AWS Database Services and Concepts Flashcards

Flashcards testing concepts, features, operations, and capacity calculations across AWS database services based on the lecture transcript.

Which AWS service is appropriate for a fully managed relational database supporting SQL, ACID transactions, and traditional applications?

Amazon RDS

Which high-performance relational database service is compatible with MySQL or PostgreSQL and offers automated storage growth, replication, and high availability?

Aurora

Which ACID property guarantees that a transaction is treated as an indivisible unit?

Atomicity

Which ACID property ensures that transactions leave the database in a valid state according to defined rules?

Consistency

Which ACID property prevents concurrent transactions from interfering with each other?

Isolation

Which ACID property ensures that committed data survives failures?

Durability

Which RDS feature allows read-heavy workloads to be separated from the primary database?

Read Replicas

What is Aurora Backtrack primarily used for?

Rewinding a database to an earlier point in time

Which endpoint should an application use to route read traffic to Aurora read replicas without manually specifying individual instances?

Reader endpoint

What mechanism is used to control concurrent access when two transactions attempt to modify the same database resource simultaneously?

LOCK

What is the simplest primary key configuration in Amazon DynamoDB?

Partition key only

In a DynamoDB table with both a partition key and a sort key, what requirement must be met for item uniqueness?

The combination of the partition key and sort key must be unique

Why is an attribute like movie_language generally considered a poor partition key for a large DynamoDB table?

It has few distinct values and can create an uneven data distribution (hot partition)

What does a Local Secondary Index (LSI) provide in DynamoDB?

An alternative sort key using the same partition key as the base table

When must a Local Secondary Index (LSI) be created for a DynamoDB table?

At table creation time

What is the maximum number of Local Secondary Indexes (LSIs) allowed per DynamoDB table?

$$5$$

From where do Local Secondary Indexes (LSIs) consume read and write capacity units?

LSIs use the main table's provisioned WCUs and RCUs

What does a Global Secondary Index (GSI) provide in DynamoDB?

An alternative primary key (different partition key and optional sort key)

When can a Global Secondary Index (GSI) be added to a DynamoDB table?

After table creation (at any time)

What can happen to the main DynamoDB table if write operations on a GSI become throttled?

The main table can also be throttled

Which DynamoDB API call creates a new item or completely replaces an existing item with the same primary key?

PutItem

Which DynamoDB API call modifies attributes of an existing item or creates the item if it does not exist?

UpdateItem

Which DynamoDB operation efficiently retrieves multiple items based on a partition key and optional sort key conditions?

Query

Which DynamoDB operation inspects every item in the entire table?

Scan

What DynamoDB feature prevents concurrent updates from overwriting data incorrectly by verifying criteria before performing a write?

Conditional Write

What is PartiQL for DynamoDB?

A SQL-compatible query language for performing DynamoDB operations

What is the default consistency model for reads in Amazon DynamoDB?

Eventually consistent

How do you request a strongly consistent read in supported DynamoDB API operations?

Set ConsistentRead to True

How does RCU consumption compare between a strongly consistent read and an eventually consistent read?

A strongly consistent read consumes twice the RCUs of an eventually consistent read

What is the capacity unit rule for 1WCU in DynamoDB?

$$1\,\text{WCU} = 1\,\text{write per second for an item up to } 1\,\text{KB}$$

What is the capacity unit rule for 1RCU in DynamoDB for the DEA-C01 exam?

$$1\,\text{RCU} = 1\,\text{strongly consistent read/sec OR } 2\,\text{eventually consistent reads/sec for an item up to } 4\,\text{KB}$$

How many WCUs are required to write $10$ items per second where each item size is $2\,\text{KB}$?

$$20\,\text{WCUs}$$

How many WCUs are required to write $6$ items per second where each item size is $4.5\,\text{KB}$?

$$30\,\text{WCUs}$$

How many WCUs are required to write $120$ items per minute where each item size is $2\,\text{KB}$?

$$4\,\text{WCUs}$$

How many RCUs are required for $10$ strongly consistent reads per second on $4\,\text{KB}$ items?

$$10\,\text{RCUs}$$

How many RCUs are required for $16$ eventually consistent reads per second on $12\,\text{KB}$ items?

$$24\,\text{RCUs}$$

How many RCUs are required for $10$ strongly consistent reads per second on $6\,\text{KB}$ items?

$$20\,\text{RCUs}$$

How many RCUs are required for $20$ eventually consistent reads per second on $8\,\text{KB}$ items?

$$20\,\text{RCUs}$$

How many RCUs are required for $12$ strongly consistent reads per second on $5\,\text{KB}$ items?

$$24\,\text{RCUs}$$

What application mitigation technique handles DynamoDB ProvisionedThroughputExceededException errors?

Exponential backoff

Which fully managed service provides microsecond, in-memory caching for DynamoDB read-heavy workloads?

DynamoDB Accelerator (DAX)

Which feature provides a time-ordered sequence of item-level modifications in a DynamoDB table?

DynamoDB Streams

Which feature automatically deletes items from a DynamoDB table after a specified expiration timestamp?

Time to Live (TTL)

Which DynamoDB capacity mode is recommended when application workloads are unpredictable and capacity planning is difficult?

On-demand

What type of workload is Amazon Redshift primarily designed to process?

Online Analytical Processing (OLAP)

What fundamental architecture gives Amazon Redshift its analytical performance capabilities?

Massively parallel processing (MPP) with columnar storage

Which Redshift distribution style distributes table rows across slices in a round-robin fashion?

EVEN

Which Redshift distribution style places rows across node slices based on values in a specified column?

KEY

Which Redshift distribution style replicates a copy of the entire table to every node?

ALL

Which distribution style allows Redshift to automatically choose the best data distribution method?

AUTO

What is the function of a sort key in Amazon Redshift?

It organizes data on disk according to specified column values to improve query scanning efficiency

Which Redshift command reclaims disk space from deleted rows and restores sort order?

VACUUM

Which option of the Redshift VACUUM command reclaims space from deleted rows without performing table sorting?

VACUUM DELETE ONLY

Which command is optimized for high-speed loading of large datasets from external sources into Redshift?

COPY

What external sources can the Redshift COPY command load data from?

S3, EMR, DynamoDB, and remote hosts

What two elements are required when running a COPY command from Amazon S3 into Amazon Redshift?

Manifest file and IAM role

Which command is used to export query results or data from Redshift to files in Amazon S3?

UNLOAD

Which Redshift feature allows direct querying of external Parquet files in S3 without loading them into Redshift storage?

Redshift Spectrum

Which feature enables Redshift queries to directly access live data in RDS/Aurora PostgreSQL and MySQL without an ETL process?

Redshift Federated Query

Can you query Redshift tables from RDS or Aurora using Redshift Federated Query?

No

Which feature automatically provides extra cluster capacity to handle spikes in concurrent read queries in Redshift?

Concurrency Scaling

What mechanism routes and manages queries sent to Redshift concurrency scaling clusters?

WLM queues

What is the purpose of Short Query Acceleration (SQA) in Amazon Redshift?

To prioritize short-running queries over long-running queries so they execute in a dedicated space without waiting in queues

What underlying technology does Redshift Short Query Acceleration (SQA) use to predict execution times?

Machine learning

Which feature allows executing SQL statements against Redshift over a secure HTTP endpoint without maintaining database connection pools?

Redshift Data API

Is the execution model of the Redshift Data API synchronous or asynchronous?

Asynchronous

How does the Redshift Data API handle authentication without sending raw passwords in API requests?

It uses AWS Secrets Manager or temporary credentials

Which AWS orchestration service can invoke Redshift Data API calls as part of an automated workflow?

Step Functions

Which Redshift deployment mode automatically provisions and scales resources based on demand without managing clusters?

Redshift Serverless

Which Redshift node architecture features independent scaling of compute and managed storage?

RA3

Which resizing method in Redshift quickly adds or removes nodes of the same node type?

Elastic resize

Which feature allows live data to be shared across Redshift clusters without performing data copies?

Cross-Region Data Sharing

Which Redshift system view category contains real-time transient data?

System Table Views

Which Redshift system view category contains historical performance data generated from logs persisted to disk?

System Table Logs

Where should large binary objects (BLOBs) generally be stored according to AWS best practices?

Amazon S3

Which AWS graph database supports Gremlin, openCypher, and SPARQL query languages?

Amazon Neptune

Which fully managed AWS database service is compatible with MongoDB?

Amazon DocumentDB

Which fully managed AWS database service is compatible with Apache Cassandra?

Amazon Keyspaces

Which Redis-compatible database service provides sub-millisecond latency along with multi-AZ durability?

Amazon MemoryDB

Which purpose-built AWS database is optimized for storing and analyzing time-series and IoT telemetry data?

Amazon Timestream

1 WCU =

1 write/sec for an item up to 1 KB

1 RCU represents how many STRONGLY CONSISTENT READ per second

1

1 RCU represents how many EVENTUALLY CONSISTENT READ per second

2

RCUs represents 1 strongly consistent read and 2 eventually consistent reads per second for how many KB in size

4 KB