A Lambda function's Throttles metric spikes during traffic bursts, and invocations get dropped. What's the direct fix — and which approach is a common mistake?
A.Increase function memory
Memory speeds execution but doesn't raise the concurrency ceiling.
B.Raise the concurrency limit (or request a quota increase); reserved concurrency on OTHER functions can also starve this one
Correct. Throttles are a concurrency problem — solve at the quota/pool level.
C.Add a reserved concurrency cap to this function
A cap on THIS function makes throttling worse, not better — the trap.
D.Increase the timeout
Timeout affects duration, not concurrent capacity.
Why this answer
Throttles = concurrency exhausted. Fix: raise account/regional concurrency quota or free it up — and note that over-reserving concurrency on other functions subtracts from the shared pool. Memory/timeout don't create more concurrent capacity.
Correct answer: B · Last reviewed 2026-10-26
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