Help me optimize this query

[Manish]

I am trying to execute this query and it is failing with Table is full error
(I know I can make temp tables big).
update t1, t2
set t1.XXX=1
where t1.YYY=t2.ZZZZ and t2.AAAA like '%X%';

My t1 has 10,00,000+ records and t2 has about 70,000 recorsds. I would like
to know how can I optimize this query?
What are the parmeters for this optimization? Can someone give me links
where I can read up about such optimizations for update query.

TIA,
- Manish