DEA-C01 Data Ingestion and Transformation Practice Test 39 — 15 Questions

Question 1

A company uses AWS Database Migration Service (DMS) to migrate an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration is ongoing and uses change data capture (CDC). The engineer notices that the target database is falling behind the source by several hours. What is the MOST likely cause?

Accepted Answer

A large full load is being transferred, which delays the start of CDC.. Option B is correct because a large full load can delay the start of CDC, causing the target to fall behind. Option A is incorrect because increasing the replication instance size typically improves performance. Option C is wrong because CDC requires an active transaction log; disabling it would stop replication. Option D is wrong because parallel apply can actually speed up replication.

Answer

The target table has disabled parallel apply.

Answer

The replication instance is under-provisioned and needs to be larger.

Answer

Change data capture has been disabled on the source database.

Question 2

A company uses Amazon Kinesis Data Analytics for Apache Flink to process streaming data. The application reads from a Kinesis data stream and writes results to an Amazon S3 bucket. Recently, the application has been failing with 'ResourceNotFoundException' for the S3 bucket. What is the MOST likely cause?

Accepted Answer

The IAM role used by the application does not have s3:PutObject permission.. Option C is correct because Kinesis Data Analytics needs permissions to write to the S3 bucket; if the IAM role lacks s3:PutObject, the error occurs. Option A is wrong because the bucket name is used, not ARN. Option B is wrong because S3 bucket policies do not require versioning. Option D is wrong because Flink application code does not configure S3 bucket region; it's determined by the bucket location.

Answer

The S3 bucket ARN is incorrectly specified in the application configuration.

Answer

The Flink application code specifies the wrong AWS Region for the S3 bucket.

Answer

The S3 bucket has versioning disabled.

Question 3

A data engineer is designing a data ingestion pipeline for real-time clickstream data from a website. The data must be stored in Amazon S3 in near-real time, and also be available for real-time analytics using Amazon Athena. The pipeline must handle occasional spikes of up to 10x the normal throughput. Which combination of services should the engineer use?

Accepted Answer

Amazon Kinesis Data Streams with AWS Lambda to write to Amazon S3, and Amazon Athena for queries.. Option A is correct because Kinesis Data Streams can handle high throughput spikes, Lambda can process and write to S3, and Athena can query directly. Option B is wrong because SQS is pull-based and does not support push to S3 directly; Lambda would need to poll, adding latency. Option C is wrong because DMS is for database migration, not real-time clickstream. Option D is wrong because Glue is batch-oriented and not suitable for low-latency streaming.

Answer

Amazon Simple Queue Service (SQS) with AWS Lambda to write to Amazon S3, and Amazon Athena for queries.

Answer

AWS Database Migration Service (DMS) to stream data to Amazon S3, and Amazon Athena for queries.

Answer

Amazon Kinesis Data Firehose with AWS Glue for transformation, and Amazon Athena for queries.

Question 4

A company uses AWS Glue to run ETL jobs that process data from Amazon RDS to Amazon S3. The job runs successfully but the data in S3 is missing some records that exist in the source. The engineer notices that the job uses a JDBC connection and the query extracts data based on a timestamp column. What is the MOST likely cause of the missing records?

Accepted Answer

The timestamp column includes time portion and the job is using an exclusive upper bound.. Option B is correct because if the timestamp column includes time, records with the same timestamp may be missed if the job uses an exclusive upper bound. Option A is wrong because the job can read from different tables. Option C is wrong because the S3 bucket permissions would cause failure, not missing records. Option D is wrong because connection pooling does not cause missing records.

Answer

The S3 bucket lacks write permissions.

Answer

The JDBC connection uses connection pooling, causing some records to be dropped.

Answer

The Glue job is configured to only read from one table.

Question 5

A data engineer is ingesting data from an on-premises database to Amazon S3 using AWS DataSync. The data transfer is scheduled to run daily at midnight. The engineer notices that the transfer takes longer than expected and sometimes does not complete before the next scheduled task. What should the engineer do to ensure the transfer completes within the window?

Accepted Answer

Increase the bandwidth limit in the DataSync task settings.. Option C is correct because increasing the bandwidth limit allows DataSync to use more network capacity, speeding up the transfer. Option A is wrong because reducing the schedule frequency does not solve the completion time issue. Option B is wrong because changing to S3 Transfer Acceleration adds cost but may not help if the bottleneck is on-premises bandwidth. Option D is wrong because decreasing the limit would make it slower.

Answer

Decrease the bandwidth limit to reduce network congestion.

Answer

Increase the schedule frequency to every 12 hours.

Answer

Use S3 Transfer Acceleration instead of DataSync.

Question 6

A company uses Amazon Kinesis Data Firehose to deliver log data to Amazon S3. The data is transformed by a Lambda function that adds a timestamp field. Recently, the Firehose delivery stream has been failing with 'Lambda invocation failed' errors. The Lambda function's CloudWatch Logs show that the function is timing out. What is the MOST likely cause?

Accepted Answer

The Firehose buffer size is too large, causing the Lambda function to receive too many records.. Option D is correct because Firehose sends batches of records to Lambda; if the batch size is too large, the function may exceed its timeout. Option A is wrong because the Lambda function is being invoked, so permissions are fine. Option B is wrong because the error is about Lambda invocation, not memory. Option C is wrong because a 1-minute timeout is typical and may be insufficient for large batches.

Answer

The Lambda function lacks permission to write to CloudWatch Logs.

Answer

The Lambda function timeout is set to 1 minute, which is adequate.

Answer

The Lambda function is running out of memory.

Question 7

A data engineer needs to transform JSON data from Amazon S3 into Parquet format using AWS Glue. The data contains nested fields. Which Glue feature should the engineer use to define the schema and handle the nested structure?

Accepted Answer

Use the 'Relationalize' transform in a Glue ETL script.. Option A is correct because Glue's built-in transform 'Relationalize' converts nested JSON into flat tables. Option B is wrong because 'FindMatches' is for deduplication. Option C is wrong because 'Spigot' is for sampling. Option D is wrong because 'DropFields' is for removing fields, not handling nesting.

Answer

Use the 'FindMatches' transform to identify duplicates.

Answer

Use the 'DropFields' transform to remove nested fields.

Answer

Use the 'Spigot' transform to write sample data.

Question 8

A company uses AWS Glue to process data from Amazon S3. The Glue job fails with a 'SchemaDetectionException'. The data engineer wants to ensure the schema is correctly inferred. Which TWO actions should the engineer take? (Choose two.)

Accepted Answer

Use the Glue Data Catalog as the source for schema definition.. Options A and D are correct. Option A ensures the job reads all files for schema inference. Option D uses the Glue Data Catalog to store a consistent schema. Option B is wrong because adding a separate column does not help schema detection. Option C is wrong because converting to Parquet may change the schema but does not guarantee correct inference. Option E is wrong because increasing parallelism does not affect schema detection.

Answer

Add a column with a default value to the data.

Answer

Increase the number of Glue DPUs to speed up processing.

Answer

Convert all input files to Parquet format.

Question 9

A data engineer is designing a data ingestion pipeline that uses AWS DMS to migrate data from an on-premises Oracle database to Amazon S3 in Parquet format. The engineer needs to ensure that data is continuously replicated with minimal latency. Which THREE steps should the engineer take? (Choose three.)

Accepted Answer

Configure a DMS task with a transformation rule to convert to Parquet.. Options A, C, and E are correct. Option A enables continuous replication using CDC. Option C uses a transformation to convert to Parquet. Option E uses a target endpoint for S3 with parquet format. Option B is wrong because SCT is for schema conversion, not for DMS replication. Option D is wrong because a full load only is not continuous replication.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema.

Answer

Perform a full load only, without CDC.

Question 10

A company uses Amazon Kinesis Data Streams to ingest clickstream data. The data must be transformed and stored in Amazon S3 for batch analytics. The engineer wants to use AWS Lambda for transformation. Which TWO configurations are required? (Choose two.)

Accepted Answer

Create an event source mapping from the Kinesis stream to the Lambda function.. Options A and D are correct. Option A: Lambda needs an event source mapping to poll from Kinesis. Option D: Lambda needs an IAM role with permissions to read from Kinesis and write to S3. Option B is wrong because Lambda does not write directly to S3 via Kinesis; it writes via the Lambda function. Option C is wrong because Lambda does not use SQS to trigger from Kinesis. Option E is wrong because Lambda does not write to S3 via Firehose; Firehose can directly write to S3.

Answer

Configure the Lambda function to write to S3 via Kinesis Data Firehose.

Answer

Configure the Kinesis stream to send records directly to S3.

Answer

Set up an SQS queue as a destination for Lambda errors.

Question 11

A data engineer is building a real-time data pipeline to ingest sensor data from IoT devices. The data is sent to AWS IoT Core, which publishes messages to a Kinesis Data Stream. Each message is about 1 KB in size. The data must be transformed (add a device location field) and then stored in Amazon S3 for long-term analytics. The engineer has set up a Lambda function to transform the records and write to S3. However, the engineer notices that the Lambda function is invoked thousands of times per second, causing high costs and occasional throttling. The Lambda function processes only one record at a time. The engineer wants to reduce the number of Lambda invocations and improve throughput. What should the engineer do?

Accepted Answer

Configure the event source mapping to use a larger batch size and set a batch window.. Option C is correct because increasing the batch size in the event source mapping allows Lambda to process multiple records per invocation, reducing invocations. Option A is wrong because increasing Lambda memory does not reduce invocations. Option B is wrong because Firehose can batch records, but the transformation would still be per record unless using Firehose's built-in Lambda integration. Option D is wrong because reducing concurrent executions would cause throttling and backlogs.

Answer

Reduce the number of shards in the Kinesis stream to limit concurrency.

Answer

Increase the Lambda function's memory allocation to improve performance.

Answer

Replace the Lambda function with Amazon Kinesis Data Firehose and use its built-in transformation.

Question 12

A company runs a nightly batch ETL job using AWS Glue to transform data from Amazon RDS for MySQL to Amazon S3. The job reads 100 tables and writes Parquet files partitioned by date. Recently, the job started failing with 'ThrottlingException' from the RDS database. The data volume has increased, and the Glue job is reading large tables without any filtering. The job uses a single Glue job with multiple Spark executors. The engineer needs to reduce the load on the RDS database while maintaining the same processing time. What should the engineer do?

Accepted Answer

Modify the Glue job to use a JDBC connection with a WHERE clause to read only the latest partition.. Option D is correct because using a JDBC connection with a WHERE clause to filter data by date reduces the amount of data read from RDS, reducing throttling. Option A is wrong because increasing DPUs would increase parallelism and potentially increase load on RDS. Option B is wrong because DMS is a migration tool, not for regular ETL. Option C is wrong because reading all data into S3 first does not reduce load on RDS; the initial read still causes throttling.

Answer

Use AWS DMS to continuously replicate data to S3 and then run Glue on the S3 data.

Answer

Change the job to read all data from RDS into a staging table in S3 first, then transform.

Answer

Increase the number of DPUs to process data faster.

Question 13

A data engineer is setting up a data ingestion pipeline using Amazon Kinesis Data Firehose to deliver web server logs to Amazon S3. The logs are in JSON format and the engineer wants to convert them to Parquet format. The engineer has configured a Glue table for the schema. However, when testing, the Firehose delivery stream fails with 'Error converting to Parquet'. The engineer checks the Glue table schema and notices that it includes a column 'timestamp' of type 'string' in the format 'yyyy-MM-dd HH:mm:ss'. The logs have a 'timestamp' field in the same format. What is the MOST likely cause of the failure?

Accepted Answer

The Glue table schema does not match the data schema exactly.. Option A is correct because Firehose requires the schema to match the data exactly. If the Glue table schema is not consistent with the data, conversion fails. Option B is wrong because Firehose supports Parquet conversion with Glue schema. Option C is wrong because S3 bucket permissions would cause a different error. Option D is wrong because string type is acceptable for conversion.

Answer

Firehose does not support Parquet conversion.

Answer

The S3 bucket lacks write permissions for Firehose.

Answer

The 'timestamp' column must be of type 'timestamp' instead of 'string'.

Question 14

A company is ingesting streaming data from IoT devices into Amazon Kinesis Data Streams. The data is then processed by an AWS Lambda function that transforms the records and writes them to an Amazon S3 bucket. Recently, the Lambda function has been timing out and the S3 bucket is not receiving all expected data. The Kinesis stream is not throttling and has sufficient shards. Which step should the company take to resolve this issue?

Accepted Answer

Increase the Lambda function's timeout and memory allocation.. Option B is correct because increasing the Lambda function's timeout and memory allows it to handle larger or more frequent records within the execution duration. Option A is wrong because Kinesis is not the bottleneck. Option C is wrong because increasing shards does not address Lambda timeouts. Option D is wrong because there is no mention of Lambda hitting concurrency limits.

Answer

Increase the Lambda function's reserved concurrency.

Answer

Increase the number of shards in the Kinesis stream.

Answer

Enable enhanced fan-out on the Kinesis stream to reduce latency.

Question 15

A data engineer needs to ingest data from an on-premises Oracle database into Amazon S3 for analytics. The data changes frequently and the engineer wants to capture both initial load and incremental changes with minimal latency. Which TWO AWS services should be used together? (Choose TWO.)

Accepted Answer

AWS Database Migration Service (DMS). Option B and Option D are correct. AWS DMS can continuously replicate changes from Oracle to S3, and Amazon Kinesis Data Streams can provide low-latency streaming for near-real-time data. Option A is for batch file transfer, not real-time. Option C is for ETL, not replication. Option E is for event-driven processing but not direct database replication.

Answer

AWS Lambda

Answer

AWS Glue

Answer

AWS Transfer Family