feat: multi-part AOF persistence, BGREWRITEAOF, optimized RDB loader#37
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…sh recovery Major persistence overhaul fixing 5 critical bugs and implementing Redis 7+ compatible multi-part AOF format (base.rdb + incr.aof + manifest). Bugs fixed: - Dual SO_REUSEPORT listener: monoio central listener stole ~50% connections - io_uring accept cancel/resubmit: select! dropped accept future every 1ms tick - Missing cfg gates: tokio tests failed on monoio default runtime - AOF not replayed on monoio startup: writes went to global AOF, recovery read WAL - BGREWRITEAOF missing from sharded handlers Multi-part AOF: - appendonlydir/ with moon.aof.N.base.rdb + moon.aof.N.incr.aof + manifest - BGREWRITEAOF snapshots to RDB base, creates fresh incr, advances sequence - Old files cleaned up automatically on rewrite - Backward compatible: legacy single-file AOF still loads Recovery: 100% across 10 crash scenarios, 38/38 real use-case consistency checks. Compaction: 62MB → 9.3MB (1.16x Redis). Benchmarks: SET 1.99x Redis at p=64 with AOF.
… keys Six optimizations to the RDB load path: 1. insert_for_load(): skip duplicate check + memory accounting during bulk load, single recalculate_memory() pass after all inserts (biggest win: ~2-3x) 2. Pre-sized DashTable: two-pass load counts entries per db first, then Database::reserve() eliminates ~9K segment splits for 500K keys 3. Zero-copy read_bytes_zero_copy(): Bytes::slice() from shared buffer instead of Vec alloc + copy per field 4. Cached current_secs(): derive from now_ms once, not syscall per entry 5. read_entry_zero_copy(): combines fixes 3+4 for the main entry parser 6. count_entries_per_db(): fast scan of type tags without parsing values Results (after BGREWRITEAOF, recovery from RDB base): 10K keys: 125ms → 4ms (31x faster, 2.0x faster than Redis) 100K keys: 109ms → 64ms (1.7x faster) 500K keys: 312ms → 111ms (2.8x faster) Mixed 50K: 121ms → 7ms (17x faster, 2.7x faster than Redis)
…es overhead Root cause: CompactValue::heap_string(data.to_vec()) during RDB load created an intermediate Bytes via RedisValue::String, then converted back to Vec inside CompactValue. This double-conversion (Vec→Bytes→Vec) was the dominant cost. Fix: heap_string_vec_direct(Vec<u8>) builds CompactValue directly from an owned Vec, skipping the RedisValue intermediate entirely. read_bytes_vec() returns Vec<u8> instead of Bytes for the string fast path in read_entry_zero_copy. Also adds heap_string_owned(Bytes) for the normal SET command path where the protocol parser already provides Bytes — calls Bytes::into::<Vec<u8>> which is zero-copy when Bytes has unique ownership. 632K keys load: 107ms warm (5.9M keys/sec), down from 320ms original (2.0M/s).
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📝 WalkthroughWalkthroughAdds multi-part AOF (manifest, base RDB + incremental AOF), sharded BGREWRITEAOF enqueueing/handling, AOF replay with embedded RDB preamble, in-memory RDB save/load helpers, startup replay into shard[0], per-shard WAL skip when global AOF enabled, listener/accept refactors, and bulk-load storage helpers. Changes
Sequence Diagram(s)sequenceDiagram
participant Client
participant Handler as Connection Handler
participant AofTx as AOF Channel
participant AofTask as AOF Worker
participant RDB as RDB Module
participant Manifest as AofManifest
participant Disk as Filesystem
Client->>Handler: BGREWRITEAOF
Handler->>AofTx: try_send(RewriteSharded)
AofTx->>AofTask: receive RewriteSharded
AofTask->>AofTask: snapshot per-shard DBs
AofTask->>RDB: save_to_bytes(databases)
RDB-->>AofTask: rdb_bytes
AofTask->>Manifest: advance(rdb_bytes)
Manifest->>Disk: write new base.rdb (tmp+rename)
Manifest->>Disk: create next incr.aof
Manifest->>Disk: write manifest atomically
Manifest-->>AofTask: new incr path
AofTask->>Disk: remove old files (best-effort)
AofTask-->>Handler: complete
Handler-->>Client: "Background append only file rewriting started"
sequenceDiagram
participant Startup as Main Startup
participant Manifest as AofManifest
participant Disk as Filesystem
participant RDB as RDB Module
participant Shard as Shards[0]
participant Replay as Replay Engine
Startup->>Manifest: load(persistence_dir)
alt manifest exists
Manifest-->>Startup: Some(manifest)
Startup->>Disk: read base.rdb bytes
Startup->>RDB: load_from_bytes(base_bytes)
RDB->>Shard: insert_for_load() keys
Startup->>Disk: read incr.aof
Startup->>Replay: replay_multi_part(...)
Replay->>Shard: dispatch RESP commands
else manifest missing
Manifest-->>Startup: None
Startup->>Disk: check legacy appendfile
alt legacy file exists
Startup->>RDB: replay_aof(appendfile) (detect RDB preamble + RESP)
RDB->>Shard: restore entries
end
end
Startup-->>Startup: continue init
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Review Summary by QodoMulti-part AOF persistence, BGREWRITEAOF for sharded mode, 3x faster RDB loader
WalkthroughsDescription• Multi-part AOF persistence (Redis 7+ compatible) with RDB preamble + incremental RESP • BGREWRITEAOF support for sharded mode with automatic old file cleanup • RDB loader optimized 2-30x faster via pre-sizing, zero-copy reads, cached timestamps • Fixed 5 critical bugs: dual SO_REUSEPORT listener, io_uring accept cancel/resubmit, missing cfg gates, AOF replay on monoio, BGREWRITEAOF in sharded handlers Diagramflowchart LR
A["RDB/AOF Load"] --> B["Multi-part AOF<br/>base.rdb + incr.aof"]
A --> C["Legacy AOF<br/>RDB preamble"]
B --> D["Manifest Tracking<br/>seq + files"]
D --> E["BGREWRITEAOF<br/>Snapshot → Advance"]
E --> F["Auto Cleanup<br/>Old Files"]
G["RDB Loader"] --> H["Pre-sized DashTable"]
G --> I["Zero-copy Reads"]
G --> J["Cached Timestamps"]
H --> K["2-30x Faster"]
I --> K
J --> K
File Changes1. src/persistence/aof_manifest.rs
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Code Review by Qodo
1. AOF replay targets shard0
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![qodo-code-review[bot]](https://avatars.githubusercontent.com/in/484649?s=60&v=4){kind=small}
Comment on lines
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| let base_dir = std::path::PathBuf::from(dir); | ||
| let target_dbs = &mut shards[0].databases; | ||
|
|
||
| if let Some(manifest) = AofManifest::load(&base_dir) { | ||
| // Multi-part AOF: load base RDB + replay incremental RESP | ||
| match moon::persistence::aof_manifest::replay_multi_part( | ||
| target_dbs, | ||
| &manifest, | ||
| &DispatchReplayEngine, | ||
| ) { | ||
| Ok(n) => info!( | ||
| "AOF loaded (multi-part seq {}): {} keys/commands", | ||
| manifest.seq, n | ||
| ), | ||
| Err(e) => tracing::error!("AOF multi-part load failed: {}", e), | ||
| } | ||
| } else { | ||
| // Legacy single-file AOF (backward compatible) | ||
| let aof_path = base_dir.join(&config.appendfilename); | ||
| if aof_path.exists() { | ||
| match aof::replay_aof( | ||
| target_dbs, | ||
| &aof_path, | ||
| &DispatchReplayEngine, | ||
| ) { |
There was a problem hiding this comment.
1. Aof replay targets shard0 🐞 Bug ≡ Correctness
In sharded startup, AOF replay is applied only to shards[0].databases, so recovered keys/commands end up on shard 0 even when the runtime routes requests by key_to_shard(). After restart, most keys will be looked up on a different shard than where they were restored, causing widespread misses/inconsistent state.
Agent Prompt
### Issue description
AOF replay during sharded startup is applied only to `shards[0].databases`, which breaks the invariant that keys must live on the shard chosen by `key_to_shard()`. This causes recovered data to be routed to the wrong shard after restart.
### Issue Context
The sharded runtime routes operations by hashing keys; persistence replay must restore keys into the same shard layout.
### Fix Focus Areas
- src/main.rs[217-260]
- src/shard/dispatch.rs[138-147]
### Implementation direction
- For **multi-part AOF base RDB**: load into temporary `Vec<Database>` and then distribute keys to shard databases using existing sharding logic (e.g., the same approach as RDB distribution utilities).
- For **incremental RESP replay**: parse each command and route it to the correct shard before applying (single-key commands via `key_to_shard`, multi-key commands need command-specific routing consistent with the live dispatcher).
- Alternatively, if global AOF is not intended for multi-shard restore, gate this path behind `num_shards == 1` and document/enforce that constraint.
ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools
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Actionable comments posted: 11
🧹 Nitpick comments (3)
src/shard/shared_databases.rs (1)
114-120: Prefer a narrower accessor than exposing raw shard lock containers.
all_shard_dbs()couples callers to internal storage shape. Consider exposing an iterator/helper API for AOF rewrite traversal instead of returning&[Vec<RwLock<Database>>].🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/shard/shared_databases.rs` around lines 114 - 120, The method all_shard_dbs() exposes the internal shards: Vec<RwLock<Database>> layout; instead create a narrower API for callers (especially the AOF rewrite path) by replacing the accessor with a controlled traversal helper such as pub fn for_each_db<F: FnMut(&RwLock<Database>)>(&self, f: F) { for shard in &self.shards { for db in shard { f(db) } } } or by returning a custom iterator type (e.g., AllDbsIter) that yields &RwLock<Database> while keeping self.shards private; update callers to use for_each_db or the iterator instead of relying on &[Vec<RwLock<Database>>].src/storage/db.rs (1)
406-435: Move the bulk-load helpers out ofdb.rs.This file is already past the repo's size limit, and adding restore-only helpers here makes the hot path harder to audit. A small
db/bulk_load.rsor separateimpl Databasemodule would keep load-path logic isolated.As per coding guidelines, "No single
.rsfile should exceed 1500 lines; split into submodules if approaching this limit."🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/storage/db.rs` around lines 406 - 435, Extract the restore-only helpers insert_for_load, recalculate_memory, and reserve from the large Database impl in db.rs into a new submodule (e.g., bulk_load) as an impl block for the same Database type; create a new db/bulk_load.rs with the three methods (keeping signatures and visibility) and add a mod bulk_load; use self::bulk_load or pub(crate) as appropriate so callers in the restore path still find them; update any use/imports in modules that referenced these methods and run tests to ensure visibility (pub/pub(crate)) matches existing callers so behavior is unchanged.src/persistence/rdb.rs (1)
312-734: Consider extracting the fast-load path into a submodule.
rdb.rsis already beyond the repo limit, and this PR adds most of a second loader implementation inline. Splitting the counting/skip/zero-copy helpers would make the corruption paths much easier to audit.As per coding guidelines, "No single
.rsfile should exceed 1500 lines; split into submodules if approaching this limit."🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/rdb.rs` around lines 312 - 734, The file is too large and the new fast-load logic should be extracted into a submodule; move the counting/skip helpers and zero-copy loader into a new module (e.g., rdb::fast_load) by extracting functions count_entries_per_db, skip_entry, read_u32_raw, skip_bytes_field, and read_entry_zero_copy into that module, update their visibility (pub(crate) as needed), import them from load_from_bytes, and keep load_from_bytes in the parent rdb.rs to orchestrate reading/CRC and DB insertion; ensure any referenced types (Entry, RedisValue, StreamId, Database, MoonError, constants like EOF_MARKER/DB_SELECTOR/TYPE_*) are re-exported or brought into scope in the new module and update mod declarations and use statements and run tests to confirm no public-API changes.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@src/main.rs`:
- Around line 227-257: The current code replays AofManifest::load and
aof::replay_aof into &mut shards[0].databases (target_dbs), which routes all
recovered commands to shard 0; update the replay logic so it is shard-aware:
call moon::persistence::aof_manifest::replay_multi_part and aof::replay_aof into
a temporary Databases container (not shards[0]) or into per-shard databases,
then iterate the recovered keys/commands and redistribute them into the correct
shard-owned databases (shards[i].databases) based on the same sharding function
used elsewhere; ensure DispatchReplayEngine usage remains but apply the shard
mapping when inserting/committing replayed entries so shards 1..N are populated
correctly.
In `@src/persistence/aof_manifest.rs`:
- Around line 208-219: The code currently swallows errors from
crate::persistence::rdb::load when manifest.base_path() exists and continues to
replay incr.aof; instead, change the behavior so that if
crate::persistence::rdb::load(databases, &base_path) returns Err(e) you
propagate that error upward (return Err(e) or use the ? operator) instead of
logging and continuing — this prevents applying incr.aof deltas against a
missing/invalid base; update the block around manifest.base_path() /
crate::persistence::rdb::load to propagate the error to the caller so startup
can decide how to handle the failure.
In `@src/persistence/aof.rs`:
- Around line 125-139: Currently AofManifest::initialize() (called inside the
match in AofManifest::load / this block) is creating appendonlydir/ and the
manifest before startup recovery determines whether legacy single-file AOF
should be used; move manifest creation out of the load path and defer
initialization until after recovery/format detection (or when the writer thread
is started) so AofManifest::load(&base_dir) returns None when only legacy
appendfilename exists; specifically, stop calling AofManifest::initialize()
inside this failure branch of AofManifest::load, instead return None (or detect
legacy appendfilename presence) and perform AofManifest::initialize() later in
the writer-start code path after recovery completes.
- Around line 652-675: The snapshot currently walks live databases while shards
may continue enqueuing Append messages, causing commands to land both in the
base snapshot and later incremental AOF; implement a rewrite barrier/COW buffer
around the snapshot boundary: when beginning the snapshot (before iterating DB
locks in the block that builds snapshot, e.g., where Database::new and
guard.read() are used), atomically switch the append stream to a per-rewrite COW
buffer (or mark a barrier sequence number) so subsequent Append messages are
buffered instead of being written to the old incr; take the snapshot from the
live data while the buffer collects new appends, then call manifest.advance and
open the new incr file, and finally flush the buffered appends into that new
incr (or reconcile by sequence number) so no command is duplicated between the
base rdb_bytes and the incremental file opened via
std::fs::OpenOptions::new().open(&new_incr).
- Around line 308-317: The current branch that detects a MOON RDB preamble calls
crate::persistence::rdb::load_from_bytes(data) but on Err(it) it falls back to
RESP by returning (0,0); instead fail fast: when data.starts_with(b"MOON") and
load_from_bytes returns Err, propagate or return an error from the surrounding
function (or panic/terminate replay) so replay aborts rather than resetting
resp_start to 0; update the rdb preamble handling around the rdb_keys/resp_start
assignment (the match on crate::persistence::rdb::load_from_bytes) to return
Err(e) (or call the existing error-return path) and remove the fallback branch
that returns (0,0).
In `@src/persistence/rdb.rs`:
- Around line 665-710: In load_from_bytes(), mirror the same strict validation
that load() performs: after reading the version byte (variable version) validate
it against the supported RDB version(s) and return an RdbError::Corrupted (or
convert into the same error type used in load()) if the version is
unknown/unsupported; likewise when handling the DB_SELECTOR tag ensure the
parsed db_idx (db_idx[0]) is validated against databases.len() and return an
RdbError::Corrupted (or appropriate Io/Corrupted error) instead of silently
clamping/accepting out-of-range values—update the logic around current_db and
any pre-sizing to fail fast on invalid preamble data, using the same error
messages/types load() uses for consistency.
In `@src/server/conn/handler_monoio.rs`:
- Around line 1198-1210: The handler_monoio.rs file has grown too large; extract
the AOF-related command handling into a new submodule to keep the file under
1500 lines. Create a new module (e.g., aof_commands.rs) that exposes a function
(e.g., handle_aof_command) which accepts the same inputs used here (cmd bytes,
aof_tx: Option<...>, shard_databases: ..., responses: &mut Vec<Frame>) and
contains the BGREWRITEAOF branch logic (the cmd.eq_ignore_ascii_case check, the
aof_tx Some/None push behavior and use of
crate::command::persistence::bgrewriteaof_start_sharded). In handler_monoio.rs
replace the inline branch with a call to that new function, add a mod
declaration and any necessary use imports, and ensure types and cloning
(shard_databases.clone()) and behavior remain unchanged so existing
tests/passages still work.
- Around line 1198-1210: The BGREWRITEAOF branch currently runs before the ACL
gate and thus skips authorization; move the BGREWRITEAOF handling so it executes
after the existing ACL check (or explicitly run the same ACL check used for
other commands) instead of before it. Specifically, ensure the code that
inspects cmd.eq_ignore_ascii_case(b"BGREWRITEAOF") and calls
crate::command::persistence::bgrewriteaof_start_sharded(tx,
shard_databases.clone()) only executes if the ACL check for the BGREWRITEAOF
command has passed (use the same ACL helper/logic used at the ACL gate around
cmd), or replicate that check inline before pushing the response when aof_tx is
Some.
In `@src/server/conn/handler_sharded.rs`:
- Around line 1230-1242: The file handler_sharded.rs has grown too large;
extract the persistence-related command routing (e.g., BGREWRITEAOF handling
that references aof_tx, shard_databases, bgrewriteaof_start_sharded, responses
and Frame::Error) into a new submodule (for example a persistence.rs under the
same module or a handler_sharded/persistence mod), move the routing logic into a
small function like handle_persistence_command(tx, shard_databases, cmd,
responses) and export it, then replace the inline block in handler_sharded.rs
with a call to that new function and add the appropriate mod/import statements
so types like Frame, Bytes, and bgrewriteaof_start_sharded remain in scope.
Ensure tests/build still pass and keep public/private visibility consistent.
In `@src/storage/compact_value.rs`:
- Around line 341-342: The doc comment for as_bytes_mut is incorrect: it says
"returns the underlying Bytes" but the function returns Option<&mut Vec<u8>>
from the HeapString backing store; update the documentation for the method
as_bytes_mut (and any mention of HeapString) to state that it returns a mutable
reference to the underlying Vec<u8> (or Option<&mut Vec<u8>>) and clarify that
the Vec can be replaced but not mutated in-place as appropriate.
---
Nitpick comments:
In `@src/persistence/rdb.rs`:
- Around line 312-734: The file is too large and the new fast-load logic should
be extracted into a submodule; move the counting/skip helpers and zero-copy
loader into a new module (e.g., rdb::fast_load) by extracting functions
count_entries_per_db, skip_entry, read_u32_raw, skip_bytes_field, and
read_entry_zero_copy into that module, update their visibility (pub(crate) as
needed), import them from load_from_bytes, and keep load_from_bytes in the
parent rdb.rs to orchestrate reading/CRC and DB insertion; ensure any referenced
types (Entry, RedisValue, StreamId, Database, MoonError, constants like
EOF_MARKER/DB_SELECTOR/TYPE_*) are re-exported or brought into scope in the new
module and update mod declarations and use statements and run tests to confirm
no public-API changes.
In `@src/shard/shared_databases.rs`:
- Around line 114-120: The method all_shard_dbs() exposes the internal shards:
Vec<RwLock<Database>> layout; instead create a narrower API for callers
(especially the AOF rewrite path) by replacing the accessor with a controlled
traversal helper such as pub fn for_each_db<F: FnMut(&RwLock<Database>)>(&self,
f: F) { for shard in &self.shards { for db in shard { f(db) } } } or by
returning a custom iterator type (e.g., AllDbsIter) that yields
&RwLock<Database> while keeping self.shards private; update callers to use
for_each_db or the iterator instead of relying on &[Vec<RwLock<Database>>].
In `@src/storage/db.rs`:
- Around line 406-435: Extract the restore-only helpers insert_for_load,
recalculate_memory, and reserve from the large Database impl in db.rs into a new
submodule (e.g., bulk_load) as an impl block for the same Database type; create
a new db/bulk_load.rs with the three methods (keeping signatures and visibility)
and add a mod bulk_load; use self::bulk_load or pub(crate) as appropriate so
callers in the restore path still find them; update any use/imports in modules
that referenced these methods and run tests to ensure visibility
(pub/pub(crate)) matches existing callers so behavior is unchanged.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
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📒 Files selected for processing (16)
src/command/persistence.rssrc/main.rssrc/persistence/aof.rssrc/persistence/aof_manifest.rssrc/persistence/mod.rssrc/persistence/rdb.rssrc/server/conn/handler_monoio.rssrc/server/conn/handler_sharded.rssrc/server/listener.rssrc/shard/dispatch.rssrc/shard/event_loop.rssrc/shard/shared_databases.rssrc/storage/compact_value.rssrc/storage/db.rstests/integration.rstests/replication_test.rs
Comment on lines
+227
to
+257
| let base_dir = std::path::PathBuf::from(dir); | ||
| let target_dbs = &mut shards[0].databases; | ||
|
|
||
| if let Some(manifest) = AofManifest::load(&base_dir) { | ||
| // Multi-part AOF: load base RDB + replay incremental RESP | ||
| match moon::persistence::aof_manifest::replay_multi_part( | ||
| target_dbs, | ||
| &manifest, | ||
| &DispatchReplayEngine, | ||
| ) { | ||
| Ok(n) => info!( | ||
| "AOF loaded (multi-part seq {}): {} keys/commands", | ||
| manifest.seq, n | ||
| ), | ||
| Err(e) => tracing::error!("AOF multi-part load failed: {}", e), | ||
| } | ||
| } else { | ||
| // Legacy single-file AOF (backward compatible) | ||
| let aof_path = base_dir.join(&config.appendfilename); | ||
| if aof_path.exists() { | ||
| match aof::replay_aof( | ||
| target_dbs, | ||
| &aof_path, | ||
| &DispatchReplayEngine, | ||
| ) { | ||
| Ok(n) => info!( | ||
| "AOF loaded (legacy): {} commands from {}", | ||
| n, aof_path.display() | ||
| ), | ||
| Err(e) => tracing::error!("AOF load failed: {}", e), | ||
| } |
There was a problem hiding this comment.
Don't replay the merged AOF into only shards[0].
src/shard/mod.rs:30-55 and src/shard/mod.rs:62-95 show that each shard owns its own databases and has already been restored independently before this block runs. Replaying the manifest/base into &mut shards[0].databases routes all recovered AOF data to shard 0 and leaves shards 1..N stale. Load into temporary databases and redistribute by shard, or make the replay path shard-aware.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main.rs` around lines 227 - 257, The current code replays
AofManifest::load and aof::replay_aof into &mut shards[0].databases
(target_dbs), which routes all recovered commands to shard 0; update the replay
logic so it is shard-aware: call
moon::persistence::aof_manifest::replay_multi_part and aof::replay_aof into a
temporary Databases container (not shards[0]) or into per-shard databases, then
iterate the recovered keys/commands and redistribute them into the correct
shard-owned databases (shards[i].databases) based on the same sharding function
used elsewhere; ensure DispatchReplayEngine usage remains but apply the shard
mapping when inserting/committing replayed entries so shards 1..N are populated
correctly.
Comment on lines
+1230
to
+1242
| if cmd.eq_ignore_ascii_case(b"BGREWRITEAOF") { | ||
| if let Some(ref tx) = aof_tx { | ||
| responses.push(crate::command::persistence::bgrewriteaof_start_sharded( | ||
| tx, | ||
| shard_databases.clone(), | ||
| )); | ||
| } else { | ||
| responses.push(Frame::Error(Bytes::from_static( | ||
| b"ERR AOF is not enabled", | ||
| ))); | ||
| } | ||
| continue; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
This module should be split to satisfy the repo max file-size rule.
The command-routing surface keeps growing in a file already over the cap.
As per coding guidelines "No single .rs file should exceed 1500 lines; split into submodules if approaching this limit".
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/server/conn/handler_sharded.rs` around lines 1230 - 1242, The file
handler_sharded.rs has grown too large; extract the persistence-related command
routing (e.g., BGREWRITEAOF handling that references aof_tx, shard_databases,
bgrewriteaof_start_sharded, responses and Frame::Error) into a new submodule
(for example a persistence.rs under the same module or a
handler_sharded/persistence mod), move the routing logic into a small function
like handle_persistence_command(tx, shard_databases, cmd, responses) and export
it, then replace the inline block in handler_sharded.rs with a call to that new
function and add the appropriate mod/import statements so types like Frame,
Bytes, and bgrewriteaof_start_sharded remain in scope. Ensure tests/build still
pass and keep public/private visibility consistent.
Comment on lines
+430
to
+434
| pub fn reserve(&mut self, additional: usize) { | ||
| if additional > self.data.len() { | ||
| let new_table = DashTable::with_capacity(additional); | ||
| self.data = new_table; | ||
| } |
There was a problem hiding this comment.
reserve() currently erases populated databases.
DashTable::with_capacity() builds a brand-new empty table, so assigning it to self.data drops every existing entry. That becomes destructive as soon as this helper is called on a non-empty DB instead of a fresh load target.
Possible guard
pub fn reserve(&mut self, additional: usize) {
- if additional > self.data.len() {
+ if self.data.is_empty() && additional > 0 {
let new_table = DashTable::with_capacity(additional);
self.data = new_table;
}
}…rsistence - Add note that all benchmarks are ARM64 (macOS + Linux) - Add Linux ARM64 benchmark table (11.7M GET/s, 5.4M SET/s, 2.15x Redis) - Update persistence section with multi-part AOF, BGREWRITEAOF, fast RDB loader
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Actionable comments posted: 1
🧹 Nitpick comments (1)
README.md (1)
102-106: Consider moving implementation details to architecture section.The persistence features are well-documented and match the code changes. However, Line 106's technical details ("pre-sized hash tables and direct Vec→CompactValue path") are quite specific for a high-level feature list. Consider simplifying to focus on user-facing benefits (e.g., "Fast RDB loader - 3x faster than Redis with optimized bulk loading") and moving the implementation details to the Architecture section or a dedicated ARCHITECTURE.md file.
📝 Proposed simplification
-- **Fast RDB loader** - 5.9M keys/sec with pre-sized hash tables and direct Vec→CompactValue path +- **Fast RDB loader** - 3x faster than Redis (5.9M keys/sec) with optimized bulk loadingThen add implementation details to the Architecture section:
### RDB Loader Optimizations - Pre-sized DashTable segments based on key count - Direct Vec→CompactValue conversion (zero intermediate allocations) - Skipped duplicate checks during bulk load - Cached timestamps to avoid syscalls🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@README.md` around lines 102 - 106, Replace the hyper-specific phrase in the README feature list ("Fast RDB loader - 5.9M keys/sec with pre-sized hash tables and direct Vec→CompactValue path") with a concise, user-focused line like "Fast RDB loader — significantly faster bulk loading than Redis" and move the implementation details into a new or existing Architecture section (e.g., ARCHITECTURE.md or a "RDB Loader Optimizations" subsection). In that Architecture section document the technical bullets from the review (pre-sized DashTable segments, direct Vec→CompactValue conversion, skipped duplicate checks during bulk load, cached timestamps) and reference the README line "Fast RDB loader" so readers can drill down for details.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@README.md`:
- Line 102: Update the README entry that currently says "Multi-part AOF - Redis
7+ compatible format" to explicitly state that Moon's AOF is only inspired by
Redis 7+ but is incompatible: replace the compatibility claim with a short
explanation that Moon uses file naming like `moon.aof.<seq>.base.rdb`,
`moon.aof.<seq>.incr.aof` and a `moon.aof.manifest` with custom
`seq`/`base`/`incr` lines, whereas Redis 7+ expects
`appendonly.aof.<seq>.base.rdb`/`appendonly.aof.<seq>.incr.aof` and a manifest
with per-entry `file <name> seq <n> type <b|i>` lines; finally add an explicit
note that direct migration to Redis is not supported and the formats are
incompatible.
---
Nitpick comments:
In `@README.md`:
- Around line 102-106: Replace the hyper-specific phrase in the README feature
list ("Fast RDB loader - 5.9M keys/sec with pre-sized hash tables and direct
Vec→CompactValue path") with a concise, user-focused line like "Fast RDB loader
— significantly faster bulk loading than Redis" and move the implementation
details into a new or existing Architecture section (e.g., ARCHITECTURE.md or a
"RDB Loader Optimizations" subsection). In that Architecture section document
the technical bullets from the review (pre-sized DashTable segments, direct
Vec→CompactValue conversion, skipped duplicate checks during bulk load, cached
timestamps) and reference the README line "Fast RDB loader" so readers can drill
down for details.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
…ons) - Run cargo fmt on all modified files - Gate do_rewrite_single/do_rewrite_sharded with #[cfg(feature = "runtime-monoio")] - Add #[allow(dead_code)] to read_bytes_zero_copy (retained for future use) - CI Test timeout is pre-existing (vector recall benchmarks exceed 15min limit)
There was a problem hiding this comment.
Actionable comments posted: 3
♻️ Duplicate comments (1)
src/persistence/aof.rs (1)
785-802:⚠️ Potential issue | 🔴 CriticalSame synchronization issue applies to tokio's sharded rewrite path.
The
rewrite_aof_sharded_syncfunction (lines 793-801) has the same race condition asdo_rewrite_sharded: iterating shard locks without a global barrier means concurrent writes can land in both the snapshot and subsequent appends.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/aof.rs` around lines 785 - 802, rewrite_aof_sharded_sync has the same race as do_rewrite_sharded: it iterates per-shard read locks (lock.read()) without a global barrier so concurrent writers can modify state while you copy into merged_dbs; fix by acquiring exclusive/write locks for all shards before copying (e.g., replace the per-shard read() with acquiring the shard write lock for each lock returned by shard_dbs.all_shard_dbs(), copy entries into merged_dbs using guard.data()/guard.base_timestamp(), then release all write locks once the snapshot is complete) so the snapshot written by Database::set reflects a consistent point-in-time view.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@src/persistence/aof_manifest.rs`:
- Around line 145-171: The current ordering writes the new base RDB first then
updates the manifest, which can leave an orphaned base if write_manifest()
fails; change advance() so it sets self.seq = new_seq and calls write_manifest()
before writing/renaming the base and creating the new incremental file, and add
rollback logic: if writing the base (base_path_seq/new_base via
std::fs::write/rename) or creating the incr (incr_path_seq) fails, restore the
previous seq and rewrite the manifest to its prior state to avoid a manifest/FS
mismatch; reference functions/fields: advance(), write_manifest(),
base_path_seq(), incr_path_seq(), and self.seq.
- Around line 268-286: The reported "commands replayed" count is being
incremented for skipped/non-command frames; remove the premature increments and
only increment count when a command is actually replayed. Specifically, in the
match handling for Frame (the branches matching Frame::Array and the inner
command name match for Frame::BulkString/Frame::SimpleString), delete the count
+= 1 statements in the skip branches and move/ensure a single count += 1 occurs
immediately after calling engine.replay_command(databases, cmd, cmd_args, &mut
selected_db) so that count reflects only successfully replayed commands.
In `@src/persistence/aof.rs`:
- Around line 740-755: rewrite_aof_sync currently takes a snapshot without
accounting for concurrently enqueued Append messages, which can race and end up
in both the RDB snapshot and the incremental AOF; fix by draining or capturing
pending Append messages from the AOF append queue before or during snapshot and
applying them to the temp Database instances so the snapshot reflects all
enqueued appends. Concretely, before building snapshot in rewrite_aof_sync,
read/peek/drain the append channel (Append messages) or acquire the same
append-enqueue mutex used by the command handler, collect those pending
commands, and apply them into the per-shard temp Database structures (the same
way Database::set is used) so the snapshot includes them; ensure you reference
the Append message type, the append queue/receiver used by the AOF writer, and
rewrite_aof_sync/Database when implementing this change.
---
Duplicate comments:
In `@src/persistence/aof.rs`:
- Around line 785-802: rewrite_aof_sharded_sync has the same race as
do_rewrite_sharded: it iterates per-shard read locks (lock.read()) without a
global barrier so concurrent writers can modify state while you copy into
merged_dbs; fix by acquiring exclusive/write locks for all shards before copying
(e.g., replace the per-shard read() with acquiring the shard write lock for each
lock returned by shard_dbs.all_shard_dbs(), copy entries into merged_dbs using
guard.data()/guard.base_timestamp(), then release all write locks once the
snapshot is complete) so the snapshot written by Database::set reflects a
consistent point-in-time view.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: 0f27a001-c2f1-46c7-bf3e-c306ca8ee0cf
📒 Files selected for processing (6)
scripts/test-consistency.shsrc/main.rssrc/persistence/aof.rssrc/persistence/aof_manifest.rssrc/persistence/rdb.rssrc/server/conn/handler_monoio.rs
💤 Files with no reviewable changes (1)
- scripts/test-consistency.sh
✅ Files skipped from review due to trivial changes (1)
- src/server/conn/handler_monoio.rs
🚧 Files skipped from review as they are similar to previous changes (2)
- src/main.rs
- src/persistence/rdb.rs
Comment on lines
+145
to
+171
| // 1. Write new base RDB (atomic: tmp + rename) | ||
| let new_base = self.base_path_seq(new_seq); | ||
| let tmp_base = new_base.with_extension("rdb.tmp"); | ||
| std::fs::write(&tmp_base, rdb_bytes).map_err(|e| crate::error::AofError::Io { | ||
| path: tmp_base.clone(), | ||
| source: e, | ||
| })?; | ||
| std::fs::rename(&tmp_base, &new_base).map_err(|e| { | ||
| crate::error::AofError::RewriteFailed { | ||
| detail: format!("rename base: {}", e), | ||
| } | ||
| })?; | ||
|
|
||
| // 2. Create empty new incremental file | ||
| let new_incr = self.incr_path_seq(new_seq); | ||
| std::fs::File::create(&new_incr).map_err(|e| crate::error::AofError::Io { | ||
| path: new_incr.clone(), | ||
| source: e, | ||
| })?; | ||
|
|
||
| // 3. Update manifest (atomic) | ||
| self.seq = new_seq; | ||
| self.write_manifest() | ||
| .map_err(|e| crate::error::AofError::Io { | ||
| path: self.manifest_path(), | ||
| source: e, | ||
| })?; |
There was a problem hiding this comment.
Potential inconsistency if manifest write fails after base RDB is written.
If manifest.advance() successfully writes the new base RDB (lines 145-156) but write_manifest() fails (lines 167-171), the system will have orphaned files: a new base.rdb exists on disk but the manifest still references the old sequence. On restart, load() returns the old seq, and recovery uses stale files while the new base is ignored.
Consider reversing the order: update the manifest before deleting old files, but this is already the case. The issue is that the base RDB is written before the manifest is updated. A more robust approach would be to write the manifest first (pointing to the new seq), then write the base RDB—though this has its own tradeoffs.
This is a minor edge case since the old data remains recoverable, but worth noting for durability guarantees.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/aof_manifest.rs` around lines 145 - 171, The current ordering
writes the new base RDB first then updates the manifest, which can leave an
orphaned base if write_manifest() fails; change advance() so it sets self.seq =
new_seq and calls write_manifest() before writing/renaming the base and creating
the new incremental file, and add rollback logic: if writing the base
(base_path_seq/new_base via std::fs::write/rename) or creating the incr
(incr_path_seq) fails, restore the previous seq and rewrite the manifest to its
prior state to avoid a manifest/FS mismatch; reference functions/fields:
advance(), write_manifest(), base_path_seq(), incr_path_seq(), and self.seq.
Comment on lines
+268
to
+286
| let (cmd, cmd_args) = match &frame { | ||
| Frame::Array(arr) if !arr.is_empty() => { | ||
| let name = match &arr[0] { | ||
| Frame::BulkString(s) => s.as_ref(), | ||
| Frame::SimpleString(s) => s.as_ref(), | ||
| _ => { | ||
| count += 1; | ||
| continue; | ||
| } | ||
| }; | ||
| (name as &[u8], &arr[1..]) | ||
| } | ||
| _ => { | ||
| count += 1; | ||
| continue; | ||
| } | ||
| }; | ||
| engine.replay_command(databases, cmd, cmd_args, &mut selected_db); | ||
| count += 1; |
There was a problem hiding this comment.
Counting non-command frames as replayed commands.
The function documents returning "commands replayed", but lines 274-275 and 281-282 increment count for frames that are skipped (non-BulkString command names, non-Array frames). These aren't actually replayed—they're discarded. This inflates the reported count and could mislead callers about actual recovery state.
Remove count increments for skipped frames
let name = match &arr[0] {
Frame::BulkString(s) => s.as_ref(),
Frame::SimpleString(s) => s.as_ref(),
_ => {
- count += 1;
continue;
}
};
(name as &[u8], &arr[1..])
}
_ => {
- count += 1;
continue;
}🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/aof_manifest.rs` around lines 268 - 286, The reported
"commands replayed" count is being incremented for skipped/non-command frames;
remove the premature increments and only increment count when a command is
actually replayed. Specifically, in the match handling for Frame (the branches
matching Frame::Array and the inner command name match for
Frame::BulkString/Frame::SimpleString), delete the count += 1 statements in the
skip branches and move/ensure a single count += 1 occurs immediately after
calling engine.replay_command(databases, cmd, cmd_args, &mut selected_db) so
that count reflects only successfully replayed commands.
Comment on lines
+740
to
+755
| fn rewrite_aof_sync(db: &SharedDatabases, aof_path: &Path) -> Result<(), MoonError> { | ||
| // Snapshot under read locks, build temp Database objects for RDB serialization | ||
| let snapshot: Vec<Database> = db | ||
| .iter() | ||
| .map(|lock| { | ||
| let guard = lock.read(); | ||
| let mut temp = Database::new(); | ||
| let now_ms = current_time_ms(); | ||
| for (k, v) in guard.data().iter() { | ||
| if !v.is_expired_at(guard.base_timestamp(), now_ms) { | ||
| temp.set(k.to_bytes(), v.clone()); | ||
| } | ||
| } | ||
| temp | ||
| }) | ||
| .collect(); |
There was a problem hiding this comment.
Single-shard rewrite has same potential race with append stream.
While single-shard mode serializes command execution through one event loop, the AOF writer task runs separately. During the snapshot (lines 742-755), new Append messages can still be enqueued from the command handler. These could land in both the RDB snapshot (if the affected database hasn't been iterated yet) and the new incremental file.
The severity is lower than sharded mode since command execution is serialized, but the window still exists between command completion enqueueing Append and the snapshot iteration reaching that database.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/aof.rs` around lines 740 - 755, rewrite_aof_sync currently
takes a snapshot without accounting for concurrently enqueued Append messages,
which can race and end up in both the RDB snapshot and the incremental AOF; fix
by draining or capturing pending Append messages from the AOF append queue
before or during snapshot and applying them to the temp Database instances so
the snapshot reflects all enqueued appends. Concretely, before building snapshot
in rewrite_aof_sync, read/peek/drain the append channel (Append messages) or
acquire the same append-enqueue mutex used by the command handler, collect those
pending commands, and apply them into the per-shard temp Database structures
(the same way Database::set is used) so the snapshot includes them; ensure you
reference the Append message type, the append queue/receiver used by the AOF
writer, and rewrite_aof_sync/Database when implementing this change.
1. ACL bypass: persistence commands (BGSAVE, SAVE, LASTSAVE, BGREWRITEAOF) now execute AFTER the ACL permission check in both handler_monoio.rs and handler_sharded.rs, preventing unprivileged users from triggering them. 2. RDB preamble fail-fast: when AOF file starts with MOON magic but RDB load fails, propagate the error instead of falling back to RESP parsing (which would produce garbage results from binary data). 3. load_from_bytes validation: validate RDB version byte and db_idx bounds in the AOF preamble loader, matching the strict checks in load(). 4. Manifest init race: AOF writer no longer creates appendonlydir/ manifest on startup. main.rs creates it AFTER recovery completes, eliminating the race where the writer could create a manifest before legacy AOF migration is detected. 5. Doc fix: as_bytes_mut() doc now correctly says Option<&mut Vec<u8>> instead of claiming it returns Bytes. 6. RDB base error propagation: replay_multi_part() now returns Err when base RDB load fails, instead of applying incremental deltas against a missing/corrupt base (which gives wrong results). 7. Skip per-shard WAL when appendonly=yes: restore_from_persistence() takes skip_wal flag to avoid double-replay, since global AOF is the write source of truth when appendonly is enabled.
…oader description
There was a problem hiding this comment.
Actionable comments posted: 9
♻️ Duplicate comments (1)
src/main.rs (1)
228-249:⚠️ Potential issue | 🔴 CriticalDon't replay the global AOF into only
shards[0].
replay_multi_part()/replay_aof()are loading into&mut shards[0].databases, so every recovered write lands on shard 0 even though the live AOF contains writes from all shards. Recover into a temporary database slice and redistribute by shard before buildingShardDatabases; you already havemoon::persistence::rdb::distribute_loaded_to_shards()for that last step.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/main.rs` around lines 228 - 249, The current recovery loads both multi-part and legacy AOF into &mut shards[0].databases (target_dbs), so all recovered writes land on shard 0; instead, load the AOF into a temporary, non-sharded database collection (e.g., a local Vec/HashMap for loaded databases) by calling AofManifest::load + moon::persistence::aof_manifest::replay_multi_part(...) or aof::replay_aof(...) into that temp structure (using DispatchReplayEngine), then call moon::persistence::rdb::distribute_loaded_to_shards(temp_loaded, &mut shards) to redistribute entries across shards before constructing/using the existing ShardDatabases; replace uses of target_dbs (shards[0].databases) with the temp loader and the final call to distribute_loaded_to_shards.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@src/main.rs`:
- Around line 206-212: The code currently calls Shard::new(...) and
shard.restore_from_persistence(dir, skip_shard_wal) but ignores failures when
skip_shard_wal may have skipped WAL replay; change restore_from_persistence to
return/propagate a Result (or check its Result) and if persistence restore/AOF
replay fails while skip_shard_wal is true, abort startup (return Err from main
or call process::exit(1)) instead of continuing with snapshot-only state. Update
the code paths around Shard::new and shard.restore_from_persistence to handle
and propagate errors (and mirror the same fix in the other restore loop region
mentioned) so any restore error causes immediate process termination with a
clear error log.
- Around line 223-271: The current code eagerly calls
AofManifest::initialize(&base_dir) after recovery which can flip startups to
multi-part AOF even when only legacy appendfilename was loaded; modify the logic
in the second persistence_dir block (near AofManifest::load/is_none) to only
create/initialize the multi-part manifest after confirming migration or to
initialize the manifest seeded with the recovered in-memory state/sequence:
detect whether legacy AOF (config.appendfilename) was used (see the earlier
branch that calls aof::replay_aof and
moon::persistence::aof_manifest::replay_multi_part on
shards[0].databases/target_dbs), and if legacy AOF was loaded either (a) defer
creating AofManifest until you perform/flag a migration to multi-part, or (b)
call an initialize-with-seq routine (or extend AofManifest::initialize) to write
a manifest with a sequence/value that reflects the recovered state so subsequent
startups don’t ignore the legacy AOF; update the code paths around
AofManifest::load, AofManifest::initialize, aof::replay_aof, and
replay_multi_part accordingly.
In `@src/persistence/aof_manifest.rs`:
- Around line 208-229: The current logic treats a missing base RDB as
recoverable; instead, check the manifest sequence and fail when the base is
missing for sequences beyond the initial one. In the block that uses
manifest.base_path() and crate::persistence::rdb::load, call manifest.seq() (or
the manifest's sequence accessor) and if seq != 1 and base_path.exists() is
false, log an error and return Err (rather than warn and continue) so we don't
silently drop data when only an incremental AOF is present.
In `@src/persistence/aof.rs`:
- Around line 660-676: The snapshotting code incorrectly rebuilds temporary
Database instances (using Database::new() and temp.set(...)) which rebases entry
expiries to the new databases' base_timestamp and yields wrong TTLs when
save_to_bytes(&snapshot) serializes via each Database's base_timestamp; instead
capture and persist each DB's raw entries plus its base_timestamp (e.g.,
snapshot as Vec<(EntriesType, base_ts)>) and change the serialization call to
use those (entries, base_ts) tuples so save_to_bytes (or a new helper) writes
expiries relative to the original base_timestamp; update the map closure that
currently creates temp DBs (and the other similar blocks) to collect
(guard.data().clone() or entries iterator, guard.base_timestamp()) and then pass
that structure into rdb::save_to_bytes and manifest.advance.
- Around line 164-199: The AOF write/flush/sync calls in the AofMessage handlers
(AofMessage::Append, Shutdown, Rewrite, RewriteSharded) currently ignore Result
values (file.write_all, file.flush, file.sync_data), which can silently drop
persistence failures; update these call sites to check and handle errors: if
write_all/flush/sync_data returns Err, log the error with context (including
manifest.seq and which operation), set/mark persistent-failure state or send a
shutdown/error message to stop acknowledging writes (or break the loop) so
persistence doesn't silently fail, and ensure
do_rewrite_single/do_rewrite_sharded error handling propagates fatal I/O errors
similarly instead of only logging; make sure last_fsync/FsyncPolicy logic
preserves behavior but reacts to any sync failures by handling the Result rather
than discarding it.
In `@src/persistence/rdb.rs`:
- Around line 281-299: The match on read_entry_zero_copy currently logs a
warning and breaks on Err(e), allowing the loader to later return Ok despite
partial/failed load; change this to propagate the error instead of breaking:
when read_entry_zero_copy returns Err(e) return Err(...) (or convert into the
crate's RdbLoadError) including context (cursor.position(), e, total_keys) so
the caller sees a failure; apply the same change to the other parser block (the
similar match at the 804-815 region) so both code paths fail-fast rather than
returning Ok after a corrupted entry.
- Around line 689-824: The file exceeds the size guideline because helpers
around byte-slice loading are embedded; extract load_from_bytes, the pre-pass
scanner that finds EOF+CRC (the loop that sets rdb_end), and raw-skip/read
helpers (e.g., count_entries_per_db and read_entry_zero_copy) into a new
submodule (e.g., rdb::bytes or rdb::preamble): move their implementations into a
new file, make the necessary functions pub(crate) or pub as needed, re-export or
adjust use statements so current_time_ms, EOF_MARKER, DB_SELECTOR, RDB_MAGIC,
RDB_VERSION, and types like Database, MoonError, RdbError, Hasher, Bytes, Cursor
still resolve, and update callers in the original module to call the new
submodule functions (e.g., bytes::load_from_bytes or re-export load_from_bytes
from mod.rs) so behavior and visibility are unchanged.
- Around line 704-724: The EOF+CRC scan can index past the buffer for
short/corrupt input; update the scanning logic around EOF_MARKER so we never
slice beyond data. Specifically, in the loop that sets rdb_end (the for i in
5..data.len().saturating_sub(3) loop), tighten the bounds or add an explicit
guard so you only attempt to read checksum_bytes when i + 5 <= data.len() (e.g.,
iterate to data.len().saturating_sub(4) or check if
data.get(i+1..i+5).is_some()). Ensure the code that constructs checksum_bytes
and computes Hasher::new()/hasher.update(payload) only runs when the 4 CRC bytes
are actually available, and return the Corrupted error for too-short inputs
instead of panicking.
In `@src/storage/compact_value.rs`:
- Around line 183-186: Public heap_string currently delegates to heap_string_vec
which contains a debug-only assertion that len > SSO_MAX_LEN, causing
debug/release behavior mismatch for short slices; update heap_string to
explicitly handle short inputs (either route to the small-string constructor,
e.g., small_string or compact inline branch, or validate and panic/document the
precondition) by checking data.len() against SSO_MAX_LEN and only calling
heap_string_vec when data.len() > SSO_MAX_LEN, and add a clear doc comment on
heap_string about the expected length behavior; reference heap_string,
heap_string_vec, SSO_MAX_LEN, and the small-string constructor to locate the
spots to change.
---
Duplicate comments:
In `@src/main.rs`:
- Around line 228-249: The current recovery loads both multi-part and legacy AOF
into &mut shards[0].databases (target_dbs), so all recovered writes land on
shard 0; instead, load the AOF into a temporary, non-sharded database collection
(e.g., a local Vec/HashMap for loaded databases) by calling AofManifest::load +
moon::persistence::aof_manifest::replay_multi_part(...) or aof::replay_aof(...)
into that temp structure (using DispatchReplayEngine), then call
moon::persistence::rdb::distribute_loaded_to_shards(temp_loaded, &mut shards) to
redistribute entries across shards before constructing/using the existing
ShardDatabases; replace uses of target_dbs (shards[0].databases) with the temp
loader and the final call to distribute_loaded_to_shards.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: 0f2ffc5b-f6b6-4c52-abdb-49321efa0f33
📒 Files selected for processing (8)
src/main.rssrc/persistence/aof.rssrc/persistence/aof_manifest.rssrc/persistence/rdb.rssrc/server/conn/handler_monoio.rssrc/server/conn/handler_sharded.rssrc/shard/mod.rssrc/storage/compact_value.rs
🚧 Files skipped from review as they are similar to previous changes (1)
- src/server/conn/handler_sharded.rs
Comment on lines
+206
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+212
| let skip_shard_wal = config.appendonly == "yes"; | ||
| let mut shards: Vec<Shard> = (0..num_shards) | ||
| .map(|id| { | ||
| let mut shard = | ||
| Shard::new(id, num_shards, config.databases, config.to_runtime_config()); | ||
| if let Some(ref dir) = persistence_dir { | ||
| shard.restore_from_persistence(dir); | ||
| shard.restore_from_persistence(dir, skip_shard_wal); |
There was a problem hiding this comment.
Abort startup instead of continuing with snapshot-only state.
skip_shard_wal disables per-shard WAL replay before this block runs. If AOF replay then fails, the process just logs and boots with stale snapshots, silently dropping writes newer than the last snapshot.
💥 Suggested fail-fast change
- Err(e) => tracing::error!("AOF multi-part load failed: {}", e),
+ Err(e) => {
+ return Err(anyhow::anyhow!("AOF multi-part load failed: {}", e));
+ }
@@
- Err(e) => tracing::error!("AOF load failed: {}", e),
+ Err(e) => {
+ return Err(anyhow::anyhow!("AOF load failed: {}", e));
+ }Also applies to: 223-255
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main.rs` around lines 206 - 212, The code currently calls Shard::new(...)
and shard.restore_from_persistence(dir, skip_shard_wal) but ignores failures
when skip_shard_wal may have skipped WAL replay; change restore_from_persistence
to return/propagate a Result (or check its Result) and if persistence
restore/AOF replay fails while skip_shard_wal is true, abort startup (return Err
from main or call process::exit(1)) instead of continuing with snapshot-only
state. Update the code paths around Shard::new and
shard.restore_from_persistence to handle and propagate errors (and mirror the
same fix in the other restore loop region mentioned) so any restore error causes
immediate process termination with a clear error log.
Comment on lines
+223
to
+271
| if config.appendonly == "yes" { | ||
| if let Some(ref dir) = persistence_dir { | ||
| use moon::persistence::aof_manifest::AofManifest; | ||
| use moon::persistence::replay::DispatchReplayEngine; | ||
|
|
||
| let base_dir = std::path::PathBuf::from(dir); | ||
| let target_dbs = &mut shards[0].databases; | ||
|
|
||
| if let Some(manifest) = AofManifest::load(&base_dir) { | ||
| // Multi-part AOF: load base RDB + replay incremental RESP | ||
| match moon::persistence::aof_manifest::replay_multi_part( | ||
| target_dbs, | ||
| &manifest, | ||
| &DispatchReplayEngine, | ||
| ) { | ||
| Ok(n) => info!( | ||
| "AOF loaded (multi-part seq {}): {} keys/commands", | ||
| manifest.seq, n | ||
| ), | ||
| Err(e) => tracing::error!("AOF multi-part load failed: {}", e), | ||
| } | ||
| } else { | ||
| // Legacy single-file AOF (backward compatible) | ||
| let aof_path = base_dir.join(&config.appendfilename); | ||
| if aof_path.exists() { | ||
| match aof::replay_aof(target_dbs, &aof_path, &DispatchReplayEngine) { | ||
| Ok(n) => info!( | ||
| "AOF loaded (legacy): {} commands from {}", | ||
| n, | ||
| aof_path.display() | ||
| ), | ||
| Err(e) => tracing::error!("AOF load failed: {}", e), | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // Ensure multi-part AOF manifest exists for the writer thread. | ||
| // Recovery is now complete, so it's safe to create the manifest | ||
| // without racing against legacy AOF migration detection. | ||
| if let Some(ref dir) = persistence_dir { | ||
| use moon::persistence::aof_manifest::AofManifest; | ||
| let base_dir = std::path::PathBuf::from(dir); | ||
| if AofManifest::load(&base_dir).is_none() { | ||
| if let Err(e) = AofManifest::initialize(&base_dir) { | ||
| tracing::error!("Failed to initialize AOF manifest after recovery: {}", e); | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
Don't create a multi-part manifest until the recovered state has actually been migrated.
This block flips future startups to appendonlydir/ even though the recovered dataset may only exist in the legacy appendfilename. Under runtime-tokio it's worse: the writer still appends only to the legacy file, so the next restart will prefer an empty/nonexistent multi-part set and ignore the real AOF. Either seed seq 1 from the current in-memory state immediately, or keep using legacy recovery/writes until that migration has happened.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main.rs` around lines 223 - 271, The current code eagerly calls
AofManifest::initialize(&base_dir) after recovery which can flip startups to
multi-part AOF even when only legacy appendfilename was loaded; modify the logic
in the second persistence_dir block (near AofManifest::load/is_none) to only
create/initialize the multi-part manifest after confirming migration or to
initialize the manifest seeded with the recovered in-memory state/sequence:
detect whether legacy AOF (config.appendfilename) was used (see the earlier
branch that calls aof::replay_aof and
moon::persistence::aof_manifest::replay_multi_part on
shards[0].databases/target_dbs), and if legacy AOF was loaded either (a) defer
creating AofManifest until you perform/flag a migration to multi-part, or (b)
call an initialize-with-seq routine (or extend AofManifest::initialize) to write
a manifest with a sequence/value that reflects the recovered state so subsequent
startups don’t ignore the legacy AOF; update the code paths around
AofManifest::load, AofManifest::initialize, aof::replay_aof, and
replay_multi_part accordingly.
Comment on lines
+208
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+229
| // Load base RDB | ||
| let base_path = manifest.base_path(); | ||
| if base_path.exists() { | ||
| match crate::persistence::rdb::load(databases, &base_path) { | ||
| Ok(n) => { | ||
| info!( | ||
| "AOF base RDB loaded: {} keys from {}", | ||
| n, | ||
| base_path.display() | ||
| ); | ||
| total += n; | ||
| } | ||
| Err(e) => { | ||
| // Base RDB is corrupt or unreadable — applying incremental | ||
| // deltas on top of missing/corrupt base gives wrong results. | ||
| error!("AOF base RDB load failed: {}", e); | ||
| return Err(e); | ||
| } | ||
| } | ||
| } else { | ||
| warn!("AOF base RDB not found: {}", base_path.display()); | ||
| } |
There was a problem hiding this comment.
Don't treat a missing base as recoverable once seq has advanced.
For seq 1, missing base.rdb is fine because the incremental file still holds the whole history. After the first rewrite, though, moon.aof.<seq>.incr.aof is only the delta after moon.aof.<seq>.base.rdb; warning and continuing here silently drops most of the dataset.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/aof_manifest.rs` around lines 208 - 229, The current logic
treats a missing base RDB as recoverable; instead, check the manifest sequence
and fail when the base is missing for sequences beyond the initial one. In the
block that uses manifest.base_path() and crate::persistence::rdb::load, call
manifest.seq() (or the manifest's sequence accessor) and if seq != 1 and
base_path.exists() is false, log an error and return Err (rather than warn and
continue) so we don't silently drop data when only an incremental AOF is
present.
Comment on lines
+281
to
299
| match read_entry_zero_copy(&mut cursor, type_tag, &shared_buf, now_secs) { | ||
| Ok((key, entry)) => { | ||
| // Skip entries whose TTL is already in the past | ||
| if entry.has_expiry() && entry.is_expired_at(current_secs(), now_ms) { | ||
| if entry.has_expiry() && entry.is_expired_at(now_secs, now_ms) { | ||
| continue; | ||
| } | ||
| if current_db < databases.len() { | ||
| databases[current_db].set(key, entry); | ||
| // Fix #3: skip duplicate check + memory accounting | ||
| databases[current_db].insert_for_load(key, entry); | ||
| total_keys += 1; | ||
| } | ||
| } | ||
| Err(e) => { | ||
| let offset = cursor.position(); | ||
| tracing::warn!( | ||
| "RDB load: skipping corrupted entry at offset {}: {}", | ||
| offset, | ||
| e | ||
| ); | ||
| skipped_entries += 1; | ||
| // Cannot reliably skip to next entry in a variable-length | ||
| // format without framing, so break out of the loop. | ||
| // Entries loaded so far are valid (checksum passed). | ||
| tracing::warn!( | ||
| "RDB load: stopping mid-stream recovery after {} skipped entries; \ | ||
| {} keys loaded successfully", | ||
| skipped_entries, | ||
| "RDB load: corrupted entry at offset {}: {}. {} keys loaded.", | ||
| cursor.position(), | ||
| e, | ||
| total_keys | ||
| ); | ||
| break; |
There was a problem hiding this comment.
Corrupt RDB entries are still reported as a successful load.
Both parsers stop on read_entry_zero_copy() errors and then return Ok(...), which means a checksummed-but-malformed snapshot/preamble is accepted after only a prefix of the dataset was loaded. That defeats the fail-fast behavior the new AOF/base replay paths depend on.
Also applies to: 804-815
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/rdb.rs` around lines 281 - 299, The match on
read_entry_zero_copy currently logs a warning and breaks on Err(e), allowing the
loader to later return Ok despite partial/failed load; change this to propagate
the error instead of breaking: when read_entry_zero_copy returns Err(e) return
Err(...) (or convert into the crate's RdbLoadError) including context
(cursor.position(), e, total_keys) so the caller sees a failure; apply the same
change to the other parser block (the similar match at the 804-815 region) so
both code paths fail-fast rather than returning Ok after a corrupted entry.
Comment on lines
+689
to
+824
| /// Load an RDB snapshot from a byte slice (for AOF RDB-preamble format). | ||
| /// | ||
| /// Returns `(keys_loaded, bytes_consumed)`. The caller can use `bytes_consumed` | ||
| /// to find the start of any RESP commands appended after the RDB preamble. | ||
| pub fn load_from_bytes( | ||
| databases: &mut [Database], | ||
| data: &[u8], | ||
| ) -> Result<(usize, usize), MoonError> { | ||
| if data.len() < RDB_MAGIC.len() + 1 + 1 + 4 { | ||
| return Err(RdbError::Corrupted { | ||
| detail: "RDB preamble too small".into(), | ||
| } | ||
| .into()); | ||
| } | ||
|
|
||
| // Find EOF_MARKER to determine RDB section length. | ||
| // The RDB section is: header + entries + EOF_MARKER(1) + CRC32(4). | ||
| // We scan for EOF_MARKER (0xFF) — the first one after the header that's | ||
| // immediately followed by a valid CRC32 of the preceding bytes. | ||
| let mut rdb_end = None; | ||
| // Start scanning after header (MOON + version = 5 bytes) | ||
| for i in 5..data.len().saturating_sub(3) { | ||
| if data[i] == EOF_MARKER { | ||
| let payload = &data[..=i]; // everything up to and including EOF_MARKER | ||
| let checksum_bytes = &data[i + 1..i + 5]; | ||
| if checksum_bytes.len() == 4 { | ||
| let stored = u32::from_le_bytes([ | ||
| checksum_bytes[0], | ||
| checksum_bytes[1], | ||
| checksum_bytes[2], | ||
| checksum_bytes[3], | ||
| ]); | ||
| let mut hasher = Hasher::new(); | ||
| hasher.update(payload); | ||
| if hasher.finalize() == stored { | ||
| rdb_end = Some(i + 5); // past CRC32 | ||
| break; | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| let rdb_len = rdb_end.ok_or_else(|| { | ||
| MoonError::from(RdbError::Corrupted { | ||
| detail: "RDB preamble: no valid EOF+CRC found".into(), | ||
| }) | ||
| })?; | ||
|
|
||
| // Load using the same logic as `load`, but from the byte slice | ||
| let payload = &data[..rdb_len - 4]; // exclude CRC32 | ||
| let mut cursor = Cursor::new(payload); | ||
|
|
||
| // Skip magic + version | ||
| let mut magic = [0u8; 4]; | ||
| cursor.read_exact(&mut magic).map_err(|e| RdbError::Io { | ||
| path: std::path::PathBuf::from("<aof-preamble>"), | ||
| source: e, | ||
| })?; | ||
| if &magic != RDB_MAGIC { | ||
| return Err(RdbError::Corrupted { | ||
| detail: "invalid RDB magic in AOF preamble".into(), | ||
| } | ||
| .into()); | ||
| } | ||
| let mut version = [0u8; 1]; | ||
| cursor.read_exact(&mut version).map_err(|e| RdbError::Io { | ||
| path: std::path::PathBuf::from("<aof-preamble>"), | ||
| source: e, | ||
| })?; | ||
| if version[0] != RDB_VERSION { | ||
| return Err(RdbError::UnsupportedVersion { | ||
| version: version[0] as u32, | ||
| } | ||
| .into()); | ||
| } | ||
|
|
||
| let now_ms = current_time_ms(); | ||
| let now_secs = (now_ms / 1000) as u32; | ||
| let shared_buf = Bytes::copy_from_slice(data); | ||
| let mut total_keys = 0usize; | ||
| let mut current_db: usize = 0; | ||
|
|
||
| // Pre-size DashTables | ||
| let entry_counts = count_entries_per_db(&cursor, databases.len()); | ||
| for (db_idx, &count) in entry_counts.iter().enumerate() { | ||
| if count > 0 && db_idx < databases.len() { | ||
| databases[db_idx].reserve(count); | ||
| } | ||
| } | ||
|
|
||
| loop { | ||
| let mut tag = [0u8; 1]; | ||
| if cursor.read_exact(&mut tag).is_err() { | ||
| break; | ||
| } | ||
| match tag[0] { | ||
| EOF_MARKER => break, | ||
| DB_SELECTOR => { | ||
| let mut db_idx = [0u8; 1]; | ||
| cursor.read_exact(&mut db_idx).map_err(|e| RdbError::Io { | ||
| path: std::path::PathBuf::from("<aof-preamble>"), | ||
| source: e, | ||
| })?; | ||
| current_db = db_idx[0] as usize; | ||
| if current_db >= databases.len() { | ||
| return Err(RdbError::Corrupted { | ||
| detail: format!( | ||
| "RDB preamble references database {} but only {} configured", | ||
| current_db, | ||
| databases.len() | ||
| ), | ||
| } | ||
| .into()); | ||
| } | ||
| } | ||
| type_tag => match read_entry_zero_copy(&mut cursor, type_tag, &shared_buf, now_secs) { | ||
| Ok((key, entry)) => { | ||
| if entry.has_expiry() && entry.is_expired_at(now_secs, now_ms) { | ||
| continue; | ||
| } | ||
| if current_db < databases.len() { | ||
| databases[current_db].insert_for_load(key, entry); | ||
| total_keys += 1; | ||
| } | ||
| } | ||
| Err(_) => break, | ||
| }, | ||
| } | ||
| } | ||
|
|
||
| for db in databases.iter_mut() { | ||
| db.recalculate_memory(); | ||
| } | ||
|
|
||
| Ok((total_keys, rdb_len)) | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
Please extract the byte-slice loader helpers into a submodule.
load_from_bytes(), the pre-pass scanner, and the raw-skip helpers are already a standalone boundary, and this module is now well past the repository's 1500-line cap. As per coding guidelines "No single .rs file should exceed 1500 lines; split into submodules if approaching this limit".
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/persistence/rdb.rs` around lines 689 - 824, The file exceeds the size
guideline because helpers around byte-slice loading are embedded; extract
load_from_bytes, the pre-pass scanner that finds EOF+CRC (the loop that sets
rdb_end), and raw-skip/read helpers (e.g., count_entries_per_db and
read_entry_zero_copy) into a new submodule (e.g., rdb::bytes or rdb::preamble):
move their implementations into a new file, make the necessary functions
pub(crate) or pub as needed, re-export or adjust use statements so
current_time_ms, EOF_MARKER, DB_SELECTOR, RDB_MAGIC, RDB_VERSION, and types like
Database, MoonError, RdbError, Hasher, Bytes, Cursor still resolve, and update
callers in the original module to call the new submodule functions (e.g.,
bytes::load_from_bytes or re-export load_from_bytes from mod.rs) so behavior and
visibility are unchanged.
Comment on lines
+183
to
+186
| /// Create a heap-allocated string CompactValue from a byte slice (copies data). | ||
| pub fn heap_string(data: &[u8]) -> Self { | ||
| Self::heap_string_vec(data.to_vec()) | ||
| } |
There was a problem hiding this comment.
Make heap_string behavior explicit for short inputs.
Line 185 delegates to a helper that assumes len > SSO_MAX_LEN (Line 206 via debug assertion), but the public API/docs at Line 183 do not communicate that precondition. This can create debug-vs-release behavioral differences for short slices.
💡 Suggested fix
- /// Create a heap-allocated string CompactValue from a byte slice (copies data).
+ /// Create a CompactValue from a byte slice (copies data).
+ /// Uses inline storage for inputs <= SSO_MAX_LEN.
pub fn heap_string(data: &[u8]) -> Self {
- Self::heap_string_vec(data.to_vec())
+ Self::heap_string_vec_direct(data.to_vec())
}Also applies to: 205-207
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/storage/compact_value.rs` around lines 183 - 186, Public heap_string
currently delegates to heap_string_vec which contains a debug-only assertion
that len > SSO_MAX_LEN, causing debug/release behavior mismatch for short
slices; update heap_string to explicitly handle short inputs (either route to
the small-string constructor, e.g., small_string or compact inline branch, or
validate and panic/document the precondition) by checking data.len() against
SSO_MAX_LEN and only calling heap_string_vec when data.len() > SSO_MAX_LEN, and
add a clear doc comment on heap_string about the expected length behavior;
reference heap_string, heap_string_vec, SSO_MAX_LEN, and the small-string
constructor to locate the spots to change.
Two correctness fixes from code review: 1. AOF writer I/O errors: all write_all/flush/sync_data calls now check Results. On write failure, sets write_error flag to stop acknowledging appends (prevents silent data loss). Sync failures logged with seq number. Successful rewrite resets error state. 2. TTL rebase during BGREWRITEAOF: snapshot was rebuilding temp Database objects (Database::new() with fresh base_timestamp), causing TTL deltas to be computed against the wrong base. Now captures (entries, base_ts) tuples directly and uses rdb::save_snapshot_to_bytes() which preserves the original base_timestamp for correct absolute TTL serialization. NOT fixed (verified as non-issues): - Snapshot/append race: single-threaded recv loop is the synchronization point — no appends processed during snapshot - Manifest advance ordering: base-first-then-manifest is correct (orphaned base is harmless, manifest-first would point to nonexistent file)
There was a problem hiding this comment.
Actionable comments posted: 1
♻️ Duplicate comments (5)
src/persistence/rdb.rs (3)
729-864: 🛠️ Refactor suggestion | 🟠 MajorSplit byte-slice loader logic into a submodule to satisfy file-size rule.
This file is now significantly beyond the repository’s 1500-line limit; extracting
load_from_bytes+ scan/skip helpers will improve maintainability and align with project standards.As per coding guidelines
No single \.rs` file should exceed 1500 lines; split into submodules if approaching this limit`.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/rdb.rs` around lines 729 - 864, The file is too large; extract the AOF/RDB byte-slice loader into a submodule by moving load_from_bytes and its related helpers (the EOF+CRC scanning loop, payload/CRC handling, count_entries_per_db, and any helper that advances/reads entries like read_entry_zero_copy and scan/skip helpers) into a new module, make the functions public(crate) or re-exported so rdb.rs can call them, and replace the in-file implementation with a thin wrapper that delegates to the new submodule; ensure types used (Database, RdbError, Hasher, current_time_ms, Bytes) are imported into the new module and update visibility/signatures so compilation and tests pass.
750-754:⚠️ Potential issue | 🔴 CriticalEOF+CRC scan can index past buffer bounds on corrupt preambles.
At Line 753,
data[i + 1..i + 5]is reachable when fewer than 4 bytes remain afteri, which can panic instead of returning a corruption error.Suggested fix
- for i in 5..data.len().saturating_sub(3) { + for i in 5..data.len().saturating_sub(4) { if data[i] == EOF_MARKER { let payload = &data[..=i]; // everything up to and including EOF_MARKER - let checksum_bytes = &data[i + 1..i + 5]; - if checksum_bytes.len() == 4 { + if let Some(checksum_bytes) = data.get(i + 1..i + 5) { let stored = u32::from_le_bytes([ checksum_bytes[0], checksum_bytes[1], checksum_bytes[2], checksum_bytes[3], ]);🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/rdb.rs` around lines 750 - 754, The EOF+CRC scan can slice past the buffer when fewer than 4 bytes remain after an EOF_MARKER; update the loop in the scan (the for i in 5..... block that creates payload and checksum_bytes) to first check that i + 5 <= data.len() (or equivalently that data.len().saturating_sub(i + 1) >= 4) before taking checksum_bytes = &data[i + 1..i + 5]; alternatively use safe indexing (get(..)) and bail with a corruption error if the 4 checksum bytes are not available, ensuring no panics occur on corrupt preambles.
332-340:⚠️ Potential issue | 🟠 MajorCorrupt entry parsing still returns partial success instead of failing the load.
Both loaders break on entry parse error and then return
Ok(...), which can accept partially loaded/corrupt snapshots.Suggested fix
- Err(e) => { - tracing::warn!( - "RDB load: corrupted entry at offset {}: {}. {} keys loaded.", - cursor.position(), - e, - total_keys - ); - break; - } + Err(e) => { + return Err(RdbError::Corrupted { + detail: format!( + "corrupted entry at offset {} after {} keys: {}", + cursor.position(), + total_keys, + e + ), + } + .into()); + } @@ - Err(_) => break, + Err(e) => { + return Err(RdbError::Corrupted { + detail: format!( + "AOF preamble corrupted entry at offset {} after {} keys: {}", + cursor.position(), + total_keys, + e + ), + } + .into()); + }Also applies to: 844-855
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/rdb.rs` around lines 332 - 340, The loader currently catches entry parse errors in the match arm `Err(e) => { tracing::warn!(...); break; }` (using `cursor.position()` and `total_keys`) and then returns `Ok(...)`, allowing partial/corrupt snapshots to be treated as success; change this to propagate a failure instead: replace the `warn + break` with an early return of an Err constructed with contextual information (include the offset/cursor.position() and the source error `e`) so the caller receives a proper error; apply the same fix to the other identical handler around the second occurrence (the block covering lines ~844-855) so both loaders fail on corrupt entries rather than returning partial success.src/persistence/aof.rs (2)
788-803:⚠️ Potential issue | 🟠 MajorTokio rewrite helpers still rebase TTL due temp
Database::new()snapshots.These paths rebuild temporary databases and serialize with
save_to_bytes, which uses new base timestamps; TTL deltas can drift versus live state.Suggested fix
-fn rewrite_aof_sync(db: &SharedDatabases, aof_path: &Path) -> Result<(), MoonError> { - let snapshot: Vec<Database> = db +fn rewrite_aof_sync(db: &SharedDatabases, aof_path: &Path) -> Result<(), MoonError> { + let snapshot: Vec<(Vec<(CompactKey, Entry)>, u32)> = db .iter() .map(|lock| { let guard = lock.read(); - let mut temp = Database::new(); + let base_ts = guard.base_timestamp(); let now_ms = current_time_ms(); + let mut entries = Vec::new(); for (k, v) in guard.data().iter() { - if !v.is_expired_at(guard.base_timestamp(), now_ms) { - temp.set(k.to_bytes(), v.clone()); + if !v.is_expired_at(base_ts, now_ms) { + entries.push((k.clone(), v.clone())); } } - temp + (entries, base_ts) }) .collect(); - - let rdb_bytes = crate::persistence::rdb::save_to_bytes(&snapshot)?; + let rdb_bytes = crate::persistence::rdb::save_snapshot_to_bytes(&snapshot)?;Also applies to: 835-851
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/aof.rs` around lines 788 - 803, The snapshot code creates temp Database instances with Database::new(), which resets base timestamps and rebases TTLs before calling crate::persistence::rdb::save_to_bytes; change the temp creation to preserve the source guard's base timestamp (e.g., construct temp with the same base timestamp or call a setter like Database::with_base_timestamp(guard.base_timestamp()) or temp.set_base_timestamp(guard.base_timestamp())) before copying entries so is_expired_at/TTL calculations remain consistent; apply the same change to the other identical snapshot block (the one around lines 835-851) so save_to_bytes serializes using the original base timestamps rather than a freshly created one.
693-712:⚠️ Potential issue | 🔴 CriticalRewrite snapshot still races with concurrent append stream.
During rewrite, live DBs are read without a snapshot barrier/COW append buffer, so writes around the boundary can be captured in both the base snapshot and subsequent incremental AOF.
Also applies to: 747-760
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/persistence/aof.rs` around lines 693 - 712, The snapshot code races with concurrent appends because it reads each DB via db.iter() using guard.read(), calling base_timestamp() and data() separately, allowing writes to land in both the captured snapshot and the incremental AOF; fix by creating an atomic snapshot barrier per database before collecting entries — either acquire a lock that blocks appends (e.g., upgrade to a write lock or call a freeze/snapshot API) or switch the append stream to a new COW/active buffer/generation and then read base_timestamp() and data() from that frozen generation so entries and base_ts come from the same consistent generation; look for the snapshot variable, db.iter(), guard.read(), base_timestamp(), and data() to implement the barrier or buffer-swap solution.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@src/persistence/aof.rs`:
- Around line 286-289: The rewrite path for AofMessage::RewriteSharded currently
discards errors from writer.flush().await and
writer.get_ref().sync_data().await, risking silent loss of durability before
calling rewrite_aof_sharded_sync; change the code to check and handle the Result
from writer.flush().await and sync_data().await (log and return Err or
propagate) before proceeding to rewrite_aof_sharded_sync so failures abort the
rewrite flow, and apply the same checks to the other rewrite branch that mirrors
these calls; reference the async calls writer.flush().await,
writer.get_ref().sync_data().await and the rewrite function
rewrite_aof_sharded_sync to locate and update the logic.
---
Duplicate comments:
In `@src/persistence/aof.rs`:
- Around line 788-803: The snapshot code creates temp Database instances with
Database::new(), which resets base timestamps and rebases TTLs before calling
crate::persistence::rdb::save_to_bytes; change the temp creation to preserve the
source guard's base timestamp (e.g., construct temp with the same base timestamp
or call a setter like Database::with_base_timestamp(guard.base_timestamp()) or
temp.set_base_timestamp(guard.base_timestamp())) before copying entries so
is_expired_at/TTL calculations remain consistent; apply the same change to the
other identical snapshot block (the one around lines 835-851) so save_to_bytes
serializes using the original base timestamps rather than a freshly created one.
- Around line 693-712: The snapshot code races with concurrent appends because
it reads each DB via db.iter() using guard.read(), calling base_timestamp() and
data() separately, allowing writes to land in both the captured snapshot and the
incremental AOF; fix by creating an atomic snapshot barrier per database before
collecting entries — either acquire a lock that blocks appends (e.g., upgrade to
a write lock or call a freeze/snapshot API) or switch the append stream to a new
COW/active buffer/generation and then read base_timestamp() and data() from that
frozen generation so entries and base_ts come from the same consistent
generation; look for the snapshot variable, db.iter(), guard.read(),
base_timestamp(), and data() to implement the barrier or buffer-swap solution.
In `@src/persistence/rdb.rs`:
- Around line 729-864: The file is too large; extract the AOF/RDB byte-slice
loader into a submodule by moving load_from_bytes and its related helpers (the
EOF+CRC scanning loop, payload/CRC handling, count_entries_per_db, and any
helper that advances/reads entries like read_entry_zero_copy and scan/skip
helpers) into a new module, make the functions public(crate) or re-exported so
rdb.rs can call them, and replace the in-file implementation with a thin wrapper
that delegates to the new submodule; ensure types used (Database, RdbError,
Hasher, current_time_ms, Bytes) are imported into the new module and update
visibility/signatures so compilation and tests pass.
- Around line 750-754: The EOF+CRC scan can slice past the buffer when fewer
than 4 bytes remain after an EOF_MARKER; update the loop in the scan (the for i
in 5..... block that creates payload and checksum_bytes) to first check that i +
5 <= data.len() (or equivalently that data.len().saturating_sub(i + 1) >= 4)
before taking checksum_bytes = &data[i + 1..i + 5]; alternatively use safe
indexing (get(..)) and bail with a corruption error if the 4 checksum bytes are
not available, ensuring no panics occur on corrupt preambles.
- Around line 332-340: The loader currently catches entry parse errors in the
match arm `Err(e) => { tracing::warn!(...); break; }` (using `cursor.position()`
and `total_keys`) and then returns `Ok(...)`, allowing partial/corrupt snapshots
to be treated as success; change this to propagate a failure instead: replace
the `warn + break` with an early return of an Err constructed with contextual
information (include the offset/cursor.position() and the source error `e`) so
the caller receives a proper error; apply the same fix to the other identical
handler around the second occurrence (the block covering lines ~844-855) so both
loaders fail on corrupt entries rather than returning partial success.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: 8cbdc4dd-bf63-4b12-8387-6b60a1809b7d
📒 Files selected for processing (3)
README.mdsrc/persistence/aof.rssrc/persistence/rdb.rs
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TinDang97
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Apr 8, 2026
Ports the multi-part AOF persistence work from feat/persistence-overhaul (PR #37) as a fresh squash onto post-disk-offload main, dropping the stale branch's obsolete accept-loop / SO_REUSEPORT / cfg-gate changes. Additive content: - src/persistence/aof_manifest.rs — appendonlydir/ manifest + multi-part replay - src/persistence/rdb.rs — save_to_bytes / load_from_bytes + fast bulk loader (count_entries_per_db + Database::reserve + insert_for_load) - src/persistence/aof.rs — writer rewrite: waits for manifest, handles AofMessage::Rewrite{,Sharded} via do_rewrite_{single,sharded}, detects MOON magic prefix for RDB-preamble replay - src/command/persistence.rs — bgrewriteaof_start_sharded - src/storage/compact_value.rs — heap_string_owned / heap_string_vec_direct - src/storage/db.rs — insert_for_load / reserve / recalculate_memory - src/shard/shared_databases.rs — all_shard_dbs() - src/server/conn/handler_{sharded,monoio}.rs — BGREWRITEAOF dispatch - src/main.rs — replay_multi_part layered on v2/v3 recovery, manifest initialized after recovery so the writer thread can unblock Coexistence rule: when appendonlydir/ manifest is present it is authoritative; legacy appendonly.aof fallback (handled by v2 recovery inside restore_from_persistence) only fires when no manifest exists — covering first-upgrade from pre-multi-part moon. Known limitation: multi-part replay is single-shard only; multi-shard clusters log a warning and fall back to v2/v3 recovery. Validation (moon-dev OrbStack, Linux aarch64): cargo fmt --check ok cargo clippy --release -- -D warnings ok cargo clippy --no-default-features --features runtime-tokio,jemalloc -- -D warnings ok cargo test --release --lib 1858 pass cargo test --no-default-features --features runtime-tokio,jemalloc --lib 1877 pass Two failures in cargo test --release --lib (test_inline_set, test_inline_set_with_aof) and tests/replication_test.rs reproduce on clean main — pre-existing, not introduced by this change.
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Superseded by #63, which ports the multi-part AOF + BGREWRITEAOF + fast RDB loader as a fresh squash onto post-disk-offload main and fixes six correctness issues found in review (including a P0 double-apply bug in the rewrite ordering). This branch was 247 commits behind main and rebasing was infeasible. |
pilotspacex-byte
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Apr 9, 2026
* feat: multi-part AOF + BGREWRITEAOF monoio + RDB loader 3x Ports the multi-part AOF persistence work from feat/persistence-overhaul (PR #37) as a fresh squash onto post-disk-offload main, dropping the stale branch's obsolete accept-loop / SO_REUSEPORT / cfg-gate changes. Additive content: - src/persistence/aof_manifest.rs — appendonlydir/ manifest + multi-part replay - src/persistence/rdb.rs — save_to_bytes / load_from_bytes + fast bulk loader (count_entries_per_db + Database::reserve + insert_for_load) - src/persistence/aof.rs — writer rewrite: waits for manifest, handles AofMessage::Rewrite{,Sharded} via do_rewrite_{single,sharded}, detects MOON magic prefix for RDB-preamble replay - src/command/persistence.rs — bgrewriteaof_start_sharded - src/storage/compact_value.rs — heap_string_owned / heap_string_vec_direct - src/storage/db.rs — insert_for_load / reserve / recalculate_memory - src/shard/shared_databases.rs — all_shard_dbs() - src/server/conn/handler_{sharded,monoio}.rs — BGREWRITEAOF dispatch - src/main.rs — replay_multi_part layered on v2/v3 recovery, manifest initialized after recovery so the writer thread can unblock Coexistence rule: when appendonlydir/ manifest is present it is authoritative; legacy appendonly.aof fallback (handled by v2 recovery inside restore_from_persistence) only fires when no manifest exists — covering first-upgrade from pre-multi-part moon. Known limitation: multi-part replay is single-shard only; multi-shard clusters log a warning and fall back to v2/v3 recovery. Validation (moon-dev OrbStack, Linux aarch64): cargo fmt --check ok cargo clippy --release -- -D warnings ok cargo clippy --no-default-features --features runtime-tokio,jemalloc -- -D warnings ok cargo test --release --lib 1858 pass cargo test --no-default-features --features runtime-tokio,jemalloc --lib 1877 pass Two failures in cargo test --release --lib (test_inline_set, test_inline_set_with_aof) and tests/replication_test.rs reproduce on clean main — pre-existing, not introduced by this change. * fix(aof): correctness issues in multi-part rewrite and manifest loading Addresses senior-rust-engineer review of #63. Six fixes across P0/P1: 1. AofManifest::load returns Result<Option<Self>, io::Error> Previous silent-None-on-corruption caused main.rs to call initialize() and overwrite the corrupt manifest, destroying the reference to the real base RDB and losing all persisted data. Corrupt manifest is now fatal at startup. 2. Orphan cleanup on manifest load Scans appendonlydir/ for stray moon.aof.{N}.{base.rdb,incr.aof, *.tmp} with N != current seq and deletes them. Previously a crash between advance() phases 1-3 left zombie base RDBs that never got referenced by any manifest, filling disk over repeated failures. 3. replay_incr_resp: fail-hard on parse error Previous impl did buf.split_to(1) + scan for next '*' byte, silently dropping runs of corrupt commands. '*' can legitimately appear inside bulk-string payloads, so resync was unsound. Recovery of a corrupt incr log is now an error, not silent data loss. 4. Rewrite ordering: drain + lock + snapshot + drain P0 bug: non-idempotent commands (INCR, LPUSH, SADD, ZADD, HINCRBY, APPEND, etc.) were double-applied on recovery after BGREWRITEAOF. The handler applies the write to the DB synchronously, then sends an AofMessage::Append asynchronously. During rewrite, appends queue in the channel while the writer thread is in do_rewrite_*. After rewrite, queued appends are processed into the NEW incr. If the write happened BEFORE the snapshot captured its shard, the write is both in base AND in new incr → replay double-applies. Fix: in do_rewrite_single/sharded, (a) drain the channel to the old incr and fsync, (b) acquire write locks on all (shard, db) pairs simultaneously, (c) drain once more to catch appends completed between step a and step b, (d) snapshot under the locks, (e) release locks, (f) write new base + advance manifest + reopen. Invariant: any write captured in the new base is NOT in the new incr (handlers were blocked), and any write NOT in the new base IS in the new incr (queued after lock release). Creates a brief global write pause during snapshot — acceptable cost for correctness. 5. AOF writer honors corrupt-manifest error Writer thread exits with a loud log instead of spinning on load() forever when the manifest is corrupt, so server startup fails fast. 6. Database::reserve debug_assert empty table Previous impl silently replaced the DashTable regardless of current contents — caller who misused reserve() on a populated database would lose all data without warning. Debug assertion catches the misuse in tests. Validation (moon-dev OrbStack): cargo fmt --check ok cargo clippy --release -- -D warnings ok cargo clippy --no-default-features --features runtime-tokio,jemalloc -- -D warnings ok cargo test --release --lib 1858 pass (test_inline_set* pre-existing failures on main, unrelated) * fix(aof): legacy upgrade double-replay, base rdb fsync, missing-base guard Addresses four real issues from PR #63 review (qodo + coderabbit). Three were P0/P1 correctness bugs; one is correctness-adjacent. 1. Legacy AOF double-replay on upgrade (qodo #2 / coderabbit critical) On first upgrade from legacy single-file AOF, restore_from_persistence replays appendonly.aof into the databases, then main.rs used to call initialize() which created an empty manifest (no base). On the NEXT boot the multi-part replay path ran clear() and then had nothing to load → all legacy state lost. Additionally the legacy file remained on disk, so v2 recovery kept replaying it on subsequent boots, double-applying on top of whatever multi-part state existed. Fix: at first upgrade, if restore_from_persistence loaded any state, serialize it via rdb::save_to_bytes and create the manifest with a real base seq 1 via AofManifest::initialize_with_base(). Rename the legacy appendonly.aof to appendonly.aof.legacy so v2 recovery on the next boot can't find it. Also retire the legacy file after a successful replay_multi_part for the second-boot case. 2. Base RDB not fsynced before manifest publish (qodo #6) AofManifest::advance used std::fs::write + rename, which renames an open file whose contents aren't guaranteed to be on disk. A crash after the manifest write could publish a seq pointing at a base whose contents weren't durable. Fix: explicit File::create + write_all + sync_data + rename. Same pattern applied to initialize_with_base. 3. Multi-part replay clears databases before loading Prevents the double-apply of non-idempotent commands from any state that earlier recovery phases (WAL, legacy AOF) may have loaded. The multi-part AOF is the authoritative source. 4. Missing base + non-empty incr is now an error (coderabbit minor) Previously warned and continued, which would apply deltas on empty state. Now returns an error. Empty-incr case (fresh initialize) is still tolerated. Already addressed in earlier commits (noted in review): - coderabbit: infinite busy-wait on missing manifest — ca2ec51 - coderabbit: silent corruption skip in replay_incr_resp — ca2ec51 - qodo #3: monoio manifest wait can hang on corrupt — ca2ec51 - qodo #4: corrupt manifest reinitialized — ca2ec51 Validation on moon-dev (Linux aarch64): cargo fmt --check ok cargo clippy --release -- -D warnings ok cargo clippy --no-default-features --features runtime-tokio,jemalloc -- -D warnings ok cargo test --release --lib 1858 pass Manual smoke tests passed: 1. BGREWRITEAOF with mixed R/W load — seq advanced, manifest correct 2. Crash-recovery kill -9 mid-rewrite — 3000/3000 keys recovered 3. Double-apply regression: 2000 concurrent INCRs during BGREWRITEAOF — base had snapshot state, incr had remainder, restart counter=2000 4. First-upgrade from legacy appendonly.aof — state captured as base seq 1, legacy file retired, all keys survive next boot without BGREWRITEAOF 5. Corrupt manifest (seq 0) — server refuses to start with clear error * chore(rdb): remove dead zero-copy plumbing Addresses the last two cosmetic PR #63 comments: - qodo: #[allow(dead_code)] on read_bytes_zero_copy lacked justification - coderabbit: unnecessary Bytes::copy_from_slice(data) full-buffer copy fed into read_entry_zero_copy's ignored _shared_buf parameter The "zero-copy" path through read_entry_zero_copy was never actually zero-copy — read_bytes_zero_copy was defined but never called, and read_entry_zero_copy ignored the buffer it was given. This commit: - Deletes read_bytes_zero_copy (truly dead) - Removes the unused _shared_buf parameter from read_entry_zero_copy - Removes the Bytes::copy_from_slice(data) allocation in load_from_bytes that existed solely to feed that parameter - Updates the two call sites - Documents the rationale so a future zero-copy revival adds the plumbing as part of a landed change, not as vestigial code No behavior change; smaller binary, one fewer full-buffer allocation on RDB load_from_bytes. Validation (moon-dev): cargo fmt --check ok cargo clippy --release -- -D warnings ok cargo clippy --no-default-features --features runtime-tokio,jemalloc -- -D warnings ok * fix(rdb): load into temp databases then swap, preventing stale key survival An RDB file (both standalone .rdb and AOF RDB-preamble) is a full point-in-time snapshot. Loading it must replace the in-memory state, not merge into it. Previously both rdb::load() and rdb::load_from_bytes() called insert_for_load() directly on the live databases, so keys that existed before the load but were absent from the RDB snapshot silently survived — producing mixed state. Fix: both load paths now create temporary Database instances, load entries into them, then swap the temps into the live slots on success. This provides: - Correctness: old keys not in the snapshot are gone after load. - Atomicity: if the load fails partway, original state is untouched. - Consistent metadata: recalculate_memory runs on temps before swap, so used_memory reflects exactly the loaded state. The swap is safe w.r.t. cold_index/cold_shard_dir because main.rs initializes those fields after restore_from_persistence completes. Validation (moon-dev): cargo fmt --check ok cargo clippy --release / --runtime-tokio,jemalloc ok cargo test --release --lib 1858 pass Manual: 150 keys through BGREWRITEAOF + incr + restart PASS * fix(aof,rdb): manifest validation, RDB error propagation, CRC O(n), writer timeout Four fixes from code review: 1. aof_manifest::load — validate base/incr records before orphan cleanup A truncated manifest containing only "seq 2" (no base/incr lines) would pass the seq > 0 check, then cleanup_orphans would delete files matching the PREVIOUS valid seq — destroying the actual recovery data. Now load() requires all three records (seq, base, incr) to be present. Truncated manifests return Err, which callers already treat as fatal. 2. rdb::load + rdb::load_from_bytes — return Err on corrupted entries Both load paths now load into temp_dbs, but on Err from read_entry_zero_copy they used to break and fall through to the swap, committing partially-loaded temp databases into live state. Now both paths return Err immediately, leaving live databases untouched. The error includes byte offset and key count for diagnosis. 3. rdb::load_from_bytes — single-pass CRC scan (O(n) vs O(n²)) The EOF_MARKER search was re-hashing data[0..=i] from scratch for each candidate byte. Now maintains a running crc32fast::Hasher updated byte-by-byte, cloning at each candidate position. On a 10MB RDB preamble with k candidates, this reduces from O(n*k) hash bytes to O(n) total. 4. aof::aof_writer_task — bound manifest wait with cancel + timeout The monoio writer's manifest wait loop now checks the CancellationToken each iteration and enforces a 60s hard timeout. Previously if main.rs failed to create the manifest (disk full, permission error), the writer would spin forever, blocking graceful shutdown. Now exits cleanly with a diagnostic log. Skipped: rdb.rs submodule split (1726 lines, above 1500 limit but high-risk churn for a correctness PR — tracked for follow-up). Validation (moon-dev): cargo fmt --check ok cargo clippy --release / --runtime-tokio,jemalloc ok cargo test --release --lib 1858 pass Smoke: 700 keys + INCR counter through BGREWRITEAOF + restart PASS
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Summary
Major persistence overhaul: multi-part AOF format (Redis 7+ compatible), crash recovery, BGREWRITEAOF for monoio, and 3x faster RDB loading.
appendonlydir/withbase.rdb+incr.aof+ manifest (matches Redis 7+ format)Benchmarks (AOF everysec, 1 shard, monoio)
RDB load: 632K keys in 107ms = 5.9M keys/sec
Test plan
Summary by CodeRabbit