Using collect command: Why is some data missing?

[welcome]

I am using collect command to transfer data data from one index to another index 
The query is like index=A source=sourceA sourcetype:sourcetypeA host=hostA | collect index=B source=sourceA sourcetype:sourcetypeA host=hostA.
But some data is missing why

[welcome]

Can we have any other command to transfer one index data into another index 

[bowesmana]

Is it possible to re-ingest the data to the new index? Other than that, the collect command should do the trick.

[bowesmana]

What sort of data is missing?

Have you tried using output_format=hec for the collect command 

https://docs.splunk.com/Documentation/Splunk/9.0.3/SearchReference/Collect#arg-options

[welcome]

I am getting events properly but the total number of A events not matching the B events 

[bowesmana]

Can you find some information around the missing data - e.g. does it transfer a fixed number of events, but miss some others.

Are the time stamps the same and is the time window you are searching the same on both indexes?