- Implemented only for the structured cache initially.
- Records are stored as compact binary packages with payloads stored within the record if small enough.
- Records are stored in Records/{Bucket}/{01}/{23}/{456789abcdef0123456789abcdef01234567} based on the hash in the cache key.
- Content that exceeds the size allowed for storage within the record is stored in Content/{01}/{23}/{456789abcdef0123456789abcdef01234567} based on the hash of the content.
- Both records and content are written to disk with their hash as a suffix, and are always checked on load.
- Maximum size of compressed data stored in the package can be configured by MaxRecordSizeKB and MaxValueSizeKB.
- Maintenance of the cache, to delete unused files, has been rewritten and can now scan ~175k files/second on modern hardware, though is limited to 10k files/second in the config to avoid adding too much overhead.
#rb Zousar.Shaker
#preflight 618b75c14a0c609a29204032
#preflight 618bfb5ec717ba4e929b7ac0
#ROBOMERGE-AUTHOR: devin.doucette
#ROBOMERGE-SOURCE: CL 18133085 in //UE5/Release-5.0/... via CL 18133356
#ROBOMERGE-BOT: STARSHIP (Release-Engine-Staging -> Release-Engine-Test) (v889-18060218)
#ROBOMERGE[STARSHIP]: UE5-Main
[CL 18133430 by devin doucette in ue5-release-engine-test branch]
- ICacheStore::Put() has updated documentation to reflect the requirements of partial records.
- ICacheStore::Get() now takes a FCacheRecordPolicy, which is implicitly constructible from ECachePolicy, and allows setting the policy by payload.
- ICacheStore::GetPayload() is replaced by ICacheStore::GetChunks(), which allows loading parts of payloads.
- ICacheStore::CancelAll() is moved to ICache::CancelAll() because the cache can track requests at the top level and cancel them without exposing cancellation on individual cache stores.
- ECachePolicy::SkipLocalCopy has been removed because it is difficult to reason about.
- ECachePolicy::SkipData flags now have a documented meaning for put requests, to hint that record existence implies payload existence.
- The filesystem and memory cache stores have been updated to support partial records, filtering of payloads, and loading parts of payloads.
- Requesting part of a payload will decompress the entire payload for now, until compressed buffers expose a way to decompress only part.
- Fixed a bug in FTexturePlatformData::AreDerivedMipsAvailable() that caused it to return false for structured cache keys.
#rb Zousar.Shaker
#rnx
#preflight 615e03241ed62f0001b95454
#ROBOMERGE-OWNER: Devin.Doucette
#ROBOMERGE-AUTHOR: devin.doucette
#ROBOMERGE-SOURCE: CL 17748550 in //UE5/Release-5.0/... via CL 17748555
#ROBOMERGE-BOT: STARSHIP (Release-Engine-Staging -> Release-Engine-Test) (v879-17706426)
#ROBOMERGE-CONFLICT from-shelf
#ROBOMERGE[STARSHIP]: UE5-Main
[CL 17748602 by Devin Doucette in ue5-release-engine-test branch]
FCacheBucket is now always exposed as FAnsiStringView.
#rb Zousar.Shaker
#rnx
#ROBOMERGE-SOURCE: CL 17084521 in //UE5/Main/...
#ROBOMERGE-BOT: STARSHIP (Main -> Release-Engine-Test) (v853-17066230)
[CL 17084549 by devin doucette in ue5-release-engine-test branch]
- Identify payloads by the hash of the raw data.
- Added FCacheKey::Empty and FCachePayloadKey::Empty for convenience.
- Changed FCacheRecord and FCacheRecordBuilder constructors to be private.
- Changed storage in the legacy cache to store values inline for records with no attachments.
- Changed storage in the legacy cache to use CAS within each bucket.
- Improved wording and details in assert messages.
#rb Zousar.Shaker
#rnx
[CL 15984411 by Devin Doucette in ue5-main branch]
- Removed the "Cache" prefix from ECachePriority, FCacheRequest, ICacheRequest, FCachePayload, FCachePayloadId to allow reuse in the Build API.
- Added FCompressedBuffer as the starting point for the API for creating and accessing compressed buffers.
#rb Zousar.Shaker
#rnx
[CL 15511723 by Devin Doucette in ue5-main branch]
- FCacheRecord must now be created by FCacheRecordBuilder.
- FCacheRecord values are always an opaque buffer now, and ECacheRecordType has been removed.
- FCachePayload has been added as a common type for the cache record value and attachments.
- FCachePayloadId has been added as a 12-byte identifier for cache payloads.
- ICache::GetAttachments is now GetPayloads and can fetch both values and attachments.
- ECachePriority::Blocking has been added for requests that the caller will block on.
#rb Zousar.Shaker
#rnx
[CL 15471951 by Devin Doucette in ue5-main branch]
ICache will eventually replace the existing cache access functions on FDerivedDataCacheInterface. The notable differences relative to the existing interface are:
- It is asynchronous with completion callbacks by default, and allows waiting when necessary.
- It allows batch requests containing multiple cache records by default.
- It uses a structured cache key made up of a bucket name and a hash.
- It supports prioritization and cancellation of requests.
- It supports structured cache records with metadata.
- It supports attachments to allow multi-part cache records.
- It uses a typed request object instead of an opaque integer handle.
- It provides cache policy flags to control how to query and store cache records, and which parts of a cache record to fetch.
This initial implementation of ICache is totally synchronous and uses the existing cache backends for storage.
#rb Zousar.Shaker
[CL 15152247 by Devin Doucette in ue5-main branch]
