VladRodionov opened a new pull request, #8575:
URL: https://github.com/apache/hbase/pull/8575
## Summary
This PR extends the topology-backed cache access framework so that cache
diagnostics and cache
access are consistently routed through `TopologyBackedCacheAccessService`.
The main change is that plain single-tier `BlockCache` implementations now
use the same
topology-backed access path as combined caches. Single-tier caches are
represented by
`SingleTierTopology`, while existing two-tier cache variants continue to use
topology-specific
representations:
* `BlockCache` -> `SingleTierTopology`
* `CombinedBlockCache` -> `TieredExclusiveTopology`
* `InclusiveCombinedBlockCache` -> `TieredInclusiveTopology`
This keeps the legacy cache implementations underneath through
`BlockCacheBackedCacheEngine`, but
moves the access-service boundary to the topology/cache-engine model.
## Motivation
After HBASE-30305, exclusive combined-cache orchestration was moved behind
`TopologyBackedCacheAccessService`. Follow-up testing showed that diagnostic
and compatibility paths
still had assumptions about `BlockCacheBackedCacheAccessService` and
concrete `BlockCache`
implementations.
This PR removes those assumptions from the main factory path by making
topology-backed access the
normal path for both single-tier and combined caches.
## Changes
* Added `SingleTierTopology`.
* Added `CacheTopologyType.SINGLE_TIER`.
* Added topology-backed factory support for single-tier `BlockCache`
instances.
* Added explicit topology-backed support for `InclusiveCombinedBlockCache`.
* Preserved separate semantics for exclusive and inclusive combined caches:
* exclusive promotion moves a block between tiers;
* inclusive promotion copies a block and keeps the source tier;
* inclusive eviction evicts from all tiers.
* Added cached-block iterable diagnostics through the topology-backed
service.
* Preserved legacy default `cacheBlock(key, block)` behavior for single-tier
caches.
* Added test helpers for unwrapping legacy `BlockCache` instances from
topology-backed services
where tests still need direct compatibility checks.
* Added focused tests for:
* single-tier topology-backed cache access;
* exclusive combined-cache compatibility;
* inclusive combined-cache compatibility.
## Compatibility notes
`BlockCacheBackedCacheAccessService` is no longer the default factory result
for plain block caches.
Instead, the main factory now returns a `TopologyBackedCacheAccessService`
backed by
`SingleTierTopology`.
The underlying legacy `BlockCache` implementations are still preserved
through
`BlockCacheBackedCacheEngine`. This PR does not migrate `LruBlockCache`,
`BucketCache`, or other
concrete cache implementations to native `CacheEngine` implementations yet.
That remains a follow-up
migration step.
## Testing
Focused tests:
```bash
mvn -pl hbase-server \
-Dtest=TestSingleTierTopologyBackedCacheAccessService test
mvn -pl hbase-server \
-Dtest=TestCombinedBlockCacheCompatibleTopologyBackedCacheAccessService
test
mvn -pl hbase-server \
-Dtest=TestInclusiveCombinedBlockCacheCompatibleTopologyBackedCacheAccessService
test
mvn -pl hbase-server \
-Dtest=TestHFile test
mvn -pl hbase-server \
-Dtest=TestBlockCacheReporting test
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