Different execution plan for the same sql statement

Hi all,

When I check the same sql statement in different systems,   P system and Q system.

It shows different execution plan for inner join

Sql statement

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Excution plan

For system P    the value of MANDT is 1     table EKPO accessed first with full table scan.

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For system Q    the value of MANDT is 4     table EKKO accessed first with index EKKO~1(in P also has this index)

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Data volume in Q is a little bit larger than P.

Could you please help to find out why there is such a difference?  which one is correct?

How the optimizer works when process the inner join for maxDB?

Thanks & Regards,

Chris