I'm quite new to ElasticSearch. I'm trying to reindex a index in order to rename it. I'm using NEST API v5.4. I saw this example:
var reindex =
elasticClient.Reindex<Customer>(r =>
r.FromIndex("customers-v1")
.ToIndex("customers-v2")
.Query(q => q.MatchAll())
.Scroll("10s")
.CreateIndex(i =>
i.AddMapping<Customer>(m =>
m.Properties(p =>
p.String(n => n.Name(name => name.Zipcode).Index(FieldIndexOption.not_analyzed))))));
Source: http://thomasardal.com/elasticsearch-migrations-with-c-and-nest/
However, I can't reproduce this using NEST 5.4. I think that is to version 2.4. I check the breaking changes of ElasticSearch and try reindexing using this:
Source: https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/nest-breaking-changes.html
public method Nest.ReindexDescriptor..ctor Declaration changed (Breaking)
2.x: public .ctor(IndexName from, IndexName to) 5.x: public .ctor()
var reindex = new client.Reindex(oldIndexName, newIndexName);
But this did not work too. I also search for documentation but i didn't find any code on c#, just JSON Source: https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html)
Can someone give me a example how to reindex using NEST 5.4 on C#?
Thanks in advance! :slight_smile:
After search for 2 long days I found out the solution to reindex a index. In order to solve future problems, I'll provide my solution.
Nest Version - 5.4
var reindex = client.Reindex<object>(r => r
.BackPressureFactor(10)
// ScrollAll - Scroll all the documents of the index and store it for 1minute
.ScrollAll("1m", 2, s => s
.Search(ss => ss
.Index(oldIndexName)
.AllTypes())
// there needs to be some degree of parallelism for this to work
.MaxDegreeOfParallelism(4))
.CreateIndex(c => c
// New index here
.Index(newIndexName)
.Settings(
// settings goes here)
.Mappings(
// mappings goes here))
.BulkAll(b => b
// New index here!
.Index(newIndexName)
.Size(100)
.MaxDegreeOfParallelism(2)
.RefreshOnCompleted()));
the ReIndex method returns a cold IObservable on which you have to call .Subscribe() to kick off everything.
So, you need to add it to your code:
var o = new ReindexObserver(
onError: (e) => { //do something },
onCompleted: () => { //do something });
reindex.Subscribe(o);
Useful links to check this are: