Reproduce steps:

See SUPPORT-689

Problem:

Updating HistoricActivityInstance throws Arithmetic overflow/exception when calculating duration on DB2.
Cause is DB2 threats the values before addition as Integer not BigInteger so an Overflow occurs.

Expected behavior:

Works.

Hints (optional):

All mappings in history where we calculate the duration must be checked and adjusted like
UPDATE
ACT_HI_ACTINST
SET
DURATION_ = --->>>> (CAST(123456775676890 AS BIGINT) + CAST(1235000000 AS BIGINT)) <<<<---
WHERE
TASK_ID_ = '96fcea2d-1150-11e3-98fa-028037ec0200'