### Author:  [@Matt\_Shallow](https://discuss.elastic.co/u/Matt_Shallow)
#### Post date: [October 17, 2024, 5:04pm UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/1 "2024-10-17T17:04:41Z")
I have been following a bulk update example to do a bulk update on my index however I get the following error:
> Validation Failed: 1: can't provide both script and doc;
The below code is what is giving the error.
```auto
var bulkResponse = client.Bulk(b => b
.Index("my_index")
.UpdateMany(my_dictionary, (descriptor, dict) => descriptor
.Id(dict.Key)
.Script(s => s
.Source("ctx._source.list.add(params.item)")
.Params(p => p
.Add("item", dict.Value)
)
)
)
);
```
Would love some suggestions on how I can do a bulk update on multiple documents. The below works fine for single update on a document. I just need to apply it to bulk update.
```auto
var response = await _client.UpdateAsync(
index:"my_index",
id:"my_id",
u => u.Script(s => s
.Source("ctx._source.list.add(params.item)")
.Params(p => p
.Add("item", myObject.Value))));
```
---
### Author:  [@ashishtiwari1993](https://discuss.elastic.co/u/ashishtiwari1993)
#### Post date: [October 18, 2024, 9:29am UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/2 "2024-10-18T09:29:28Z")
Hi @Matt_Shallow, Welcome to the Elastic Community.
1. May i know which version of Elastic you're using?
2. Also are you referring this [javascript client](https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/api-reference.html#_bulk) ? It looks `UpdateMany` is not the part of it.
---
### Author:  [@Matt\_Shallow](https://discuss.elastic.co/u/Matt_Shallow)
#### Post date: [October 18, 2024, 9:41am UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/3 "2024-10-18T09:41:37Z")
Hi @ashishtiwari1993 . I am using the latest version of Elastic. Doing some exploration work.
I am using the latest available .NET Elastic client library. Documentation seems pretty lax on Bulk Api elastic docs for .NET. Even entries deleted š§ See below link.
Essentially, what I am trying to do is bulk update multiple documents adding a new item to a list I have in each of these documents. I am iterating through a dictionary whose Key = DocumentID and Value is the item to be added to the documents list.
Bulk UpdateMany seems exactly what I need but I am getting that error. So I need to somehow restructure the Query which I need help with š
> **[Indexing documents | Elasticsearch .NET Client \[8.15\] | Elastic](https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/indexing-documents.html)**
---
### Author:  [@flobernd](https://discuss.elastic.co/u/flobernd)
#### Post date: [October 21, 2024, 7:20am UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/4 "2024-10-21T07:20:44Z")
Hi @Matt_Shallow,
you are hitting a very specific limitation of the `UpdateMany` API here.
The `_bulk` endpoint accepts either `script` or `doc`, but not both. In the client, we internally check which variant the user has provided. For this, we compare the value of `script` or `doc` to `null`.
In your specific case, `TDocument` is of type `KeyValuePair<,>` which is a value type. The `null` check yields incorrect results as value types are never `null`.
As a workaround, you could convert your `KeyValuePair<,>` to a reference type. This will cause a few extra allocations, but is currently the only way to make the bulk API work in the way you want:
```csharp
var bulkResponse = await client.BulkAsync(b => b
.Index("persons")
.UpdateMany(my_dictionary.Select(x => new { x.Key, x.Value }), (descriptor, dict) => descriptor
.Id(dict.Key)
.Script(s => s
.Source("ctx._source.list.add(params.item)")
.Params(p => p
.Add("item", dict.Value)
)
)
)
);
```
---
### Author:  [@Matt\_Shallow](https://discuss.elastic.co/u/Matt_Shallow)
#### Post date: [October 21, 2024, 4:19pm UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/5 "2024-10-21T16:19:33Z")
Thanks @flobernd for taking a look and solution. Let me give that a whirl and get back to you.
I will be doing some performance checks on different ways to store and then query the data in elastic so possibly my current approach might not be the way forward.
Thanks.
---
### Author:  [@Matt\_Shallow](https://discuss.elastic.co/u/Matt_Shallow)
#### Post date: [October 22, 2024, 12:14pm UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/6 "2024-10-22T12:14:21Z")
@flobernd This worked great and not really any noticeable performance issues. I appreciate you explaining clearly why I was getting that specific error and for providing a solution.
Thanks\<
Matt
---
### Author:  [@flobernd](https://discuss.elastic.co/u/flobernd)
#### Post date: [October 22, 2024, 6:06pm UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/7 "2024-10-22T18:06:49Z")
Thanks for updating the issue! Iām glad that the solution works for you š
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 19, 2024, 6:07pm UTC](https://discuss.elastic.co/t/best-way-to-do-a-bulk-update-with-script/369017/8 "2024-11-19T18:07:09Z")
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