Services for collecting, processing, querying, and visualizing data at scale — from streaming ingestion to data warehousing and BI dashboards.

Amazon Athena

Serverless SQL queries run directly against data sitting in S3 — no servers, no loading, pay per byte scanned.

  • Point Athena at S3, define a table, run standard SQL — the data never moves and there is no ETL or load step
  • Serverless: nothing to provision, nothing running and nothing billed between queries
  • Table and schema metadata lives in the AWS Glue Data Catalog; Glue crawlers can infer it for you
  • You are billed for bytes scanned, so partitioning, compression, and columnar formats (Parquet/ORC) are the cost lever — not query tuning

Exam triggers

Phrases and scenarios that point here.

  • "Query data in S3", "ad hoc", "standard SQL", "no infrastructure to manage" → Athena
  • Analyze logs already sitting in S3 (CloudTrail, VPC Flow Logs, ALB, CUR) → Athena
  • "Least operational overhead" + infrequent or occasional queries → Athena, not Redshift or EMR
  • "Reduce Athena cost" → scan less data: partition, compress, convert to Parquet

Not this service

  • Frequent, complex BI reporting on loaded structured data → Redshift
  • Custom Spark/Hadoop processing with cluster control → EMR
  • Building the catalog or transforming the data itself → AWS Glue (Athena queries it, Glue prepares it)

Use cases

  • Log forensics — "who deleted that bucket last Tuesday?" Point Athena at the CloudTrail bucket and answer it with a WHERE clause instead of a support ticket
  • Investigating a slow or suspicious network path in VPC Flow Logs, without standing up a logging stack for a question you'll ask twice a year
  • Billing archaeology — query the Cost and Usage Report in S3 to find which team actually owns a line item that jumped last month
  • One-off analyst questions against a data lake, where nobody wants to build a warehouse for a number marketing needs once
  • The SQL layer beneath a QuickSight dashboard, so BI users see raw S3 data without an ETL pipeline in front of it

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

Amazon EMR

Managed clusters for running open-source big data frameworks like Spark and Hadoop on AWS.

  • Runs the open-source big data stack — Spark, Hive, Presto/Trino, HBase, Flink — with AWS provisioning and configuring the EC2 fleet
  • Three node types: primary (coordinates), core (runs tasks and holds HDFS), task (compute only, optional)
  • Storage: HDFS lives on core nodes and dies with the cluster; EMRFS reads and writes S3 directly, so data outlives the cluster
  • Transient clusters run one job and self-terminate; long-running clusters stay up for interactive and ad hoc work
  • Four deployment flavors: EMR on EC2 (the default), EMR Serverless (no cluster), EMR on EKS, EMR on Outposts

Exam triggers

Phrases and scenarios that point here.

  • "Hadoop", "Spark", "Hive", "Presto", "HBase", "Flink" named in the question → EMR, almost always
  • Migrate an on-premises Hadoop or Spark cluster to AWS without rewriting the jobs
  • "Petabyte-scale", "massive log/clickstream processing", "big data analytics" with code that already exists
  • Team needs control over the framework and its version → EMR, not a fully abstracted service

Not this service

  • Serverless ETL with a built-in data catalog, nothing to size → AWS Glue
  • Ad hoc SQL straight against S3, nothing to run or manage → Amazon Athena
  • Data warehouse for BI dashboards and reporting → Amazon Redshift

Use cases

  • Lifting a decade of on-prem Spark and Hive jobs into AWS — same frameworks, someone else's hardware
  • Nightly data lake ETL: read raw CSV and JSON from S3, write partitioned Parquet back for Athena and Redshift to query
  • Transient cluster for a monthly billing run — spins up at 2am, chews through the month's usage records, terminates itself before anyone wakes up
  • Backfills and reprocessing: replaying two years of archived clickstream in an afternoon by throwing 200 Spot task nodes at it
  • A long-running cluster as a shared analytics sandbox, with EMR Studio notebooks for data scientists poking at the lake in PySpark

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

Amazon Kinesis Data Streams

Managed service for ingesting real-time streaming data and keeping it available for multiple consumers to read and re-read.

  • Reading doesn't delete — data stays for the full retention window, so many consumers can read the same stream independently
  • Shard = the throughput unit: 1 MB/s or 1,000 records/s in, 2 MB/s out; records land in order within a shard
  • Provisioned mode = you choose the shard count; On-demand mode = AWS scales shards for you
  • Limits: 1 MB max record size, 24-hour default retention (extendable to 365 days), partition key decides the shard

Exam triggers

Phrases and scenarios that point here.

  • "Real time", "streaming", "clickstream", "IoT telemetry", "within seconds"
  • Multiple teams or applications need the same events for different purposes → Data Streams, not SQS
  • Must be able to replay or reprocess data after a failure → Data Streams retention
  • Order matters per device/user/session → partition key keeps those records on one shard

Not this service

  • Just land the stream in S3, Redshift, or OpenSearch with no code → Amazon Data Firehose
  • One message, one consumer, then it's gone → SQS
  • Windowed aggregations or SQL over the stream → Amazon Managed Service for Apache Flink

Use cases

  • Clickstream on a retail site where one consumer drives a live traffic dashboard and another archives to S3 — same stream, two readers, neither blocking the other
  • Fleet telemetry from delivery bikes, using bike ID as the partition key so each bike's GPS pings stay in order even as the fleet grows
  • Real-time fraud scoring on payment events, where a scoring consumer reacts in seconds and a nightly batch job re-reads the same records for reporting
  • Log ingestion for an app too chatty for a single processor — fan out to a Lambda consumer for alerting and a Firehose consumer for the data lake
  • Recovering from a bad consumer deploy: because records are retained, you rewind and reprocess the last few hours instead of losing them

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

Amazon OpenSearch Service

Managed search and analytics engine for log analytics, full-text search, and operational dashboards.

  • A domain is a cluster — you pick instance types and node counts, AWS provisions, patches, and replaces failed nodes
  • Two flavors: managed clusters (you size the nodes) and Serverless collections (capacity scales for you in OCUs)
  • OpenSearch Dashboards is the built-in visualization UI — the successor to Kibana, included with every domain
  • Storage tiers step down in cost and speed: hot (EBS) → UltraWarm → cold (both S3-backed)
  • Reality check: this was Amazon Elasticsearch Service until 2021 — older question banks and blog posts still say "Elasticsearch"

Exam triggers

Phrases and scenarios that point here.

  • "Full-text search", "relevance ranking", "search across large volumes of text" → OpenSearch
  • "Centralized log analytics", "SIEM", "security analytics", "operational dashboards" → OpenSearch
  • The word "Kibana" or "Elasticsearch" appears anywhere → the AWS answer is OpenSearch Service
  • Streaming logs that must be searchable and visualized in near real time → Firehose or OpenSearch Ingestion into OpenSearch

Not this service

  • Simple log storage with occasional queries and metric alarms → CloudWatch Logs
  • Ad hoc SQL over files already sitting in S3 → Athena
  • Business dashboards and charts for non-technical users → Amazon Quick (the service formerly called QuickSight)

Use cases

  • Central log search across a whole fleet — app logs, VPC flow logs, and ALB logs in one index, so you trace a failed request without SSH-ing into a single box
  • Product search on a storefront — typo tolerance, faceted filters (brand, size, price), and relevance tuning that a SQL LIKE query will never give you
  • Security analytics — CloudTrail, WAF, and firewall logs indexed together so an analyst can follow one attacker's session across services
  • Live operations dashboards — error rate, p99 latency, and order counts on a wall screen refreshing every few seconds
  • Vector search for RAG chatbots — store embeddings next to your text and ask "find me things similar to this" instead of matching keywords

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

Amazon QuickSight

Serverless business intelligence service for building and sharing interactive dashboards.

  • Two user roles: Authors connect to data and build dashboards, Readers just view and filter them
  • SPICE = in-memory engine; import a snapshot for fast repeat queries, or Direct Query to hit the live source
  • Connects to S3, Athena, Redshift, RDS/Aurora, on-prem databases, SaaS apps, and uploaded CSV/Excel
  • Built-in ML with no ML skills: forecasting, anomaly detection, and plain-English Q&A via Amazon Q
  • Reality check: AWS renamed it "Amazon Quick Sight" under the Amazon Quick suite — exams and APIs still say QuickSight

Exam triggers

Phrases and scenarios that point here.

  • "Dashboard", "visualize", "business intelligence", "charts for business users" → QuickSight
  • Non-technical staff need to explore data without writing SQL → QuickSight
  • Embed interactive dashboards inside your own app or customer portal → QuickSight embedded analytics
  • Data already sits in S3 → Athena queries it, QuickSight draws it

Not this service

  • Running SQL against data in S3 → Athena (QuickSight sits on top of it)
  • CPU, latency, error-rate graphs for engineers → CloudWatch dashboards
  • Storing and warehousing the data itself → Redshift

Use cases

  • Weekly revenue dashboard on Redshift so leadership self-serves instead of asking an analyst for a fresh CSV every Monday
  • Customer-facing analytics embedded in a SaaS product — "your store's traffic this month" — without building a charting stack in-house
  • FinOps dashboards over Cost and Usage Report data in S3, so each engineering team sees its own spend without opening Cost Explorer
  • Retail chain with hundreds of store managers on cheap Reader seats, all hitting one nightly SPICE snapshot instead of hammering the production database
  • Anomaly alerts on business metrics — refund rate suddenly doubles — caught by built-in ML rather than someone eyeballing a report

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

Amazon Redshift

Fully managed, petabyte-scale data warehouse for SQL analytics and BI reporting on large datasets.

  • OLAP, not OLTP — built to scan and aggregate billions of rows, not to serve single-row app lookups
  • Columnar storage + MPP: a leader node plans the query, compute nodes run it in parallel on their own slice of data
  • Two flavours: Serverless (pay per RPU-second while active, no cluster to size) and Provisioned (node-hours, pause/resume, Reserved Instances)
  • Spectrum queries data sitting in S3 directly — no loading, join warehouse tables to lake files in one SQL statement
  • Reality check: AWS now steers new clusters to Graviton-based RG nodes with a built-in lake query engine; exam material still says RA3 and DC2

Exam triggers

Phrases and scenarios that point here.

  • "Data warehouse", "OLAP", "business intelligence", "petabyte-scale analytics", "complex joins across large tables"
  • Reporting queries are crushing the production database → move analytics to Redshift, leave RDS to the app
  • Analytics run only at month-end or business hours → Redshift Serverless, no capacity planning
  • Query existing S3 data from the warehouse without an ETL load → Redshift Spectrum

Not this service

  • Occasional ad hoc SQL over S3, nothing to run or manage → Athena
  • Transactional app database, single-row reads and writes → RDS or Aurora
  • Spark, Hadoop or custom processing instead of SQL → EMR
  • The dashboards and charts themselves → QuickSight (Redshift is what it queries)

Use cases

  • One reporting warehouse fed nightly from orders, CRM and billing, so finance runs a single query instead of reconciling three exports
  • Five years of clickstream in one place to answer questions no single app database can — which acquisition channel actually produces repeat buyers
  • BI backend for QuickSight, Tableau or Power BI, where a few hundred analysts hit the same tables every Monday morning
  • Hot months live in the warehouse, cold years stay in S3 as Parquet, and Spectrum joins both in one query — you keep the history without paying warehouse storage for it
  • Serverless for a warehouse that only wakes up for the month-end close, so the other 25 days cost nothing in compute

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09

AWS Glue

Serverless data integration service that discovers your data's schema, catalogs it, and runs ETL jobs without any servers to manage.

  • Two halves, tested separately: the Data Catalog (metadata — what your data is) and ETL jobs (serverless Spark that moves and transforms it)
  • Crawlers scan S3 and JDBC sources, infer schema and partitions, and write table definitions into the Data Catalog — the data itself never moves
  • Athena, Redshift Spectrum, and EMR all read the same Data Catalog — crawl once, query from anywhere
  • No-code paths exist: Glue Studio (visual ETL canvas) and DataBrew (point-and-click cleaning for analysts who don't write Spark)

Exam triggers

Phrases and scenarios that point here.

  • "Serverless ETL", "no infrastructure to manage", "prepare and transform data for analytics"
  • Files already sitting in S3 with no schema defined → Glue crawler + Data Catalog, then Athena
  • "Central metadata repository shared across analytics services" → Glue Data Catalog
  • Transform + load → Glue; query in place, no transform → Athena; long-running tuned cluster → EMR

Not this service

  • Run SQL over S3 without moving or reshaping anything → Athena
  • Persistent Hadoop/Spark cluster you tune, patch, and keep warm → EMR

Use cases

  • A partner drops CSVs into S3 every night — a scheduled crawler picks up the new partitions and the data is queryable in Athena by morning, with nobody hand-writing a schema
  • Converting sprawling raw CSV/JSON into partitioned Parquet, so every downstream Athena query scans a fraction of the bytes and costs a fraction as much
  • Nightly job joining a database export with clickstream files into one flat reporting table that QuickSight points at
  • One-off backfill over years of archived logs — the Spark capacity spins up, chews through it, and disappears, leaving no cluster to remember to shut down
  • An analyst dedupes rows, fixes date formats, and standardizes country codes in DataBrew instead of filing a ticket with the data team

Commonly confused with

Full notes →

Verified against AWS documentation · 2026-09-09