Removed .with_for_update() from _replace_applications() which was
acquiring row-level locks on every collector check-in (800/hour).
These locks were holding during fingerprint comparison, blocking
concurrent reads and causing severe performance degradation.
The UNIQUE constraint on (assetid, app_fingerprint) already provides
sufficient concurrency protection without explicit row locks.
Impact: Eliminates 800 lock acquisitions per hour, unblocks reads
during check-in processing.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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