The transaction key, stored in the xactkey column of systransactions, acts as a unique internal handle to a server transaction. For local transactions, xactkey ensures that transactions can be distinguished from one another, even if the transaction name is not unique to the server.
Beginning with Adaptive Server version 12.0, all system tables refer to systransactions.xactkey to uniquely identify a transaction. The sysprocesses and syslogshold tables are the only exceptions to this rule—they reference systransactions.xactname and truncate the value to a length of varchar(64) (for sysprocesses) and varchar(67) (for syslogshold), to maintain backward compatibility with earlier Adaptive Server versions.
