Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
19 results for “Vector Databases”
Vector Database
A store optimised for approximate nearest-neighbour search over high-dimensional embeddings.
Version Vector
A per-replica counter set that lets a system tell whether one version causally descends from another or whether the two are genuinely concurrent.
Block Storage
A virtual disk attached to one instance at a time, presented as raw blocks and formatted with a filesystem — the storage databases and stateful workloads run on.
Connection Pool
A fixed set of reusable database connections shared by an application's requests, and one of the most common hidden capacity ceilings.
Connection Proxy
A pooling layer between applications and a managed database that multiplexes many client connections onto a small number of database connections.
Database Index
A secondary structure that lets the engine find rows without scanning, trading write cost and storage for read speed.
Embedding
A dense numeric vector representing a piece of content, positioned so that semantically similar content sits nearby.
Indexing Strategy
Choosing the set of indexes a table carries by working backwards from its actual queries, and accepting the write cost that each one adds.
Provisioned vs Serverless Capacity
Paying for a fixed database size continuously, versus paying for capacity consumed with automatic scaling — a crossover decision driven by duty cycle.
Query Plan
The database's chosen strategy for executing a query, and the first thing to look at when one is slow.
Read Replica
A copy of a database that receives changes from the primary and serves read-only queries, spreading read load.
SQL vs NoSQL
A choice driven by access patterns, consistency requirements and query flexibility — not by data volume, which is the reason usually given.
Sharding
Splitting one dataset across multiple independent databases by a partition key, so that each holds a disjoint subset.
Write-Ahead Log
Recording every change to a durable sequential log before applying it, so that a crash can be recovered by replaying the log.
Four services want four different databases: Postgres, MongoDB, Cassandra and Neo4j. What do you say?
The response: make each team justify it against a default Polyglot persistence is legitimate and routinely over applied. The question for each is not "is this d
A dashboard query that took 200ms now takes 40 seconds. The table has grown to 200 million rows. Walk me through diagnosis and fix, including what you would not do.
What the interviewer is testing Whether you diagnose with evidence before changing anything, and whether you know the costs of the fixes you propose. Diagnosis,
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