Coalesce concurrent download requests for the same object#1929
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tyrielv merged 1 commit intomicrosoft:masterfrom Apr 1, 2026
Merged
Coalesce concurrent download requests for the same object#1929tyrielv merged 1 commit intomicrosoft:masterfrom
tyrielv merged 1 commit intomicrosoft:masterfrom
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Adds a ConcurrentDictionary<string, Lazy<DownloadAndSaveObjectResult>> to GVFSGitObjects so only one download runs per objectId at a time. Concurrent callers share the result via the Lazy<T> pattern. The entry is removed after completion using value-aware removal (ICollection<KVP>.Remove) to prevent an ABA race where a straggling thread's finally could remove a newer Lazy created by a later wave of requests. Assisted-by: Claude Opus 4.6 Signed-off-by: Tyrie Vella <tyrielv@gmail.com>
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KeithIsSleeping
approved these changes
Mar 31, 2026
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Problem
Under memory pressure, multiple git.exe processes request the same loose object via named pipes simultaneously. Each request triggers an independent HTTP download — the incident log showed 48,176 events with zero available connections, caused by redundant downloads of the same SHAs.
Change
Adds a
ConcurrentDictionary<string, Lazy<DownloadAndSaveObjectResult>>toGVFSGitObjectsso only one download runs per objectId at a time. Concurrent callers share the result. Entry is removed after completion so subsequent requests get fresh attempts.Key review areas
GetOrAddandTryRemoveinfinally)Testing
3 new unit tests: concurrent coalescing, independent SHAs not coalesced, failed download allows retry.