Search performance tuning in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of using filters instead of queries in Elasticsearch for search performance?

Filters are faster because they cache results and do not calculate relevance scores, making repeated searches quicker.

intermediate

How does the _source field affect search performance in Elasticsearch?

Disabling or limiting the _source field reduces the amount of data retrieved, improving search speed and reducing network load.

intermediate

What is the benefit of using doc_values for fields in Elasticsearch?

doc_values store field values on disk in a columnar format, making sorting and aggregations faster and more memory efficient.

advanced

Why should you avoid using scripted fields in search queries for performance tuning?

Scripted fields run custom code at query time, which is slower and uses more CPU, so avoiding them improves search speed.

intermediate

How does setting index.refresh_interval affect search performance?

Increasing index.refresh_interval reduces how often Elasticsearch refreshes the index, improving indexing speed but delaying search visibility of new data.

Which Elasticsearch feature caches filter results to speed up repeated searches?

A Aggregations

B Filters

C Scripted fields

D Queries

Filters cache their results, making repeated searches faster by avoiding recalculations.

What does disabling the _source field do?

A Improves search speed by reducing data retrieval

B Increases relevance scoring

C Enables scripted fields

D Improves indexing speed only

Disabling _source reduces the data sent back, improving search speed.

Why are doc_values important for sorting and aggregations?

A They increase indexing speed

B They cache query results

C They disable scoring

D They store data in a columnar format on disk

doc_values store field data efficiently for fast sorting and aggregation.

What is a downside of using scripted fields in queries?

A They slow down queries due to runtime code execution

B They disable caching

C They reduce index size

D They improve search speed

Scripted fields run code during queries, which uses more CPU and slows performance.

Increasing index.refresh_interval will:

A Disable caching

B Make searches faster immediately

C Improve indexing speed but delay new data visibility in searches

D Reduce index size

A longer refresh interval means fewer refreshes, speeding indexing but delaying search updates.

Explain how caching filters improves Elasticsearch search performance.

Think about how remembering answers helps you answer faster next time.

Describe the trade-off involved when increasing the index.refresh_interval setting.

Consider how often you update a notice board affects how fresh the info is.