Cursor in mysql stored procedure executes only 1 iteration - mysql

Question

I have been struck in this stored procedure for 2 days now.
Here's the code
BEGIN
DECLARE in_township_id INT DEFAULT 2;
DECLARE in_billing_month INT DEFAULT 1;
DECLARE in_billing_month_string VARCHAR(15) DEFAULT 'January';
DECLARE in_billing_year INT DEFAULT 2016;
DECLARE in_account_id INT DEFAULT 1;
DECLARE out_status INT DEFAULT 0;
DECLARE in_invoice_date DATETIME DEFAULT CURRENT_DATE();
DECLARE _no_flats INT;
DECLARE _current_month_data_exists INT;
DECLARE _flat_id INT;
DECLARE _current_billing_month, _current_billing_year INT;
DECLARE _next_billing_month, _next_billing_year INT;
DECLARE _current_balance, _new_balance FLOAT DEFAULT 0;
DECLARE _maintenance, _power_backup, _service_tax, _penalty FLOAT DEFAULT 0;
DECLARE _maintenance_price, _power_backup_price, _service_tax_price, _balance_price, _penalty_price FLOAT DEFAULT 0;
DECLARE _consumed_units INT;
DECLARE _penal_interest_remark, _maintenance_bill_remark, _power_backup_remark, _service_tax_remark, _maintenance_account_remark VARCHAR(100);
DECLARE _total_penalty, _total_maintenance, _total_power_backup, _total_service_tax FLOAT DEFAULT 0;
DECLARE _all_flats_cursor CURSOR FOR SELECT id FROM flat_resident_v WHERE township_id=2;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _no_flats=1;
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
ROLLBACK;
SET out_status=2;
SELECT 'An error has occurred, operation rollbacked and the stored procedure was terminated';
END;
START TRANSACTION;
SET _current_billing_month=in_billing_month;
SET _current_billing_year=in_billing_year;
SET _next_billing_month=in_billing_month;
SET _next_billing_year=in_billing_year;
IF in_billing_month=1 THEN
SET _current_billing_month=12;
SET _current_billing_year=in_billing_year-1;
END IF;
IF in_billing_month=12 THEN
SET _next_billing_month=1;
SET _next_billing_year=in_billing_year+1;
ELSE
SET _next_billing_month = in_billing_month+1;
END IF;
SELECT CONCAT('On account of billing month ', in_billing_month_string) INTO _maintenance_account_remark;
SELECT penalty, rate_maintenance, rate_power_backup, service_tax_rate
INTO _penalty, _maintenance, _power_backup, _service_tax FROM account_master WHERE id=in_account_id;
SELECT CONCAT('Charged # ', _penalty*1200, '%') INTO _penal_interest_remark;
SELECT CONCAT('Charged # Rs. ', _maintenance, '/sq. feet') INTO _maintenance_bill_remark;
SELECT CONCAT('Charged # Rs. ', _power_backup, '/unit') INTO _power_backup_remark;
SELECT CONCAT('Charged # ', _service_tax_price*100, '%') INTO _service_tax_remark;
SET out_status = 0;
INSERT INTO temp(value1, value2) VALUES('SUCCESS', 'Initialization Completed');
OPEN _all_flats_cursor;
SET _no_flats=0;
ALL_FLATS_LOOP: LOOP
FETCH _all_flats_cursor INTO _flat_id;
IF _no_flats=1 THEN
INSERT INTO temp(value1, value2) VALUES('LOOP BREAK', _no_flats);
LEAVE ALL_FLATS_LOOP;
END IF;
IF _no_flats=0 THEN
INSERT INTO temp(value1, value2) VALUES('INSIDE LOOP', _no_flats);
INSERT INTO temp(value1, value2) VALUES('FLAT_ID', _flat_id);
SELECT count(FLATS.id) INTO _current_month_data_exists FROM account_flat_ledger as FLATS
WHERE FLATS.flat_id=_flat_id AND FLATS.debit_month=in_billing_month
AND FLATS.debit_year=in_billing_year FOR UPDATE;
IF _current_month_data_exists=0 THEN
SET out_status = 1;
INSERT INTO temp(value1, value2) VALUES('_current_month_data_exists', 'FAILED: Data not exists for billing year');
LEAVE ALL_FLATS_LOOP;
END IF;
SELECT consumed_units INTO _consumed_units FROM account_power_backup_usage
WHERE flat_id=_flat_id AND month=in_billing_month AND year=in_billing_year;
INSERT INTO temp(value1, value2) VALUES('SUCCESS', 'Power Ok');
SELECT balance INTO _current_balance FROM account_flat_ledger as FLATS
WHERE FLATS.flat_id=_flat_id AND FLATS.debit_month=_current_billing_month AND FLATS.debit_year=_current_billing_year FOR UPDATE;
IF _current_balance>0 THEN
SET _penalty_price = _penalty*_current_balance;
END IF;
SET _maintenance_price = _maintenance*1000;
SET _power_backup_price = _power_backup*_consumed_units;
SET _service_tax_price = _service_tax * (_maintenance+_power_backup);
SET _new_balance = _current_balance + _penalty + _maintenance + _power_backup + _service_tax;
INSERT INTO temp(value1, value2) VALUES('SUCCESS', 'All Values Set');
UPDATE account_flat_ledger SET penal_interest=_penalty_price, maintenance_bill=_maintenance_price, service_tax=_service_tax_price,
power_backup=_power_backup_price, opening_balance=_current_balance,received_amount=0, balance=_new_balance,
debit_date=CURDATE(), penal_interest_remark=_penal_interest_remark, maintenance_bill_remark=_maintenance_bill_remark,
power_backup_remark=_power_backup_remark, service_tax_remark=_service_tax_remark
WHERE flat_id=_flat_id AND debit_month=in_billing_month AND debit_year=in_billing_year;
INSERT INTO account_flat_ledger(flat_id, debit_month, debit_year)
VALUES(_flat_id, _next_billing_month, _next_billing_year);
INSERT INTO temp(value1, value2) VALUES('SUCCESS', 'Insertion of new Flats OK');
SET _total_maintenance = _total_maintenance + (_maintenance_price
+ _power_backup_price + _service_tax_price + _penalty_price);
SET _total_penalty = _total_penalty + _penalty_price;
SET _total_power_backup = _total_power_backup + _power_backup_price;
SET _total_service_tax = _total_service_tax + _service_tax_price;
INSERT INTO temp(value1, value2) VALUES('SUCCESS', 'Flat over');
END IF;
END LOOP ;
CLOSE _all_flats_cursor;
IF out_status != 0 THEN
ROLLBACK;
END IF;
SELECT #out_status;
END IF;
COMMIT;
END
Previously I have done this whole thing using Java code (using ResultSets and PreparedStatements). But someone told me to use stored procedure for this purpose to make things handy and efficient.
Problem: The loop i.e. Cursor executes only ones, but there are 3 records present in the table.
I used logging into temp table to trace the error but couldn't find.