--- title: "Elasticsearch: Full-Text Search Engine Fundamentals" description: "Test your knowledge on full-text search, document indexing, and log analysis using Elasticsearch and Kibana." author: "Mohammad Abu Mattar" canonical: https://mkabumattar.com/quizzes/post/elasticsearch-search-engine-fundamentals-quiz --- # Elasticsearch: Full-Text Search Engine Fundamentals Welcome to the Elasticsearch Basics Quiz! Elasticsearch sits behind a large share of log analysis and real-time search. Whether you are troubleshooting a production crash by digging through Filebeat logs or building a performance dashboard in Kibana, understanding the underlying index structure and the Query DSL is an important skill for DevOps engineers. Let's see how much you know! ## Questions ### 1. What is the primary purpose of Elasticsearch? - To act as a primary relational storage for ACID transactions - To provide distributed search and near real-time analytics - To provide a low-latency content delivery network for media assets - To function as a centralized firewall and network traffic controller **Hint:** Think about speed and search. ### 2. In Elasticsearch, what is an "Index" equivalent to in a SQL database? - A Row - A Table - A Database - A Column **Hint:** A container for similar data. ### 3. What format does Elasticsearch use to store documents? - XML - JSON - Protobuf - YAML **Hint:** Standard web object notation. ### 4. What is a "Shard" in Elasticsearch? - A specialized cache for frequently accessed search results - A horizontal partition of data that allows an index to scale - A backup copy of the cluster state stored in a remote repository - A hardware-level optimization for SSD-based indexing performance **Hint:** Breaking an index into pieces. ### 5. What is the "Query DSL"? - A binary protocol for high-speed data ingestion - A JSON-based language used to define searches and filters - A SQL-to-REST translation layer for external database drivers - A schema definition tool for enforcing strict data types **Hint:** Domain Specific Language. ### 6. Which HTTP method is used to retrieve a document by its ID? - POST - GET - HEAD - PUT **Hint:** Standard REST method. ### 7. What is the role of "Kibana" in the ELK stack? - To act as a persistent queue for incoming log streams - To provide a visual interface for data exploration and analysis - To parse and normalize raw text into structured JSON format - To manage the distribution of shards across physical nodes **Hint:** The window into the data. ### 8. What is a "Replica Shard"? - A temporary shard created during an index migration - A copy of a primary shard used for failover and read scaling - A shard that stores only metadata about the cluster state - A read-only shard used for long-term archival of old data **Hint:** A copy for safety. ### 9. Which port does Elasticsearch typically use for its REST API? - 9300 - 9200 - 5601 - 9100 **Hint:** Between 9000 and 9500. ### 10. What is an "Inverted Index"? - A data structure that sorts documents by their creation date - A mapping of unique terms to the documents they appear in - A backup index created in reverse order for disaster recovery - A method for compressing text fields to reduce disk usage **Hint:** How Elasticsearch searches so fast. ### 11. Which Elasticsearch field type is used for "Full-Text Search"? - keyword - text - binary - flattened **Hint:** Analyzed strings. ### 12. What is the purpose of "Mapping" in Elasticsearch? - To visualize geographical coordinates on a Kibana map - To define the schema and data types of document fields - To distribute documents across specific physical disk drives - To track the relationships between different indexes **Hint:** Defining the schema. ### 13. What is a "Node" in an Elasticsearch cluster? - A specific JavaScript function within the Query DSL - A single running instance of Elasticsearch in a cluster - An individual entry in an inverted index term list - A hardware load balancer that distributes API requests **Hint:** A single instance. ### 14. In Kibana, what is the "Discover" tab used for? - To browse the Kibana marketplace for new dashboard themes - To interactively explore, filter, and view raw document data - To perform automated security scans on the Elasticsearch cluster - To detect and automatically fix broken index mappings **Hint:** Raw data exploration. ### 15. What does the "Match" query do in Elasticsearch? - Finds documents that have identical field values - Analyzes a search string and performs a full-text query - Identifies and merges duplicate documents in an index - Compares two different indexes for structural differences **Hint:** The standard search. ### 16. What is "Score" (_score) in search results? - The percentage of disk space occupied by the index - A numeric value indicating document relevance to a query - The number of times a document has been viewed by users - A performance metric showing the query execution time **Hint:** Relevance calculation. ### 17. What is the purpose of an "Alias" in Elasticsearch? - To provide an encrypted nickname for sensitive API keys - To provide a secondary name for one or more indexes - To compress the name of an index to save memory - To create a hard link to a remote cluster index **Hint:** A secondary name for an index. ### 18. What is "Logstash" used for? - To act as a high-speed load balancer for Kibana - To ingest, transform, and ship data to Elasticsearch - To store long-term archival data in a compressed format - To provide a command-line interface for the REST API **Hint:** The "L" in ELK. ### 19. What is an "Aggregations" query (aggs)? - A specialized query for retrieving large binary objects - A way to summarize and group data for analytics - A method for merging multiple documents into a single entry - A process for moving shards between different nodes **Hint:** Analytics and grouping. ### 20. What is a "Mapping Conflict"? - When two indices have the same name in different clusters - When a field is indexed with incompatible data types - When the master node fails to sync with data nodes - When two users attempt to update a document simultaneously **Hint:** Type mismatch. ### 21. Which tool focuses on lightweight data shipping in the Elastic Stack? - Logstash Data-Pump - Beats (Filebeat, Metricbeat) - Kibana Lens - Elastic Search-Agent **Hint:** Small, purpose-built agents. ### 22. What is the "Bulk API"? - An API for retrieving documents in large batches - An API for performing many index/delete operations at once - A management tool for upgrading the cluster version - A specialized query for searching through encrypted data **Hint:** High-speed ingestion. ### 23. What does "Near Real-Time" (NRT) mean in Elasticsearch? - Data is searchable exactly 1 hour after indexing - There is a slight delay before indexed data is searchable - Data is written to memory but only searchable after a restart - Queries only return results that were indexed yesterday **Hint:** Indexing latency. ### 24. What is the purpose of the "Term" query? - To find documents containing a specific analyzed sentence - To find documents that contain an exact, unanalyzed value - To calculate the frequency of words across an entire index - To define the expiration time of a specific document **Hint:** Exact matching. ### 25. What is "Lucene"? - A visualization plugin for displaying network graphs - The search library that Elasticsearch is built upon - A cloud-based orchestration tool for Elastic clusters - A specialized data type for storing 3D model geometry **Hint:** The engine under the hood. ### 26. In Kibana, what is an "Index Pattern"? - A graphical template for designing index mappings - A setting that tells Kibana which indices to visualize - A mathematical formula used for relevance scoring - A security rule that restricts access to specific documents **Hint:** How Kibana knows where to look. ### 27. What is "Split Brain" in a cluster? - A performance optimization that splits queries across CPUs - A state where two nodes both believe they are the Master - A backup strategy where data is mirrored to a separate cluster - An indexing method that separates text and numeric data **Hint:** A failure in consensus. ### 28. What is "Canvas" in Kibana? - A low-level API for drawing custom charts in JavaScript - A data-driven presentation tool for infographic dashboards - A background service that cleans up deleted shards - A sandbox environment for testing new index mappings **Hint:** Advanced presentation. ### 29. Which command shows the health of an Elasticsearch cluster? - GET /_cluster/stats - GET /_cluster/health - GET /_node/status - GET /_system/health **Hint:** API for health. ### 30. What is "Index Lifecycle Management" (ILM)? - A security protocol for rotating database passwords - A way to automate the movement and deletion of indices - A tool for recovering deleted documents from the trash bin - A method for calculating the uptime of a cluster node **Hint:** Automating index aging.