perf(redis): keep JSON serialization on UTF-8 bytes instead of UTF-16 strings - #88
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… strings JSON is UTF-8 on the wire, so round-tripping cache payloads through a UTF-16 string only added an allocation + transcode on every read and write. This moves the serialization boundaries to bytes (enabled by StackExchange.Redis 3.0's RedisValue <-> ReadOnlyMemory/ReadOnlySequence<byte> conversions). - SystemJsonSerializerProxy: serialize via SerializeToUtf8Bytes; deserialize from the RedisValue payload as ReadOnlySpan<byte>. Also deserialize a JsonElement directly instead of via GetRawText(). Shared by RedisCache, RedisHashCache, RedisSetCache, RedisCacheProvider, so all inherit the win. - Broadcast: CacheEventFormatter.Encode uses SerializeToUtf8Bytes; the Redis publish paths (RedisPubSubTopic, RedisStreamsTopic) publish the encoded bytes as a RedisValue directly; the subscribe paths (RedisPubSubSubjectWriter, RedisStreamSubjectWriter) decode from the RedisValue bytes. - Deprecate the now-unused string helpers IEventFormatterProxy<T>.Decode(string) and EncodeAsString(T); migrate the stream-subject-writer tests to the ReadOnlyMemory<byte> overload. Wire format is unchanged everywhere, so existing cached/published data still deserializes. No public API change beyond the two [Obsolete] markers. Measured with a new SerializerBenchmark ([MemoryDiagnoser]): ~2x fewer allocations on serialize/deserialize (e.g. large-payload deserialize 1,385,629 B -> 607,714 B; serialize 778,689 B -> 389,660 B) with equal-or-better throughput. The benchmark also compared a ReadOnlySequence<byte>/Utf8JsonReader read variant; it allocated the same as the span path but ran slower on these single-segment payloads, so the span path was chosen. Full suite green on net8.0 and net10.0 (1178/1178 each). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Signed-off-by: Cosmin Staicu <cosmin.staicu@uipath.com>
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Summary
JSON is UTF-8 on the wire, but the cache serializer round-tripped every payload through a UTF-16
string, adding an allocation + transcode on every read and write. This keeps serialization on UTF-8 bytes end-to-end, enabled by StackExchange.Redis 3.0'sRedisValue↔ReadOnlyMemory/ReadOnlySequence<byte>conversions. No public API change beyond two[Obsolete]markers; wire format is unchanged so existing cached/published data still deserializes.Changes
SystemJsonSerializerProxy(the default proxy, shared byRedisCache,RedisHashCache,RedisSetCache,RedisCacheProvider— all inherit the win): serialize viaSerializeToUtf8Bytes; deserialize from theRedisValuepayload asReadOnlySpan<byte>; deserialize aJsonElementdirectly instead of viaGetRawText().CacheEventFormatter.EncodeusesSerializeToUtf8Bytes; the publish paths (RedisPubSubTopic,RedisStreamsTopic) publish the encoded bytes as aRedisValuedirectly; the subscribe paths (RedisPubSubSubjectWriter,RedisStreamSubjectWriter) decode from theRedisValuebytes.IEventFormatterProxy<T>.Decode(string)andEncodeAsString(T)(now unused by the library — they forced a UTF-16 transcode). Stream-subject-writer tests migrated to theReadOnlyMemory<byte>overload.Benchmark
New
SerializerBenchmark([MemoryDiagnoser]). Allocation numbers are exact/reliable; roughly halved on both paths:The benchmark also measured a
ReadOnlySequence<byte>/Utf8JsonReaderread variant; it allocated identically to the span path but ran slower on these single-segment payloads, so the span path was chosen. (Run:dotnet run -c Release --framework net10.0 --project benchmarks/UiPath.Caching.Benchmarks -- --filter *SerializerBenchmark*)Test plan
SystemJsonSerializerProxyTestsincl. legacy string-path round-trip; broadcast tests migrated)dotnet test)Full suite green on net8.0 and net10.0 — 1178/1178 each — with
RUN_REDIS_INTEGRATION_TESTS=1against a live Redis.Linked issues
Fixes #
Contributor declaration
git commit -s).🤖 Generated with Claude Code