optimize parameters

At the customer I working right now, they asked me to look at a query that did run in a test EBS database, but wouldn't run in a developer EBS database.
When running the query in the dev database, the session seems to hang and no records are returned.
So, first I looked at the explain plan from the query running in the test database. It looked like this..

Operation Object Name Rows Bytes Cost Object Node In/Out PStart PStop
SELECT STATEMENT Optimizer Mode=CHOOSE 339 K 103359
NESTED LOOPS 339 K 8 M 103359
TABLE ACCESS BY INDEX ROWID CSI.CSI_T_EXTEND_ATTRIBS 339 K 6 M 103358
INDEX RANGE SCAN CSI.CSI_T_EXTEND_ATTRIBS_N02 339 K 4066
INDEX UNIQUE SCAN CSI.CSI_T_TXN_LINE_DETAILS_U01 1 6

Then I tried running the query in the dev database and the explain plan looked like..

Operation Object Name Rows Bytes Cost Object Node In/Out PStart PStop
SELECT STATEMENT Optimizer Mode=CHOOSE 339 K 56396
HASH JOIN 339 K 8 M 56396
TABLE ACCESS BY INDEX ROWID CSI.CSI_T_EXTEND_ATTRIBS 339 K 6 M 7
INDEX RANGE SCAN APPS.XXX_CSI_T_EXTEND_ATTRIBS_N1 339 K 2
TABLE ACCESS FULL CSI.CSI_T_TXN_LINE_DETAILS 11 M 64 M 51170

It seems in the dev database the query is doing a full table scan, instead of indexed scan in the test database. Also in the test database a NESTED LOOP is used, while the dev database uses a HASH JOIN ??
I focussed on the last finding and searched for a reason why the query should use HASH JOIN instead of a NESTED LOOP.
I found out the following two init.ora parameters were different in the dev database, the optimizer_index_caching parameter and the optimizer_index_cost_adj parameter. So, I tried running the query after I changed my session settings..

SQL> alter session set optimizer_index_caching=x;

SQL> alter session set optimizer_index_cost_adj=x;

And this time the query returned the desired rows ! Next step is to edited the init.ora so the whole dev environment can use these settings...