ElasticSearch reindexing with selected fields result into addition of non selected empty field - amazon-web-services

Question

Scenario:
We are using AWS ElasticSearch 6.8. We got an index (index-A) with a mapping structure consist of multiple nested objects and JSON hierarchy. We need to create new index (index-B) and move all documents from index-A to index-B.
We need to create index-B with only specific fields.
We need to rename field names while reindexing
e.g.
index-A mapping:
{
"userdata": {
"properties": {
"payload": {
"type": "object",
"properties": {
"Alldata": {
"Username": {
"type": "keyword"
},
"Designation": {
"type": "keyword"
},
"Company": {
"type": "keyword"
},
"Region": {
"type": "keyword"
}
}
}
}
}
}}
Expected structure of index-B mapping after reindexing with rename (Company-cnm, Region-rg) :-
{
"userdata": {
"properties": {
"cnm": {
"type": "keyword"
},
"rg": {
"type": "keyword"
}
}
}}
Steps we are Following:
First we are using Create index API to create index-B with above mapping structure
Once index is created we are creating an ingest pipeline.
PUT ElasticSearch domain endpoint/_ingest/pipeline/my_rename_pipeline
{
"description": "rename field pipeline",
"processors": [{
"rename": {
"field": "payload.Company",
"target_field": "cnm",
"ignore_missing": true
}
},
{
"rename": {
"field": "payload.Region",
"target_field": "rg",
"ignore_missing": true
}
}
]
}
Perform reindexing operation, payload for the same below
let reindexParams = {
wait_for_completion: false,
slices: "auto",
body: {
"conflicts": "proceed",
"source": {
"size": 8000,
"index": "index-A",
"_source": ["payload.Company", "payload.Region"]
},
"dest": {
"index": "index-B",
"pipeline": "my_rename_pipeline",
"version_type": "external"
}
}
};
Problem:
Once the reindexing is complete as expected all documents transferred to new index with renamed fields but there is one additional field which is not selected. As you can see below the "payload" object with metadata is also added to the new index after reindexing. This field is empty and consist of no data.
index-B looks like below after reindexing:
{
"userdata": {
"properties": {
"cnm": {
"type": "keyword"
},
"rg": {
"type": "keyword"
},
"payload": {
"properties": {
"Alldata": {
"type": "object"
}
}
}
}
}}
We are unable to find the workaround and need help how to stop this field from creating. Any help will be appreciated.

Answer 1

Great job!! You're almost there, you simply need to remove the payload field within your pipeline using the remove processor and you're good:
{
"description": "rename field pipeline",
"processors": [
{
"rename": {
"field": "payload.Company",
"target_field": "cnm",
"ignore_missing": true
}
},
{
"rename": {
"field": "payload.Region",
"target_field": "rg",
"ignore_missing": true
}
},
{
"remove": { <--- add this processor
"field": "payload"
}
}
]
}