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126 questions, 454 terms and 400 topics in 20 areas.
23 results for “Deciding Under Uncertainty”
Decision-Making Under Uncertainty
Choosing well when the information is incomplete — by bounding the downside and buying information, rather than by waiting for certainty.
Admission Control
Deciding at the edge whether to accept a request at all, based on current capacity, before any work is done on it.
Authorization
Deciding whether an authenticated principal may perform a specific action on a specific resource.
Backpressure
A mechanism by which a component under load tells its callers to slow down, rather than accepting work it cannot complete.
Brownout
Deliberately reducing the quality or completeness of every response under load, rather than serving some requests fully and rejecting others.
Capacity Planning
Deciding in advance how much capacity will be needed, given growth, seasonality and failure scenarios, and ensuring it can be there in time.
Image Registry
The store from which container images are pulled, and an under-appreciated availability and security dependency of every deployment and every autoscale event.
Join Strategies
The three ways a database combines two row sets — nested loop, hash join and merge join — and the conditions under which each is correct.
Slowly Changing Dimension
A strategy for handling attributes that change over time, deciding whether history is preserved and how facts attach to the correct version.
Solution Architecture
The design of a specific system that satisfies a specific business problem under a specific set of constraints.
A serverless API works in testing and fails under load with connection errors. The database is at 5% CPU. Explain and fix.
The mechanism Serverless functions scale by creating independent execution environments , each with its own process and its own connection pool. Two hundred con
Classify DynamoDB, Spanner and Cassandra under PACELC, and say which half of the classification you would actually design around.
The classifications Store Partition Else Why DynamoDB (default reads) PA EL Serves from any replica; eventually consistent reads avoid a quorum round trip Cassa
Users report seeing stale data intermittently. Replication lag is normally under a second but spikes to minutes twice a day. How do you handle it?
First: find the cause of the spikes Twice a day is a schedule, so look for one. The usual candidates, each with a different fix: A batch job or bulk write on th
When should a service call another synchronously, and when should it publish an event instead? Give me the deciding test, not a preference.
The deciding test Does this user action succeed or fail based on this callee's response? If yes, the call is synchronous, because you need the answer to decide.
Your cluster fails over spuriously under load, but a real leader failure takes 45 seconds to detect. How do you resolve the tension?
The tension Detection time is set by the heartbeat interval times the failure threshold. Shorten it and you detect real failures faster and mistake slow but ali
You must choose a data store this week. The product team cannot tell you the expected query patterns or the growth rate. What do you do?
What the interviewer is testing How you behave when the information you would like does not exist — which is the normal condition, not the exception. Both "refu
Deciding Under Uncertainty
Bounding the downside and buying information cheaply.
Judgement Under Uncertainty
Choosing the best worst case when information is missing.
Application Rationalisation
Retire, consolidate, replatform — and why retirement is under-applied.
Dashboards
Answering 'is it us' in under a minute, for someone who was asleep.
Degradation Modes
Deciding in advance what is shed first and what is protected.
Estimation
Sizing work and cost honestly, with the uncertainty stated.
Legacy Assessment
Understanding what a system does before deciding what to do with it.