Index refresh interval in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the index refresh interval in Elasticsearch?

It is the time period Elasticsearch waits before making newly indexed data searchable. It controls how often the index is refreshed.

intermediate

How does changing the index refresh interval affect search results?

A shorter refresh interval means new data appears in search results faster but can use more resources. A longer interval delays new data visibility but reduces resource use.

beginner

What is the default index refresh interval in Elasticsearch?

The default refresh interval is 1 second, meaning Elasticsearch refreshes the index every second to make new data searchable.

intermediate

How can you change the index refresh interval for an existing Elasticsearch index?

You can update it using the update settings API with a command like: <br>PUT /my_index/_settings { "index" : { "refresh_interval" : "5s" } }

advanced

Why might you want to temporarily disable the index refresh interval?

Disabling refresh (setting interval to -1) during heavy data loading improves indexing speed because Elasticsearch skips refreshing until you enable it again.

What does the Elasticsearch index refresh interval control?

A How often data is deleted

B How often the cluster restarts

C How often backups are made

D How often new data becomes searchable

The refresh interval controls how often Elasticsearch refreshes the index to make new data searchable.

What is the default refresh interval in Elasticsearch?

A 10 seconds

B 1 second

C 5 minutes

D Disabled by default

By default, Elasticsearch refreshes the index every 1 second.

Setting the refresh interval to -1 means:

A Refresh is disabled

B Refresh happens every millisecond

C Refresh happens every minute

D Refresh interval is set to default

A refresh interval of -1 disables automatic refreshing.

Why might you increase the refresh interval during bulk indexing?

A To delete old data faster

B To make data searchable faster

C To reduce resource use and improve indexing speed

D To increase cluster size

Increasing the refresh interval reduces how often Elasticsearch refreshes, saving resources and speeding up bulk indexing.

How do you change the refresh interval for an index named 'logs' to 10 seconds?

A PUT /logs/_settings { "index": { "refresh_interval": "10s" } }

B GET /logs/_refresh?interval=10s

C POST /logs/_update { "refresh": 10 }

D DELETE /logs/_refresh_interval

You update the index settings with a PUT request specifying the new refresh_interval.

Explain what the index refresh interval is and how it affects Elasticsearch performance and search results.

Think about how often Elasticsearch updates its view of new data.

Describe how to change the index refresh interval for an existing index and why you might want to do this.

Consider bulk data loading scenarios.