branch-3.1: [fix](metacache) Fix query hang caused by Caffeine cache deadlock in external table queries #57856 #58065
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…external table queries (#57856) **Symptom:** External table queries hang indefinitely, FE process frozen. **User-facing impact:** Query threads blocked waiting for schema cache: ``` "mysql-nio-pool-14981" TIMED_WAITING at LinkedBlockingQueue.offer(LinkedBlockingQueue.java:385) at ThreadPoolManager$BlockedPolicy.rejectedExecution(ThreadPoolManager.java:347) at ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1379) at CompletableFuture.asyncSupplyStage(CompletableFuture.java:1618) at CacheLoader.asyncReload(CacheLoader.java:188) at BoundedLocalCache.refreshIfNeeded(BoundedLocalCache.java:1214) at LocalLoadingCache.get(LocalLoadingCache.java:56) at ExternalSchemaCache.getSchemaValue(ExternalSchemaCache.java:86) at ExternalTable.getSchemaCacheValue(ExternalTable.java:371) at HMSExternalTable.getPartitionColumns(HMSExternalTable.java:288) at PruneFileScanPartition.pruneHivePartitions(PruneFileScanPartition.java:84) "CommonRefreshExecutor-63" TIMED_WAITING at LinkedBlockingQueue.offer(LinkedBlockingQueue.java:385) at ThreadPoolManager$BlockedPolicy.rejectedExecution(ThreadPoolManager.java:347) at ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1379) at CompletableFuture.asyncSupplyStage(CompletableFuture.java:1618) at CacheLoader.asyncReload(CacheLoader.java:188) at BoundedLocalCache.refreshIfNeeded(BoundedLocalCache.java:1214) "CommonRefreshExecutor-62" TIMED_WAITING at LinkedBlockingQueue.offer(LinkedBlockingQueue.java:385) at ThreadPoolManager$BlockedPolicy.rejectedExecution(ThreadPoolManager.java:347) at ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1379) at BoundedLocalCache.notifyRemoval(BoundedLocalCache.java:333) at BoundedLocalCache.removeNode(BoundedLocalCache.java:1882) at LocalManualCache.invalidateAll(LocalManualCache.java:150) at MetaCache.invalidateAll(MetaCache.java:121) at ExternalDatabase.setUnInitialized(ExternalDatabase.java:123) ``` **Root cause**: Caffeine cache deadlock when: 1. MetaCache uses bounded executor (CommonRefreshExecutor: 64 threads + 640K queue) for both async operations and removal listeners 2. Database cache removal listener calls tableCache.invalidateAll() 3. Executor is full (all threads busy + queue full) 4. Both async reload and removal listener try to submit tasks to full executor 5. Deadlock: executor threads wait for tasks, tasks wait for executor slots Jstack evidence: 82 CommonRefreshExecutor threads blocked on LinkedBlockingQueue.offer(): **Solution** - Add CacheFactory.buildCacheWithSyncRemovalListener() using Runnable::run executor - MetaCache.metaObjCache uses sync removal listener to avoid executor contention - Removal listener runs inline on calling thread instead of submitting to executor **Changes** - CacheFactory: Add buildCacheWithSyncRemovalListener() and buildCacheWithAsyncRemovalListener() - MetaCache: Use buildCacheWithSyncRemovalListener() for metaObjCache - Add MetaCacheDeadlockTest to verify fix **Test** Unit test reproduces deadlock with async removal listener and verifies fix with sync removal listener.
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Thank you for your contribution to Apache Doris. Please clearly describe your PR:
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run buildall |
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run buildall |
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FE UT Coverage ReportIncrement line coverage |
morningman
approved these changes
Nov 20, 2025
morrySnow
approved these changes
Nov 25, 2025
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Cherry-picked from #57856