fix(memory): open sqlite db under file lock to avoid SQLITE_BUSY races#3538
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In ensureDB, OpenDB was called before acquiring the file lock; the first open of a fresh database converts it to WAL mode which needs an exclusive lock not covered by busy_timeout, so concurrent first-opens could race. Moving lock acquisition before OpenDB ensures open + WAL conversion + schema migration all run under the lock. Assisted-By: Claude
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Jul 8, 2026
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TestConcurrentAddsPreserveAllRowswas flaky, failing withdatabase is locked (5) (SQLITE_BUSY), reliably reproducible withgo test -run TestConcurrent -count=10 -race ./pkg/memory/database/sqlite/. The root cause was inMemoryDatabase.ensureDB:sqliteutil.OpenDBwas called before acquiring the advisory file lock. Opening pings the database and thejournal_mode(WAL)DSN pragma converts a fresh database to WAL mode; that conversion needs an exclusive lock and is not retried bybusy_timeout. With multiple workers opening the same brand-new file concurrently, first-open attempts raced and whole workers failed.The fix moves the
OpenDBcall to after the file lock is acquired, so the open, WAL conversion, and schema migration all happen under the lock. The lock is already held for migrations; extending its scope one step earlier costs nothing and eliminates the race entirely.No behaviour changes for existing callers.
TestConcurrent*now passes 30 iterations with-racewhere it previously failed within 10.