# Can't specify a subobject field in a path as the \_id field
**URL:** https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083
**Category:** Elasticsearch
**Created:** [September 20, 2012, 9:28pm UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083 "2012-09-20T21:28:51Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@phill](https://discuss.elastic.co/u/phill)
#### Post date: [September 20, 2012, 9:28pm UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/1 "2012-09-20T21:28:51Z")
I was designing an ES document and thought I'd use a \_id : { path : {
... } } specification to pick a value I thought was really unique.
I have confidence that values are all unique. It is a SHA-256 based on
the original file. We have used this in our previous system to Identify
duplicate files.
I decided to index the hash field within an object, so the definition
looks like:
But this doesn't work.
"myDocument": {
\_id : { path : _"Text.hash"_ }
,properties: {
"originalPath": { type:"string", store:1,
index:"not\_analyzed" }
...
,_Text_ : {
,properties: {
_hash: { type:"string", store:1, index:"not\_analyzed" }_
,length: { type:"long", store:1 }
...
}
}
}
}
When I specify the field to use as one within the Text object, as above,
the index ends up with 1 document in it! And it's \_id is "[".
[http://localhost:9200/\_search?pretty=1](http://localhost:9200/_search?pretty=1)
{
"took" : 2,
"timed\_out" : false,
"\_shards" : {
"total" : 3,
"successful" : 3,
"failed" : 0
},
"hits" : {
-
```
"total" : 1,*
```
"max\_score" : 1.0,
"hits" : [ {
"\_index" : "dragon0",
"\_type" : "myDocument",
_"\_id" : "["_,
"\_score" : 1.0
} ]
}
}
If I move the hash field outside of the subobject Text, I get unique
documents.
So This does work.
"myDocument": {
\_id : { path : _"hash"_ }
,properties: {
"originalPath": { type:"string", store:1,
index:"not\_analyzed" }
_,hash: { type:"string", store:1, index:"not\_analyzed" }_
...
,Text : {
properties: {
...
,length: { type:"long", store:1 }
...
}
}
}
}
If I again search for everything with.
[http://localhost:9200/\_search?pretty=1](http://localhost:9200/_search?pretty=1)
I get all the 200 documents I inserted.
{
"took" : 1,
"timed\_out" : false,
"\_shards" : {
"total" : 3,
"successful" : 3,
"failed" : 0
},
"hits" : {
-
```
"total" : 200,*
```
"max\_score" : 1.0,
"hits" : [ {
"\_index" : "dragon0",
"\_type" : "myDocument",
_"\_id" : "FjhwleNbQhyDh4XzB7k7BA",_
"\_score" : 1.0
}, {
"\_index" : "dragon0",
"\_type" : "myDocument",
_"\_id" : "OVqLwly7RKmQ6R59q8JQOA",_
"\_score" : 1.0
}, {
...
I think this is a bug. If not please
Is this enough information to recreate the problem? I didn't have time
to gist it today.
-Paul
--
---
### Author:  [@Clinton\_Gormley](https://discuss.elastic.co/u/Clinton_Gormley)
#### Post date: [September 21, 2012, 9:11am UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/2 "2012-09-21T09:11:48Z")
Hi Paul
> I think this is a bug. If not please
> Is this enough information to recreate the problem? I didn't have time
> to gist it today.
It's quite difficult to follow when the JSON isn't formatted properly
etc. Please can you gist a curl recreation that we can copy and paste
to run, so that we can examine it locally?
ta
clint
> -Paul
--
---
### Author:  [@Clinton\_Gormley](https://discuss.elastic.co/u/Clinton_Gormley)
#### Post date: [September 21, 2012, 9:19am UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/3 "2012-09-21T09:19:21Z")
Hi Paul
> > I think this is a bug. If not please
> > Is this enough information to recreate the problem? I didn't have time
> > to gist it today.
>
> It's quite difficult to follow when the JSON isn't formatted properly
> etc. Please can you gist a curl recreation that we can copy and paste
> to run, so that we can examine it locally?
Actually, it looks like your \_id path may be putting to an array? I
would say that you are doing something illegal, but that ES should catch
the problem and throw an error.
Opened as [The `_id` path should not allow arrays · Issue #2275 · elastic/elasticsearch · GitHub](https://github.com/elasticsearch/elasticsearch/issues/2275)
curl -XPUT '[http://127.0.0.1:9200/test/?pretty=1](http://127.0.0.1:9200/test/?pretty=1)' -d '
{
"mappings" : {
"test" : {
"\_id" : {
"path" : "foo.bar"
}
}
}
}
'
### THIS WORKS
curl -XPOST '[http://127.0.0.1:9200/test/test?pretty=1](http://127.0.0.1:9200/test/test?pretty=1)' -d '
{
"foo" : {
"bar" : 1,
"baz" : "xx"
}
}
'
# [Fri Sep 21 11:14:21 2012] Response:
# {
# "ok" : true,
# "\_index" : "test",
# "\_id" : "1",
# "\_type" : "test",
# "\_version" : 1
# }
### THIS DOESN'T
curl -XPOST '[http://127.0.0.1:9200/test/test?pretty=1](http://127.0.0.1:9200/test/test?pretty=1)' -d '
{
"foo" : {
"bar" : [
2
],
"baz" : "xx"
}
}
'
# [Fri Sep 21 11:14:23 2012] Response:
# {
# "ok" : true,
# "\_index" : "test",
# "\_id" : "[",
# "\_type" : "test",
# "\_version" : 1
# }
--
---
### Author:  [@phill](https://discuss.elastic.co/u/phill)
#### Post date: [September 21, 2012, 5:10pm UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/4 "2012-09-21T17:10:09Z")
After looking at this more, my assumption now is that the real rule may
be that the \_id path should point at a numeric value ready for direct
use as an ID.
I think your are right, it should complain about my naive, but illegal
choice of fields to map to the ID, instead of whatever silent
alternative path it took.
-Paul
On 9/21/2012 2:19 AM, Clinton Gormley wrote:
> Hi Paul
>
> > > I think this is a bug. If not please
> > > Is this enough information to recreate the problem? I didn't have time
> > > to gist it today.
> > > It's quite difficult to follow when the JSON isn't formatted properly
> > > etc. Please can you gist a curl recreation that we can copy and paste
> > > to run, so that we can examine it locally?
> > > Actually, it looks like your \_id path may be putting to an array? I
> > > would say that you are doing something illegal, but that ES should catch
> > > the problem and throw an error.
>
> Opened as [The `_id` path should not allow arrays · Issue #2275 · elastic/elasticsearch · GitHub](https://github.com/elasticsearch/elasticsearch/issues/2275)
>
> curl -XPUT '[http://127.0.0.1:9200/test/?pretty=1](http://127.0.0.1:9200/test/?pretty=1)' -d '
> {
> "mappings" : {
> "test" : {
> "\_id" : {
> "path" : "foo.bar"
> }
> }
> }
> }
> '
>
> ### THIS WORKS
>
> curl -XPOST '[http://127.0.0.1:9200/test/test?pretty=1](http://127.0.0.1:9200/test/test?pretty=1)' -d '
> {
> "foo" : {
> "bar" : 1,
> "baz" : "xx"
> }
> }
> '
>
> # [Fri Sep 21 11:14:21 2012] Response:
>
> # {
>
> # "ok" : true,
>
> # "\_index" : "test",
>
> # "\_id" : "1",
>
> # "\_type" : "test",
>
> # "\_version" : 1
>
> # }
>
> ### THIS DOESN'T
>
> curl -XPOST '[http://127.0.0.1:9200/test/test?pretty=1](http://127.0.0.1:9200/test/test?pretty=1)' -d '
> {
> "foo" : {
> "bar" : [
> 2
> ],
> "baz" : "xx"
> }
> }
> '
>
> # [Fri Sep 21 11:14:23 2012] Response:
>
> # {
>
> # "ok" : true,
>
> # "\_index" : "test",
>
> # "\_id" : "[",
>
> # "\_type" : "test",
>
> # "\_version" : 1
>
> # }
--
---
### Author:  [@phill](https://discuss.elastic.co/u/phill)
#### Post date: [September 27, 2012, 7:31pm UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/5 "2012-09-27T19:31:01Z")
Followup to this post, so as not to throw anyone else off. You CAN use
a non-numeric field as the \_id, just not one nested withing another
(sub)object at this time, so the bug is either to complain or use the
field properly.
-Paul
On 9/21/2012 10:11 AM, P. Hill wrote:
> After looking at this more, my assumption now is that the real rule
> may be that the \_id path should point at a numeric value ready for
> direct use as an ID.
> I think your are right, it should complain about my naive, but illegal
> choice of fields to map to the ID, instead of whatever silent
> alternative path it took.
--
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 3:11am UTC](https://discuss.elastic.co/t/cant-specify-a-subobject-field-in-a-path-as-the--id-field/9083/6 "2017-07-06T03:11:07Z")