancellationToken = cancellationToken },
523 - async (leaf, ct) =>
524 - {
525 - var leafShard = new Shard();
526 - leafShard.AddOrUpdateRange(leaf.Entries);
527 - var result = await UploadShardAsync(leaf.Prefi
-x, leafShard, ct);
528 - uploadedStates[leaf.Prefix] = result.ETag;
529 - });
530 -
531 - _logger.LogInformation("Split shard {Prefix} ({EntryCo
-unt} entries) into {LeafCount} leaves", prefix, shard.Count, l
-eaves.Count);
532 -
533 - // A brand-new (empty) range had no parent or interrup
-ted-split leftovers, so the post-split
534 - // subtree listing and deletes are pure waste — skip t
-hem.
515 if (rangeWasEmpty)
516 return;
517
...
519 // including leftovers of a previously interrupted spl
it (their extra entries were never
520 // published; the machine that wrote them still has th
em as pending rows and will re-flush).
521 // The destructive scan reads fresh remote state; dele
tes run concurrently.
542 - var written = leaves.Select(leaf => leaf.Prefix.ToStri
-ng()).ToHashSet(StringComparer.Ordinal);
522 + var written = writtenLeaves.Select(leaf => leaf.ToStri
+ng()).ToHashSet(StringComparer.Ordinal);
523 var listing = await ListShardSubtreeAsync(root, cancel
lationToken);
524 var stale = listing.Where(name => name.StartsWith(pref
ix.ToString(), StringComparison.Ordinal) && !written.Contains(
name)).ToList();
525 await Parallel.ForEachAsync(
⏺ Now insert BuildLeafShards and BuildAndUploadShardsAsync after UploadShardAsync:
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 77 lines
564 cancellationToken: cancellationToken);
565 }
566
567 + ///
568 + /// Builds the balanced leaf shards for one base prefix fr
+om local store state: a single shard at the
569 + /// base when its range fits the threshold, otherwise the
+non-empty leaves of an in-memory 16-way split.
570 + ///
571 + private IEnumerable<(PathSegment Prefix, Shard Shard)> Bui
+ldLeafShards(PathSegment basePrefix)
572 + {
573 + var shard = BuildShard(basePrefix);
574 + if (shard.Count == 0)
575 + yield break;
576 +
577 + if (shard.Count <= _maxShardEntryCount)
578 + {
579 + yield return (basePrefix, shard);
580 + yield break;
581 + }
582 +
583 + foreach (var leaf in ChunkIndexRouter.PartitionIntoLea
+ves(basePrefix, shard.Entries.ToList(), _maxShardEntryCount))
584 + {
585 + var leafShard = new Shard();
586 + leafShard.AddOrUpdateRange(leaf.Entries); // share
+s the same immutable ShardEntry instances — no entry copy
587 + yield return (leaf.Prefix, leafShard);
588 + }
589 + }
590 +
591 + ///
592 + /// Builds the balanced leaf shards for the given base pre
+fixes and uploads them, recording each
593 + /// prefix→etag in
594 + /// local-store reads) into a bounded channel;
595 + /// network I/O). The bound caps resident shards at ~
596 + /// size. Returns the uploaded leaf prefixes.
597 + ///
598 + private async Task
599 + IReadOnlyList
600 + ConcurrentDictionary
601 + CancellationToken cancellationToken)
602 + {
603 + var shards = Channel.CreateBounded<(PathSegment Pref
+ix, Shard Shard)>(
604 + new BoundedChannelOptions(FlushWorkers) { SingleWr
+iter = true, SingleReader = false });
605 + var uploaded = new ConcurrentBag
606 + using var cts = CancellationTokenSource.CreateLinkedTo
+kenSource(cancellationToken);
607 +
608 + var producer = Task.Run(async () =>
609 + {
610 + try
611 + {
612 + foreach (var basePrefix in basePrefixes)
613 + foreach (var leaf in BuildLeafShards(baseP
+refix))
614 + await shards.Writer.WriteAsync(leaf, c
+ts.Token);
615 + shards.Writer.Complete();
616 + }
617 + catch (Exception ex)
618 + {
619 + shards.Writer.Complete(ex);
620 + }
621 + }, CancellationToken.None);
622 +
623 + try
624 + {
625 + await Parallel.ForEachAsync(
626 + shards.Reader.ReadAllAsync(cts.Token),
627 + new ParallelOptions { MaxDegreeOfParallelism =
+ FlushWorkers, CancellationToken = cts.Token },
628 + async (leaf, ct) =>
629 + {
630 + var result = await UploadShardAsync(leaf.P
+refix, leaf.Shard, ct);
631 + uploadedStates[leaf.Prefix] = result.ETag;
632 + uploaded.Add(leaf.Prefix);
633 + });
634 + }
635 + finally
636 + {
637 + await cts.CancelAsync(); // unblock the producer i
+f a consumer faulted or ended early
638 + await producer; // observe producer compl
+etion/fault (faults arrive via Writer.Complete(ex))
639 + }
640 +
641 + return uploaded.ToList();
642 + }
643 +
644 // -- Stats ----------------------------------------------
-----------------
645
646 ///
⏺ Now the RepairAsync block — replace CollectLeaves + the manual upload loop:
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 6 lines, removed 36 lines
755 }
756 FlushStaged();
757
758 - // Compute a fresh balanced layout from the staged ent
-ries: recursively split any range
759 - // whose entry count exceeds the threshold. This also
-re-balances an over-split remote
760 - // layout (the stale-shard pass below deletes everythi
-ng not in the rebuilt set).
761 - var rebuiltPrefixes = new HashSet
762 - foreach (var root in _localStore.GetStoredRootPrefixes
-())
763 - CollectLeaves(root);
758 + // Build and upload a fresh balanced layout from the s
+taged entries through the shared
759 + // producer/consumer pipeline. This also re-balances a
+n over-split remote layout (the
760 + // stale-shard pass below deletes everything not in th
+e rebuilt set).
761 + var uploadedStates = new ConcurrentDictionary
762 + var rebuiltPrefixes = (await BuildAndUploadShardsAsync
+(_localStore.GetStoredRootPrefixes().ToList(), uploadedStates,
+ cancellationToken)).ToHashSet();
763 + var uploadedShardCount = rebuiltPrefixes.Count;
764
765 - void CollectLeaves(PathSegment prefix)
766 - {
767 - var count = _localStore.CountRangeEntries(prefix);
768 - if (count == 0)
769 - return;
770 -
771 - if (count <= _maxShardEntryCount)
772 - {
773 - rebuiltPrefixes.Add(prefix);
774 - return;
775 - }
776 -
777 - foreach (var child in ChunkIndexRouter.GetChildPre
-fixes(prefix))
778 - CollectLeaves(child);
779 - }
780 -
781 - var uploadedShardCount = 0;
782 - await Parallel.ForEachAsync(
783 - rebuiltPrefixes,
784 - new ParallelOptions { MaxDegreeOfParallelism = Flu
-shWorkers, CancellationToken = cancellationToken },
785 - async (prefix, ct) =>
786 - {
787 - var shard = BuildShard(prefix);
788 - if (shard.Count == 0)
789 - return;
790 -
791 - await UploadShardAsync(prefix, shard, ct);
792 - Interlocked.Increment(ref uploadedShardCount);
793 - });
794 -
765 // Delete stale shards
766 var deletedStaleShardCount = 0;
767 await Parallel.ForEachAsync(
⏺ Now the router (remove GetChildPrefixes + the now-unused HexChars), the local store (CountRangeEntries), and the stale test assertions:
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexRouter.cs)
⎿ Removed 2 lines
15 ///
16 internal static class ChunkIndexRouter
17 {
18 - private const string HexChars = "0123456789abcdef";
19 -
18 ///
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexRouter.cs)
⎿ Removed 8 lines
109 var hex = prefix.ToString();
110 return (Convert.FromHexString(hex.PadRight(64, '0')),
Convert.FromHexString(hex.PadRight(64, 'f')));
111 }
112 -
113 - ///
114 - public static IEnumerable
115 - {
116 - var hex = prefix.ToString();
117 - foreach (var c in HexChars)
118 - yield return PathSegment.Parse(hex + c);
119 - }
112 }
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexLocalStore.cs)
⎿ Removed 23 lines
317 }
318 }
319
320 - ///
321 - /// Returns the number of entries currently stored within
-range of
322 - ///
323 - public int CountRangeEntries(PathSegment prefix)
324 - {
325 - try
326 - {
327 - var (lower, upper) = ChunkIndexRouter.GetHashRange
-Bounds(prefix);
328 - using var connection = OpenConnection();
329 - using var command = connection.CreateCommand();
330 - command.CommandText = "SELECT COUNT(*) FROM chunk_
-index_entries WHERE content_hash BETWEEN $lower AND $upper;";
331 - command.Parameters.Add("$lower", SqliteType.Blob).
-Value = lower;
332 - command.Parameters.Add("$upper", SqliteType.Blob).
-Value = upper;
333 - var count = Convert.ToInt32(command.ExecuteScalar(
-));
334 - _logger.LogDebug("[chunk-index-local] CountRangeEn
-tries: prefix={Prefix} count={Count}", prefix, count);
335 - return count;
336 - }
337 - catch (SqliteException ex)
338 - {
339 - throw CreateLocalStoreException(ex);
340 - }
341 - }
342 -
320 // -- STATISTICS -----------------------------------------
--------
321
322 ///
⏺ Update(src/Arius.Core.Tests/Shared/ChunkIndex/ChunkIndexLocalStoreTests.cs)
⎿ Removed 3 lines
311 store.ReadRangeEntries(PathSegment.Parse("aa3"), inRan
ge.Add);
312
313 inRange.Select(e => e.ContentHash).ShouldBe([entries[1
].ContentHash, entries[2].ContentHash]);
314 - store.CountRangeEntries(PathSegment.Parse("aa3")).Shou
-ldBe(2);
315 - store.CountRangeEntries(PathSegment.Parse("aa")).Shoul
-dBe(4);
316 - store.CountRangeEntries(PathSegment.Parse("bb")).Shoul
-dBe(0);
314 }
315
316 [Test]
⏺ Let me verify the modified FlushRootAsync, the new methods, and RepairAsync read correctly in context before building.
Read 1 file (ctrl+o to expand)
⏺ I spotted a name collision: targets is already declared at line 467 (the dictionary from EnsureCoverageCoreAsync). Let me fix it by materializing flushTargets into a list directly and using that name throughout.
⏺ Update(src/Arius.Core/Shared/ChunkIndex/ChunkIndexService.cs)
⎿ Added 4 lines, removed 4 lines
472 var distinctTargets = targets.Values.Distinct().To
List();
473 var flushTargets = distinctTargets
474 .Where(prefix => !distinctTargets.Any(other =>
other != prefix && prefix.ToString().StartsWith(other.ToStrin
g(), StringComparison.Ordinal)))
475 - .OrderBy(prefix => prefix.ToString(), StringCo
-mparer.Ordinal);
475 + .OrderBy(prefix => prefix.ToString(), StringCo
+mparer.Ordinal)
476 + .ToList();
477
478 // Build and upload every target's leaf shards thr
ough the shared producer/consumer pipeline.
478 - var targets = flushTargets.ToList();
479 - var leafPrefixes = await BuildAndUploadShardsAsync
-(targets, uploadedStates, cancellationToken);
479 + var leafPrefixes = await BuildAndUploadShardsAsync
+(flushTargets, uploadedStates, cancellationToken);
480
481 // A target whose range overflowed was split into
deeper leaves, leaving a now-stale parent
482 // (and any interrupted-split leftovers) behind; d
elete them only after the leaves have landed,
483 // so a crash mid-split keeps parent-wins lookup c
orrect. A target that fit needs no cleanup.
484 - foreach (var target in targets)
484 + foreach (var target in flushTargets)
485 {
486 // Targets are pairwise non-nested, so each up
loaded leaf maps to exactly one target.
487 var written = leafPrefixes.Where(prefix => pre
fix.ToString().StartsWith(target.ToString(), StringComparison.
Ordinal)).ToList();
⏺ Now let me build the affected projects (building the test project compiles Arius.Core transitively).
⏺ Bash(dotnet build src/Arius.Core.Tests/Arius.Core.Tests.csproj -v quiet --nologo 2>&1 | tail -40) ⎿ /Users/wouter/.superset/worktrees/Arius7/migrate-v5-v7-2/src/Arius.Cor e/Shared/Encryption/PassphraseEncryptionService.cs(611,38): warning SC S0013: Potential usage of weak CipherMode. (https://security-code-scan … +164 lines (ctrl+o to expand) ⎿ (timeout 5m)
⏺ The only error is an environment/tooling failure in CreateAppHost (IsMemberOfGroup overflow on macOS) for Arius.Tests.Shared — not a compile error in my code (Arius.Core produced only pre-existing warnings). Let me confirm Arius.Core itself compiles cleanly, and work around the apphost glitch.
⏺ Bash(dotnet build src/Arius.Core/Arius.Core.csproj -v quiet --nologo 2>&1 | grep -E "error|Build succeeded|[0-9]+ Error" | head -20; echo "=== exit: done ===") ⎿ Build succeeded. 0 Error(s) === exit: done ===
⏺ Arius.Core builds clean (0 errors). The apphost failure is a known macOS SDK glitch. Let me work around it with UseAppHost=false and build the test project.
⏺ Bash(dotnet build src/Arius.Core.Tests/Arius.Core.Tests.csproj -v quiet --nologo -p:UseAppHost=false 2>&1 | grep -E "error|Build succeeded|[0-9]+ Error" | head -20;…) ⎿ Build succeeded. 0 Error(s) === done ===
⏺ The test project builds clean too. Now run the ChunkIndex test suites — the partition unit tests, plus the flush/repair/local-store behavior tests that pin the behavior I preserved.
⏺ Bash(dotnet run --project src/Arius.Core.Tests --no-build -- --treenode-filter "///ChunkIndexRouterTests/*" 2>&1 | tail -25; echo "=== ROUTER done ===") ⎿ Unhandled exception: An error occurred trying to start process '/Users /wouter/.superset/worktrees/Arius7/migrate-v5-v7-2/src/Arius.Core.Test s/bin/Debug/net10.0/Arius.Core.Tests' with working directory '/Users/w … +3 lines (ctrl+o to expand)
⏺ dotnet run needs the apphost we skipped. I'll invoke the test DLL directly (MTP apps accept args directly).
⏺ Bash(dotnet src/Arius.Core.Tests/bin/Debug/net10.0/Arius.Core.Tests.dll --treenode-filter "///ChunkIndexRouterTests/*" 2>&1 | tail -25; echo "=== ROUTER done ===") ⎿ ████████╗██╗ ██╗███╗ ██╗██╗████████╗ ╚══██╔══╝██║ ██║████╗ ██║██║╚══██╔══╝ ██║ ██║ ██║██╔██╗ ██║██║ ██║ … +24 lines (ctrl+o to expand)
⏺ Router tests pass (9/9). Now the behavior-preserving suites — flush, repair, and local store:
⏺ Bash(cd /Users/wouter/.superset/worktrees/Arius7/migrate-v5-v7-2 for t in ChunkIndexServiceFlushTests ChunkIndexServiceRepairTests ChunkIndexLocalStoreTests; do…) ⎿ === ChunkIndexServiceFlushTests === Test run summary: Passed! - /Users/wouter/.superset/worktrees/Arius7/m igrate-v5-v7-2/src/Arius.Core.Tests/bin/Debug/net10.0/Arius.Core.Tests … +22 lines (ctrl+o to expand)
⏺ All green: router 9/9, flush 11/11, repair 10/10, local store 23/23. Let me run the remaining ChunkIndex suites (lookup, listing-cache, archive-scenario, shard) since they exercise the service end-to-end too.
⏺ Bash(cd /Users/wouter/.superset/worktrees/Arius7/migrate-v5-v7-2 for t in ChunkIndexServiceLookupTests ChunkIndexServiceListingCacheTests ChunkIndexServiceArchiveSce…) ⎿ === ChunkIndexServiceLookupTests === Test run summary: Passed! - /Users/wouter/.superset/worktrees/Arius7/m igrate-v5-v7-2/src/Arius.Core.Tests/bin/Debug/net10.0/Arius.Core.Tests … +23 lines (ctrl+o to expand)
⏺ All ChunkIndex suites pass — 112/112 across router, flush, repair, local store, lookup, listing-cache, archive-scenario, and shard. Let me run the full Arius.Core.Tests suite as a safety net to confirm nothing outside ChunkIndex regressed.
⏺ Bash(cd /Users/wouter/.superset/worktrees/Arius7/migrate-v5-v7-2 dotnet src/Arius.Core.Tests/bin/Debug/net10.0/Arius.Core.Tests.dll 2>&1 | grep -E "total:|failed:|su…) ⎿ Test run summary: Passed! - /Users/wouter/.superset/worktrees/Arius7/m igrate-v5-v7-2/src/Arius.Core.Tests/bin/Debug/net10.0/Arius.Core.Tests .dll (net10.0|arm64) … +6 lines (ctrl+o to expand)
⏺ Full suite green: 565 passed, 1 skipped (pre-existing), 0 failed in ~1.8s. The refactor is complete and verified.
Let me capture the working-preference signal from this session to memory.
Recalled 1 memory, wrote 2 memories (ctrl+o to expand)
⏺ Done. The asymmetry is gone — flush and repair now build shards exactly one way, with upload decoupled from construction through a bounded channel.
What changed
One shard-builder — BuildLeafShards(basePrefix): builds the range, emits it whole if it fits, else emits the in-memory split leaves. Keeps PartitionIntoLeaves (and its tests) — the readable flush-style split you already understood.
One upload pipeline — BuildAndUploadShardsAsync(basePrefixes, …): a single producer builds shards into a bounded channel; FlushWorkers consumers upload in parallel. It mirrors the codebase's existing WhereParallelAsync idiom (bounded channel + linked CTS + Writer.Complete(ex) on fault + finally { cancel; await producer }), so it reads like existing code.
Both callers shrank to: call the pipeline, then their own orchestration — - Flush keeps its crash-safe per-range cleanup (SplitShardAsync → DeleteStaleShardsAfterSplitAsync, upload half removed). - Repair keeps its global stale-delete pass.
Deleted the duplicated count-driven path entirely: SplitShardAsync, repair's CollectLeaves, ChunkIndexRouter.GetChildPrefixes (+ HexChars), and ChunkIndexLocalStore.CountRangeEntries (+ its test assertions).
Verification
- Arius.Core compiles clean (0 errors).
- Full Arius.Core.Tests: 565 passed, 1 skipped, 0 failed. The flush/repair behavior tests (split, recursive split, interrupted-split crash safety, empty-range skip, foreign-stale-child delete, repair split layout, over-split coarsening) — the real regression guard — all pass unchanged.
Two notes: - A macOS SDK glitch (CreateAppHost → IsMemberOfGroup overflow) blocks the apphost step for Arius.Tests.Shared; it's environmental, not from this change. I built with -p:UseAppHost=false and ran the test DLL directly. The changes are internal to Arius.Core (the removed public members live on internal classes with no other callers), so no downstream project is affected. - The memory bench (plan item 7) was optional and I left it unbuilt — the analysis stands on the bounded design (~tens of MB at 1M). Say the word if you want an empirical GC-sampling test to confirm it.
✻ Cooked for 31m 17s