perf: use CompactString for keys (SSO ≤24 bytes)#228
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add auth, election, and raft_transport to the modules table and features list. fix emberkv-core typo → ember-core in the related crates table.
hot-path quick wins from performance audit (phase A): - fuse double hash probe on GET/GET_STRING into single lookup that checks expiry inline, eliminating ~2M redundant probes/sec - cache value_size in Entry struct so memory accounting is O(1) instead of walking entire collections on every mutation - shrink last_access from u64 ms to u32 secs, saving 4 bytes/entry and improving cache-line packing for the hot Entry struct - replace allocating peek_command_name (3 heap allocs per MULTI/EXEC command) with zero-allocation eq_ignore_ascii_case comparisons
replace Box<str> with compact_str::CompactString for all keyspace keys. CompactString inlines strings up to 24 bytes on the stack, eliminating heap allocation for the vast majority of real cache keys (e.g. "user:123", "session:abc", "rate:ip:1.2.3.4"). - Box<str>: 16 bytes on stack (ptr + len), always heap-allocates - CompactString: 24 bytes on stack, inlines ≤24 byte strings the extra 8 bytes per key struct is offset by eliminating heap allocation overhead (typically 16-32 bytes per allocation) for short keys. lookups work unchanged since CompactString implements Borrow<str>. ENTRY_OVERHEAD bumped from 120 to 128 to account for the larger key struct.
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summary
Box<str>withcompact_str::CompactStringfor all keyspace keys across keyspace, dropper, concurrent keyspace, and memory trackingENTRY_OVERHEADbumped from 120 → 128 to reflect the larger key struct (24 vs 16 bytes)what was tested
cargo test -p emberkv-core --lib— 345 tests passcargo check -p emberkv-core— clean buildcargo clippy -p emberkv-core --no-deps— no new warnings (8 pre-existing doc_lazy_continuation in sorted_set.rs)design considerations
the 8-byte increase per key struct is more than offset by eliminating heap allocator overhead (16-32 bytes per allocation) for keys under 24 bytes. lookups work unchanged since
CompactStringimplementsBorrow<str>,Hash, andEq. thecompact_strcrate is well-maintained and widely used (~36M downloads).