Deleting an index in Elasticsearch is necessary when:
- You need to remove outdated or unnecessary data
- You're restructuring your data architecture
- You want to free up storage space
- You're cleaning up test or temporary indices
- You need to comply with data retention policies
Steps to delete an index
Verify the index exists:
GET /_cat/indices?v
Backup important data (optional but recommended):
POST /_reindex { "source": { "index": "index_to_delete" }, "dest": { "index": "backup_index" } }
Delete the index:
DELETE /index_to_delete
Verify the index has been deleted:
GET /_cat/indices?v
Additional Information and Best Practices
- Always double-check the index name before deletion to avoid accidental data loss
- Use index aliases to minimize downtime during index replacement operations
- Consider using Index Lifecycle Management (ILM) for automated index deletion based on age or size
- For large indices, deletion might take some time and resources; plan accordingly
- Use the
_all
keyword with caution when deleting multiple indices
Frequently Asked Questions
Q: Can I recover a deleted index in Elasticsearch?
A: No, index deletion is permanent. Always ensure you have a backup or snapshot before deleting an index if the data might be needed later.
Q: How do I delete multiple indices at once?
A: You can use wildcards or comma-separated lists in the DELETE command, e.g., DELETE /index1,index2,index3
or DELETE /test-*
.
Q: Will deleting an index affect other indices or the cluster?
A: Deleting an index only affects that specific index and its data. However, it may temporarily impact cluster performance during the deletion process.
Q: Is there a way to prevent accidental index deletion?
A: Yes, you can use the index.blocks.read_only_allow_delete setting or implement cluster-level settings to prevent accidental deletions.
Q: How long does it take to delete a large index?
A: The time varies based on index size and cluster resources. While Elasticsearch handles this efficiently, very large indices may take several minutes or longer to delete completely.