# Not able to create indexes using json format on mongodb and unable to generate change logs on existing mongodb databases to capture the changes
**URL:** https://forum.liquibase.org/t/not-able-to-create-indexes-using-json-format-on-mongodb-and-unable-to-generate-change-logs-on-existing-mongodb-databases-to-capture-the-changes/7444
**Category:** General Discussion
**Created:** [October 20, 2022, 12:40pm UTC](https://forum.liquibase.org/t/not-able-to-create-indexes-using-json-format-on-mongodb-and-unable-to-generate-change-logs-on-existing-mongodb-databases-to-capture-the-changes/7444 "2022-10-20T12:40:20Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@kmkrishna1223](https://forum.liquibase.org/u/kmkrishna1223)
#### Post date: [October 20, 2022, 12:40pm UTC](https://forum.liquibase.org/t/not-able-to-create-indexes-using-json-format-on-mongodb-and-unable-to-generate-change-logs-on-existing-mongodb-databases-to-capture-the-changes/7444/1 "2022-10-20T12:40:20Z")
Not able to create indexes using json format on mongodb and unable to generate change logs on existing mongodb databases to capture the changes
```auto
{
"databaseChangeLog": [{
"property": {
"name": "collection.name",
"value": "person3"
}
},
{
"changeSet": {
"id": "12334d",
"author": "murali",
"changes": [{
"createIndex": {
"collectionName": "${collection.name}",
"indexQuery": { "clientId": 1,"type": 1 },
"indexOptions": {
"$rawJson": {
"unique": true,
"name": "new_index_key"
}
}
}
}]
}
}
]
}
... 67 more
Caused by: com.mongodb.MongoCommandException: Command failed with error 67 (CannotCreateIndex): 'Error in specification { key: {} } :: caused by :: Index keys cannot be empty.' on server localhost:27017. The full response is {"ok": 0.0, "errmsg": "Error in specification { key: {} } :: caused by :: Index keys cannot be empty.", "code": 67, "codeName": "CannotCreateIndex"}
at com.mongodb.internal.connection.ProtocolHelper.getCommandFailureException(ProtocolHelper.java:195)
at com.mongodb.internal.connection.InternalStreamConnection.receiveCommandMessageResponse(InternalStreamConnection.java:400)
at com.mongodb.internal.connection.InternalStreamConnection.sendAndReceive(InternalStreamConnection.java:324)
```
---
### Author:  [@tabbyfoo](https://forum.liquibase.org/u/tabbyfoo)
#### Post date: [October 26, 2022, 5:42pm UTC](https://forum.liquibase.org/t/not-able-to-create-indexes-using-json-format-on-mongodb-and-unable-to-generate-change-logs-on-existing-mongodb-databases-to-capture-the-changes/7444/2 "2022-10-26T17:42:31Z")
> [@kmkrishna1223](#):
>
> `Command failed with error 67 (CannotCreateIndex)`
Hi @kmkrishna1223 - Welcome to the Liquibase Community!
I found an issue with a similar error that was related to the size that the index is or might become over time. This one has a lot of discussion on StackOverflow with a couple of suggested answers and comments with helpful information. Have you seen this one already? [indexing - Mongodb - Multiple text index: Index key pattern too large error code 67 - Stack Overflow](https://stackoverflow.com/questions/25336130/mongodb-multiple-text-index-index-key-pattern-too-large-error-code-67)
-Tabby
---
### Author:  [@kmkrishna1223](https://forum.liquibase.org/u/kmkrishna1223)
#### Post date: [October 27, 2022, 3:40am UTC](https://forum.liquibase.org/t/not-able-to-create-indexes-using-json-format-on-mongodb-and-unable-to-generate-change-logs-on-existing-mongodb-databases-to-capture-the-changes/7444/3 "2022-10-27T03:40:49Z")
Thanks for the response.
I am not using text indexes and its working with XML change log .
Even tried with different approaches with json its failed to form keys as follows
```auto
[2022-10-27 03:39:24] FINE [liquibase.ext] Executing Statement: db.runCommand({"createIndexes": "person3", "indexes": [{**"key": {}}]}**);
```