Topic: This implementation has no snapshotting or log truncation — consider how the log grows unboundedly and what a compaction extension would require

Date: 2026-05-29

Time: 13:52

I have enough from the observations to give a thorough explanation. Let me work with what's already gathered.

Topics to Explore

[function] raft-consensus/raft.py:makeappend_entries — See how the full log suffix is sliced for replication; this is the hot path that snapshots would optimize
[function] raft-consensus/raft.py:handleappendentries — The log consistency check indexes directly into self._log, which would break after truncation
[file] write-ahead-log/wal.py — Compare its truncate() and _rotate() methods as patterns for log lifecycle management
[file] log-structured-merge-tree/lsm.py — The compact() method shows a complete compaction implementation with tombstone removal in this same codebase
[general] raft-installsnapshot-rpc — The Raft paper's Section 7 describes the InstallSnapshot RPC that would complement log truncation

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raft-log-never-shrinks — self._log in RaftNode is append-only: no method ever removes entries, so it grows monotonically with client requests
raft-log-direct-indexed — Log entries are accessed by log index as a direct array index (self.log[prevlog_index]), which assumes all entries from index 0 onward are present in memory
raft-no-state-machine-apply — lastapplied is tracked but never used to actually apply commands to a state machine, making snapshotting impossible without first implementing application logic
wal-has-truncation-raft-does-not — The WAL module provides explicit truncate(uptoseq) and file rotation; the Raft module has no equivalent, despite both being append-only log abstractions
raft-sentinel-entry-assumption — The log is initialized with a sentinel LogEntry(term=0, index=0) at position 0, and multiple methods depend on this entry always being present at self._log[0]