Reindex without replica & documents are removed after reindexing

[da-head0 (Dahye)]

Hi, I used methods below to reindex ES index, for change number of shards & replica.

curl -X PUT "ip:port/argocd-log-2022-05-29-reindexed?pretty" -H 'Content-Type: application/json' -d'
{
    "settings" : {
        "index" : {
            "number_of_shards" : 1, 
            "number_of_replicas" : 0 
        }
    }
}'

curl -X POST "ip:port/_reindex?pretty" -H 'Content-Type: application/json' -d'
{
  "source": {
    "index": "argocd-log-2022-05-29"
  },
  "dest": {
    "index": "argocd-log-2022-05-29-reindexed"
  }
}
'


curl -X DELETE "ip:port/argocd-log-2022-05-29"


curl -X PUT "ip:port/argocd-log-2022-05-29?pretty" -H 'Content-Type: application/json' -d'
{
    "settings" : {
        "index" : {
            "number_of_shards" : 1, 
            "number_of_replicas" : 0 
        }
    }
}'

curl -X POST "ip:port/_reindex?pretty" -H 'Content-Type: application/json' -d'
{
  "source": {
    "index": "argocd-log-2022-05-29-reindexed"
  },
  "dest": {
    "index": "argocd-log-2022-05-29"
  }
}
'


curl -X DELETE "ip:port/argocd-log-2022-05-29-reindexed"

But I found out this method reindex 6GB index(2 shards, 1 replica) -> to 11GB index (1 shard, 0 replica). So I thought in that way, documents in replica are also reindexed to new index.

Is it true?

I also found out reindexing in the way I used, sometimes(not always) only recent documents are survived, and the documents before reindexed are removed.
Can somebody tell me what I did wrong?

[warkolm (Mark Walkom)]

@da-head0

So I thought in that way, documents in replica are also reindexed to new index.

Is it true?

No, that's not possible. We'd need to understand the mappings you are using to comment further.

However why don't you just use Split index API | Elasticsearch Guide [8.2] | Elastic (or Shrink index API | Elasticsearch Guide [8.2] | Elastic)?