fts: serialize concurrent mutations of QFTSEdgeCompute scores map - #69
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QFTSEdgeCompute copies share the same scores map by reference (one copy per worker thread in a scheduled parallel frontier task), but edgeCompute mutated the map with no synchronization. Concurrent emplace/at() can rehash the map while other threads mutate it, corrupting the heap. Guard all mutations with a shared mutex, mirroring the existing MatchTermsVertexCompute::resDfsMutex pattern. Related to LadybugDB/ladybug#840.
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Summary
QFTSEdgeCompute::copy()(used to give each worker thread in a scheduled parallel frontier task its own edge compute) shares the samescoresmap by reference, butedgeCompute()mutated it with no synchronization. Concurrentemplace/at()can rehash the map while other threads mutate it, corrupting the heap — observed asmalloc(): invalid next size (unsorted)aborts under concurrentQUERY_FTS_INDEXscans (see LadybugDB/ladybug#840).Guard all mutations with a shared mutex owned via
std::shared_ptrso copies share the same lock, mirroring the existingMatchTermsVertexCompute::resDfsMutexpattern in the same file.Companion PR: LadybugDB/ladybug#845 (bumps the submodule to this commit).