Can I do?
Start transaction;
insert into db1.table1 (field1) values (100),(100);
insert into db2.table2 (field2) values (100),(100);
commit;
Yes you can:
MySQL 5.0.3 and up provides server-side support for XA transactions. Currently, this support is available for the InnoDB storage engine. The MySQL XA implementation is based on the X/Open CAE document Distributed Transaction Processing: The XA Specification. This document is published by The Open Group and available at
http://www.opengroup.org/public/pubs/catalog/c193.htm. Ref: XA Transactions