9-58 IBM Informix OnLine Database Server Administrator’s Guide
Track a Transaction with tbstat Output
The default value of DEADLOCK_TIMEOUT is 60 seconds. Adjust this value
carefully. If you set it too low, individual OnLine database servers abort
transactions that are not deadlocks. If you set it too high, multiserver
deadlocks could reduce concurrency.

TXTIME-OUT

The configuration TXTIMEOUT is specific to IBMInformix STAR two-phase
commit protocol. It is only used if communication between a transaction
coordinator and participant has been interrupted and needs to be
reestablished.
The function ofTXTIMEOUT is to specify a period of time that a participant
OnLine waits to receive acommit instruction from a coordinator OnLine
during a distributed transaction. If the period of time specified by
TXTIMEOUT elapses, the participant OnLine checks the status of the trans-
action to determine if the participant should initiate automatic participant
recovery.
TXTIMEOUTis specified in seconds. The default value is 300 (five minutes).
The optimal value for this parameter varies, depending on your specific
environment and application. Before setting this parameter, read the
discussion that begins onpage 9-23.
Track a Transaction with tbstat Output
Themultiserver update capability supported by IBM Informix STAR requires
an enhancedtbstat -u output that can track both users and transactions. In
theIBM Informix STAR environment, relationships among users, transac-
tions, and locks (and other shared-memory resources) must be explicitly
described as follows:
Locks are owned by transactions, not by database server processes.
Transactions are usually owned by a database serverprocess.
A transaction can be orphaned and exist without being owned by a
database server process.
The transactions section of thetbstat -u output supports this level of
description. Each tbstat -u transactions field is explained in this section.