How this procedure works INTERNALLY???

Question

HI Experts
I have created the below procedure(It is updating 50 million records in decent time) but I have few doubts.
1) I am not commiting till the end. Will it take up the UNDO space. How can I assure that this procedure executes till the end.
2) If i have to increase the UNDO space how should I increase considering 50 million rows.
3) Do I have to consider factors other than UNDO space while running this procedure if yes then wat are they.
4) Suggest me some links where i can find out how sql queries and pl/sql objects works internally.
CREATE OR REPLACE PROCEDURE ACCOUNTS_MIGRATION
IS
TYPE num_new_typ IS TABLE OF accounts.acc_no_new%TYPE ;
TYPE num_old_typ IS TABLE OF accounts.acc_no_old%TYPE ;
TYPE mat_records_typ IS TABLE OF mbk_audittrail.account1%TYPE;
TYPE mat_records_typ_1 IS TABLE OF mbk_audittrail.account2%TYPE;
TYPE mr_records_typ IS TABLE OF mbk_requests.account_no%TYPE;
TYPE mpgn_records_typ IS TABLE OF Mtx_payment_gateway_txn.PAYMENT_METHOD_NUMBER%TYPE;
TYPE mti_records_typ IS TABLE OF Mtx_transaction_items.ACCOUNT_ID%TYPE;
all_num_new num_new_typ:= num_new_typ();
all_num_old num_old_typ:= num_old_typ();
mat_records mat_records_typ:= mat_records_typ();
mat_records_1 mat_records_typ_1:= mat_records_typ_1();
mr_records mr_records_typ:= mr_records_typ();
mpgn_records mpgn_records_typ:= mpgn_records_typ();
mti_records mti_records_typ:= mti_records_typ();
BEGIN
   SELECT ACC_NO_OLD, ACC_NO_NEW bulk collect into all_num_old,all_num_new FROM ACCOUNTS;
   SELECT distinct ACCOUNT1 bulk collect INTO mat_records FROM MBK_AUDITTRAIL where account1 <> ' ';
   SELECT distinct ACCOUNT2 bulk collect INTO mat_records_1 FROM MBK_AUDITTRAIL where account2 <> ' ';
   SELECT distinct account_no bulk collect INTO mr_records FROM Mbk_requests where account_no <> ' ';
   SELECT distinct PAYMENT_METHOD_NUMBER bulk collect INTO mpgn_records FROM Mtx_payment_gateway_txn where PAYMENT_METHOD_NUMBER <> ' ';
   SELECT distinct ACCOUNT_ID bulk collect INTO mti_records FROM Mtx_transaction_items where ACCOUNT_ID <> ' ';
    FORALL i IN 1..mat_records.count
    UPDATE MBK_AUDITTRAIL SET ACCOUNT1=(SELECT ACC_NO_NEW FROM ACCOUNTS WHERE ACC_NO_OLD=mat_records(i) AND ROWNUM=1) WHERE ACCOUNT1=mat_records(i);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for MBK_AUDITTRAIL->ACCOUNT1');
    FORALL j IN 1..mat_records_1.count
    UPDATE MBK_AUDITTRAIL SET ACCOUNT2=(SELECT ACC_NO_NEW FROM ACCOUNTS WHERE ACC_NO_OLD=mat_records_1(j) AND ROWNUM=1) WHERE ACCOUNT2=mat_records(j);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for MBK_AUDITTRAIL->ACCOUNT2');
    FORALL k IN 1..all_num_old.count
    UPDATE MBK_BANK SET ACCOUNT_NO=all_num_new(k) WHERE ACCOUNT_NO=all_num_old(k);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for MBK_BANK->ACCOUNT_NO');
    FORALL l IN 1..all_num_old.count
    UPDATE MBK_CUST_ACCOUNTS SET ACCOUNT_NO=all_num_new(l) WHERE ACCOUNT_NO=all_num_old(l);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for MBK_CUST_ACCOUNTS->ACCOUNT_NO');
    FORALL m IN 1..all_num_old.count
    UPDATE Mtx_Payment_methods SET PAYMENT_METHOD_NUMBER=all_num_new(m) WHERE PAYMENT_METHOD_NUMBER=all_num_old(m);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for Mtx_Payment_methods->PAYMENT_METHOD_NUMBER');
    FORALL n IN 1..mr_records.count
    UPDATE Mbk_requests SET ACCOUNT_NO=(SELECT ACC_NO_NEW FROM ACCOUNTS WHERE ACC_NO_OLD=mr_records(n) AND ROWNUM=1) WHERE ACCOUNT_NO=mr_records(n);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for Mbk_requests->ACCOUNT_NO');
    FORALL o IN 1..mpgn_records.count
    UPDATE Mtx_payment_gateway_txn SET PAYMENT_METHOD_NUMBER=(SELECT ACC_NO_NEW FROM ACCOUNTS WHERE ACC_NO_OLD=mpgn_records(o) AND ROWNUM=1) WHERE PAYMENT_METHOD_NUMBER=mpgn_records(o);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for Mtx_payment_gateway_txn->PAYMENT_METHOD_NUMBER');
    FORALL p IN 1..mti_records.count
    UPDATE Mtx_transaction_items SET ACCOUNT_ID=(SELECT ACC_NO_NEW FROM ACCOUNTS WHERE ACC_NO_OLD=mti_records(p) AND ROWNUM=1) WHERE ACCOUNT_ID=mti_records(p);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for Mtx_transaction_items->ACCOUNT_ID');
    FORALL q IN 1..all_num_old.count
    UPDATE Temp_customer_mgmt SET ACCOUNT_NO=all_num_new(q) WHERE ACCOUNT_NO=all_num_old(q);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for Temp_customer_mgmt->ACCOUNT_NO');
    FORALL r IN 1..all_num_old.count
    UPDATE MTX_HIST_PIN_REGENERATION SET ACCOUNT_NO=all_num_new(r) WHERE ACCOUNT_NO=all_num_old(r);
    DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQL%ROWCOUNT) || ' rows updated for MTX_HIST_PIN_REGENERATION->ACCOUNT_NO');
END;Thanks & Regards
Saurabh Sharma

Answer 1

Remember that besides UNDO you also have to worry about redo !
If you create a new session for every test run at each volume level, you can query V$SESSTAT for the statistiic 'redo size' so as to identify the Bytes of Redo for each volume level. And then extrapolate from there !
Hemant K Chitale
http://hemantoracledba.blogspot.com
Edited by: Hemant K Chitale on Jul 20, 2009 5:02 PM : ADDED Signature