AWS Database flashcards
AWS Database · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Aurora quorum model
- Aurora stores six copies of each segment across three Availability Zones. Writes require a quorum of four copies and reads require three, so an entire AZ can fail without losing write capability.
- DynamoDB item size limit
- A single DynamoDB item, including all attribute names and values, cannot exceed 400 KB. Larger objects belong in S3 with the key stored as an attribute.
- DynamoDB Accelerator (DAX)
- A write-through, in-memory cache that sits in front of DynamoDB and returns item reads in microseconds. It serves eventually consistent reads only and does not support strongly consistent reads.
- Neptune
- A fully managed graph database engine supporting property graphs with Gremlin and openCypher, and RDF with SPARQL. It targets highly connected datasets such as social graphs and fraud detection.
- Redshift distribution styles
- DISTKEY co-locates rows sharing a value on the same node for joins, ALL replicates the whole table to every node for small dimension tables, EVEN spreads rows round-robin, and AUTO lets Redshift choose.
- Redis versus Memcached
- ElastiCache for Redis offers persistence, replication, Multi-AZ failover, and complex data types. Memcached is multithreaded but has no persistence, replication, or failover, and stores only simple key-value items.
- Aurora Serverless v2
- A serverless Aurora configuration that scales capacity in fine-grained ACU increments as load changes, with a minimum of 0.5 ACU and no scale-to-zero. Version 1 could pause to zero capacity when idle.
- AWS Database Migration Service
- A managed replication service that performs full loads and ongoing change data capture between homogeneous or heterogeneous sources and targets, reading changes from source transaction logs.
- AWS Schema Conversion Tool
- A desktop tool that converts database schema, views, and stored procedures between engines and produces an assessment report listing objects it cannot convert automatically and the manual effort required.
- Aurora Global Database
- Storage-level replication from a primary region to up to five secondary regions, typically with under one second of lag. Secondaries are read-only and can be promoted for disaster recovery in under a minute.
- RDS Multi-AZ deployment
- A synchronous standby instance in a different Availability Zone with automatic failover on failure. It provides high availability only; the standby does not serve read traffic.
- RDS Blue/Green Deployments
- A managed workflow that creates a staging copy of the production environment, replicates changes, then switches traffic over by DNS swap, enabling major engine upgrades with minimal downtime and fast rollback.
- Babelfish for Aurora PostgreSQL
- A capability that lets Aurora PostgreSQL understand T-SQL and the SQL Server wire protocol, reducing code change when migrating SQL Server applications to Aurora.
- RDS automated backup retention
- Automated backups support a retention period from 0 to 35 days and enable point-in-time recovery to any second in that window. Setting retention to 0 disables both backups and recovery.
- RDS Proxy
- A managed connection pooler that multiplexes client connections, prevents Lambda connection exhaustion, supports IAM authentication, and shortens failover by preserving client connections.
- Aurora Backtrack
- A feature that rewinds an Aurora MySQL cluster in place to an earlier point in time without restoring a snapshot. The maximum configurable backtrack window is 72 hours.
- DynamoDB TTL
- A per-table timestamp attribute that makes DynamoDB delete expired items at no write capacity cost. Items are typically removed within 48 hours after their expiry time.
- DynamoDB point-in-time recovery
- Continuous backup of a table with a fixed 35-day window, allowing restore to any second within that window. Restores always create a new table, not an overwrite of the existing one.
- Aurora storage auto-growth
- Aurora storage expands automatically in 10 GiB increments up to a maximum of 128 TiB. Storage is never provisioned, and you pay only for the space actually consumed.
- Aurora custom endpoint
- A cluster endpoint that routes to a chosen subset of Aurora instances, letting you direct specific workloads such as reporting or analytics to designated instance classes.
- Performance Insights
- A database performance view that graphs database load as average active sessions segmented by wait event, helping identify the top SQL and bottlenecks. Free retention is 7 days, extendable to 731 days.
- Enhanced Monitoring
- An RDS and Aurora feature using a host agent to collect OS-level metrics such as memory, swap, and file system usage at granularities down to one second, delivered to CloudWatch Logs.
- Aurora ReplicaLag metric
- A CloudWatch metric reported in milliseconds measuring how far a read replica trails the writer. Sustained values above roughly 100 ms suggest the replica cannot keep pace.
- DynamoDB Contributor Insights
- A DynamoDB diagnostic that identifies the most frequently accessed and most throttled partition keys in a table, exposing hot-key patterns that cause request throttling.
- CloudWatch DatabaseConnections
- An RDS and Aurora metric counting current client connections. A steadily rising value usually indicates connection leaks or missing connection pooling in the application tier.
- RDS event subscriptions
- A mechanism that publishes RDS and Aurora events such as failover, low storage, backup failure, and maintenance windows to an SNS topic for alerting without API polling.
- IAM database authentication
- An RDS and Aurora feature that replaces stored passwords with a short-lived authentication token valid for 15 minutes, generated from IAM credentials and used over an encrypted connection.
- Encrypting an existing RDS instance
- Encryption cannot be enabled in place. Take a snapshot, copy the snapshot with encryption enabled using a KMS key, then restore a new instance from the encrypted snapshot.
- Secrets Manager credential rotation
- A managed service that stores RDS and Aurora credentials and rotates them automatically on a schedule using a Lambda rotation function, so applications never hold static passwords.
- DynamoDB LeadingKeys condition
- An IAM condition key that restricts which partition key values a principal may read or write, enabling per-tenant or per-user row-level isolation inside a shared DynamoDB table.
- DynamoDB encryption at rest
- DynamoDB encrypts all data at rest by default using an AWS owned key, an AWS managed key, or a customer managed KMS key chosen when the table is created.
- VPC gateway endpoint
- A VPC endpoint for DynamoDB and S3 that routes traffic over the AWS private network, avoiding NAT gateways and internet gateways while keeping database traffic private.