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Za darmo · bez rejestracji · bez limitu czasu
Gotowe quizy z pytaniami zamkniętymi, sprawdzone ręcznie. Rozwiąż dowolny darmowy quiz online — każda odpowiedź ma wyjaśnienie, a każdy quiz pełny klucz odpowiedzi do powtórki.
IT
Deep dive into distributed systems engineering, covering consensus protocols (Raft/Paxos), the CAP theorem, and vector clocks. Odpowiadaj na pytania i od razu sprawdzaj, czy to dobra odpowiedź — zawsze z wyjaśnieniem.
Darmowy test próbny z 16 pytaniami zamkniętymi z kategorii IT. Każde pytanie ma jedną poprawną odpowiedź i krótkie wyjaśnienie, a pełny klucz odpowiedzi pod quizem służy jako ściąga do nauki. Bez konta, bez limitu czasu — rozwiązuj, ile chcesz.
To darmowy quiz z 16 pytaniami zamkniętymi. Po każdej odpowiedzi zobaczysz, czy była poprawna, razem z wyjaśnieniem. Bez rejestracji i bez limitu czasu — rozwiązuj go, ile razy chcesz, a klucz odpowiedzi powyżej wykorzystaj do powtórki przed quizem albo po nim.
Poprawna odpowiedź: BChoose between consistency (C) or availability (A)
When network partitions occur, a distributed system must either reject writes/reads to maintain identical state (Consistency) or accept operations and risk divergent data (Availability).
Poprawna odpowiedź: ARandomized election timeouts for each candidate node
Raft uses randomized election timeouts (e.g., 150ms–300ms) so one node times out and initiates an election before others, avoiding split votes.
Poprawna odpowiedź: BWhen network disconnection causes distinct sub-clusters to each believe they are the legitimate leader
Split-brain occurs when a network partition cuts cluster communication, causing nodes on both sides to elect independent leaders and accept conflicting writes, risking corruption.
Poprawna odpowiedź: BThe exact causal relationship and concurrency between distinct distributed events
While Lamport timestamps provide total ordering, vector clocks maintain vector arrays that can differentiate whether two events are causally related or occurred concurrently.
Poprawna odpowiedź: BIf the coordinator crashes permanently after the prepare phase, participants must wait indefinitely for a decision
In 2PC, if participants vote 'yes' and the coordinator fails before broadcasting 'commit' or 'abort', participants cannot independently resolve the transaction and hold locks indefinitely.
Poprawna odpowiedź: BReaching agreement on a single value among a group of unreliable processors over an asynchronous network
Paxos guarantees safety and consensus among distributed nodes communicating over an asynchronous, lossy network, as long as a quorum of non-faulty nodes is reached.
Poprawna odpowiedź: AAll read and write operations appear to take place atomically at a discrete point in time between their invocation and completion
Linearizability ensures that every operation appears to execute atomically at a specific instant between its start and finish, matching the behavior of a single, central copy of data.
Poprawna odpowiedź: BBy utilizing TrueTime API, which leverages GPS receivers and atomic clocks to bound timestamp uncertainty
Google Spanner's TrueTime API provides bounded time uncertainty intervals backed by atomic clocks and GPS, allowing the database to assign monotonic commit timestamps globally.
Poprawna odpowiedź: ATo ensure that read and write operations intersect at least one up-to-date node by satisfying R + W > N
A quorum (strictly majoritarian, or configured such that Read quorum + Write quorum > Total nodes) guarantees that any successful read operation overlaps with at least one node containing the latest write.
Poprawna odpowiedź: BTo efficiently disseminate cluster membership, node state, and failure detection information peer-to-peer
Gossip protocols periodically exchange state metadata between random peer pairs, eventually diffusing cluster membership and node health across the entire network in O(log N) rounds.
Poprawna odpowiedź: AReaching consensus when nodes may not only fail or drop packets, but also send conflicting or malicious messages
The Byzantine Generals Problem models scenarios where actors can act maliciously or deceitfully (arbitrary/Byzantine faults), requiring algorithms like PBFT to guarantee consensus.
Poprawna odpowiedź: AA data structure that can be replicated across nodes and resolved concurrently without coordination or merge conflicts
CRDTs (operation-based or state-based) rely on mathematically commutative and idempotent operations, allowing concurrent updates across replicas to converge to the exact same state without locks.
Poprawna odpowiedź: BClock drift, network jitter, and leap seconds make physical clocks unreliable for strict global ordering
NTP cannot guarantee perfect physical clock synchronization due to network latency, virtualization skew, and clock drift, making reliance on wall-clock time risky for transactional ordering.
Poprawna odpowiedź: BTo distinguish between older, stale leadership reigns and current cluster states
Epoch/term numbers act as logical clocks, allowing nodes to identify and disregard outdated commands or heartbeats emitted by disconnected or partitioned former leaders.
Poprawna odpowiedź: BDuring a read query, the coordinator compares data versions from multiple replicas and asynchronously updates out-of-date nodes
When a client reads data with a high consistency level, the coordinator queries multiple replicas; if it detects stale data, it returns the latest version to the client and writes updates to the stale nodes.
Poprawna odpowiedź: BDeterministic consensus is impossible to guarantee in an asynchronous network if even a single process is subject to unannounced crash failure
The landmark 1985 FLP theorem proved that in a purely asynchronous network, no deterministic consensus protocol can guarantee both safety and liveness if even one node can crash.