Removing an Index From MongoDb in Spring - spring

Question

I am trying to delete an index from the database that I put before.
#Indexed(unique = true)
private String name;
After I delete the #Indexed(unique = true), I need to remove it from the MongoDB too. And I need to do it within the Spring. Can I do it with #PostConstruct or something?.

Answer 1

Spring-Data's MongoTemplate has a method to give you IndexOperations for a collection which lets you create and drop indices of a collection.
Attention:
According to db.collection.dropIndex() documentation the drop of a index will lock the whole collection until its dropped and all queries using the index are killed.
Here is an example which deletes an index 'name' from the collection 'products' during app start.
#Component
class IndexManager implements InitializingBean {
private MongoTemplate mongoTemplate;
public IndexManager(MongoTemplate mongoTemplate) {
this.mongoTemplate = mongoTemplate;
}
#Override
public void afterPropertiesSet() {
mongoTemplate.indexOps("products").dropIndex("name");
}
}
There are multiple ways to execute code during spring application startup. More ways to do it can be found here: running-setup-logic-on-startup-in-spring

Answer 2

I solve this with using #PostConstruct. While app is initializing I did remove the index with MongoTemplates. The Code is like this:
#PostConstruct
private void removeIndex() {
IndexOperations indexOperations = mongoTemplate.indexOps(YourEntity.class);
Optional<IndexInfo> indexInfo = indexOperations.getIndexInfo().stream().filter(i->i.getName().equals("name")).findFirst();
if(indexInfo.isPresent()) {
indexOperations.dropIndex("name");
}
}