Subsearch append question !!

[zacksoft]

I have search query that looked like this,

index = aries sourcetype = onezone 
| fields aaa baa
| stats values(aaa) as aaa 
| table aaa
append
   [ search index = leo sourcetype =twofone
        | fields ccc
        | stats ccc ]
| stats value(aaa) as sd , values(ccc) as cc

Now the optimizedQuery option of Splunk changed the "append" command in the search and replaced it with  to "[  | " search (index = leo  sourcetype=twofone  etc..etc....".....
And my output doesn't change. Both version has same output.

My question is, in the world of subsearches is using "append" the same as  using " [ | search (index = ....."

Is using ""[ | "" better in terms of performnce than using "append "  ?

[richgalloway]

How Splunk processes a query internally does not necessarily imply you should or can write that query and differently.

If you ran this query you would get far different results (if any at all) than with the original.

index = aries sourcetype = onezone 
| fields aaa baa
| stats values(aaa) as aaa 
| table aaa
[ search index = leo sourcetype =twofone
    | fields ccc
    | stats ccc ]
| stats value(aaa) as sd , values(ccc) as cc