TP/XA

A global transaction is a distributed query where more than one database server is
involved in the query. A global transaction environment has the following parts:
    The client application
    The resource manager (IBM Informix database server)
    The transaction manager (vendor software

 

Loosely coupled mode means that the different database servers coordinate transactions, but do not share resources. The records from all branches of the transactions display as separate transactions in the logical log.
Tightly coupled mode means that the different database servers coordinate transactions and share resources such as locking and logging. The records from all branches of the transactions display as a single transaction in the logical log.

MTS tightly coupled transaction support has the following restrictions:
    Temporary tables are limited to one transaction branch. Different transaction branches within one global transaction cannot share a temporary table.
     Different transaction branches within one global transaction cannot share cursors.
     Different transaction branches within one global transaction cannot share an isolation level or lock-wait mode. The isolation level and lock-wait mode of each transaction branch must be set individually or set to the default level. If you want the same isolation level for all transaction branches, you must use SQL to specify this information for each transaction branch.

 

the H flag in the flags field identifies a heuristic rollback, 
the G flag identifies a global transaction, 
the L flag indicates loosely coupled mode, 
the T flag indicates tightly coupled mode

 

onmode -Z $address

onstat -x

onstat -G

onstat -z