# Painless script\_exception : ctx.\_source : null\_pointer\_exception
**URL:** https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885
**Category:** Elasticsearch
**Created:** [February 18, 2019, 6:17pm UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885 "2019-02-18T18:17:22Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@achile](https://discuss.elastic.co/u/achile)
#### Post date: [February 18, 2019, 6:17pm UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885/1 "2019-02-18T18:17:22Z")
Hello,
I am working with version elasticsearch 6.5.4, I added a new field to my existing index and I want to give it a value equal to the sum of some other fields. I used the following query in Kibana but it does not work, only the first field of the addition operation is recognized :
POST my\_index/\_update\_by\_query
{
"script": {
"lang": "painless",
"source": "ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_comments']"
},
"query": {
"match\_all": {}
}
}
######Result :
{
"error": {
"root\_cause": [
{
"type": "script\_exception",
"reason": "runtime error",
"script\_stack": [
"ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_comments']",
" ^---- HERE"
],
"script": "ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_comments']",
"lang": "painless"
}
],
"type": "script\_exception",
"reason": "runtime error",
"script\_stack": [
"ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_comments']",
" ^---- HERE"
],
"ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_comments']",
"lang": "painless",
"caused\_by": {
"type": "null\_pointer\_exception",
"reason": null
}
},
"status": 500
}
#######
thank you.
---
### Author:  [@val](https://discuss.elastic.co/u/val)
#### Post date: [February 18, 2019, 7:19pm UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885/2 "2019-02-18T19:19:35Z")
Are you certain that all of your documents have a non-null `num_comments` field?
---
### Author:  [@achile](https://discuss.elastic.co/u/achile)
#### Post date: [February 18, 2019, 7:47pm UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885/3 "2019-02-18T19:47:45Z")
thank you for your reply;
The fields I would like to add are by default equal to 0 (type: long). If I change the order of the fields on the addition operation, the second field is pointed with the error.
I tested this script on other configuration and it works, now I do not know what is the origin of the problem.
just to correct:
ctx.\_source['num\_attractivity']=ctx.\_source['num\_comments']+ctx.\_source['num\_reactions']
---
### Author:  [@val](https://discuss.elastic.co/u/val)
#### Post date: [February 19, 2019, 4:33am UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885/4 "2019-02-19T04:33:07Z")
What I meant is that if any of those two fields is not present in any source document, then it is not 0 by default, it is null. So you either need to make sure the each document has both of those fields or to protect against null pointer exceptions in your code.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 19, 2019, 4:33am UTC](https://discuss.elastic.co/t/painless-script-exception-ctx-source-null-pointer-exception/168885/5 "2019-03-19T04:33:09Z")
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