dkv-server

An embedded Redis-protocol server backed by dkv (this repo's embedded KV store), using a master/sub-reactor design:

• Master reactor: epoll only for accept(), then dispatches connection fds to sub-reactors.
• Sub-reactors: one epoll per thread, handles socket I/O + RESP parsing + task dispatch.
• Worker pool: runs dkv operations and posts responses back to the owning sub-reactor.

Build

# from repo root
cmake -S . -B build -DDKV_BUILD_SERVER=ON
cmake --build build -j

Run

./build/dkv-server --data-dir ./dkv-data --bind 0.0.0.0 --port 6379 --subreactors 4 --workers 8

Quick check with redis-cli:

redis-cli -p 6379 PING
redis-cli -p 6379 SET k v
redis-cli -p 6379 GET k

Supported Commands (RESP2 subset)

• PING [message]
• ECHO <message>
• GET <key>
• SET <key> <value>
• DEL <key> [key ...]
• EXISTS <key> [key ...]
• MGET <key> [key ...]
• MSET <key> <value> [key value ...]
• INCR <key>
• INCRBY <key> <increment>
• DECR <key>
• DECRBY <key> <decrement>
• QUIT
• HELLO (minimal reply)
• INFO (minimal reply)
• COMMAND (returns empty array)
• CLIENT SETINFO ... (accepted; returns OK)
• CONFIG GET <pattern> (exposes server + dkv config, e.g. CONFIG GET *, CONFIG GET data-dir)
• CONFIG RESETSTAT, CONFIG REWRITE (returns OK)
• METRICS / METRIC (returns dkv::Metrics as an array of key/value pairs)
• FLUSH (forces db->Flush())
• COMPACT (forces db->Compact())

Unsupported commands return -ERR unknown command.

Iterator / Scan Commands

These commands expose dkv::DB::Iterator over RESP for debugging and admin workflows.

• SCAN [prefix] -> returns [iter_id, valid, key, value]
• SEEKTOFIRST <iter_id> -> returns [valid, key, value]
• SEEK <iter_id> <target> -> returns [valid, key, value]
• NEXT <iter_id> -> returns [valid, key, value]
• VALID <iter_id> -> returns 0 or 1
• ITERDEL <iter_id> -> closes the iterator (frees memory)

Notes:

• The iterator is a point-in-time view built when SCAN runs (not a live cursor).
• key/value are returned as RESP bulk strings; if valid=0, both are nil.

Configuration

All dkv::Options fields are exposed as CLI flags (see include/dkv/options.h).

Notes:

• *-bytes options accept plain integers (bytes) and also K|KB, M|MB, G|GB suffixes (base 1024).
• Boolean options accept true/false/1/0/yes/no/on/off. Passing the flag without a value means true.

Server flags

• --bind <ip> (default 0.0.0.0)
• --port <port> (default 6379)
• --subreactors <n> (0 = auto)
• --workers <n> (0 = auto)

dkv flags

• --data-dir <path>
• --memtable-soft-limit-bytes <bytes>
• --sync-wal [bool]
• --sstable-target-size-bytes <bytes>
• --sstable-block-size-bytes <bytes>
• --bloom-bits-per-key <n>
• --bloom-cache-capacity-bytes <bytes>
• --raw-block-cache-capacity-bytes <bytes>
• --block-cache-capacity-bytes <bytes>
• --level0-file-limit <n>
• --level-base-bytes <bytes>
• --level-size-multiplier <n>
• --max-levels <n>
• --flush-thread-count <n>
• --max-immutable-memtables <n>
• --compaction-thread-count <n>
• --wal-sync-interval-ms <ms>
• --enable-crc [bool]
• --verify-sstable-crc [bool]
• --enable-compress [bool] (requires dkv built with a compression backend)

On-disk Layout

All persistent files live under --data-dir:

• wal.log: active WAL
• wal-*.log: rotated WAL segments
• MANIFEST: manifest file
• sst/: SSTable files