Method for determining a state associated with a transaction

A computer implemented method for determining a state associated with a transaction for use with a transactional processing system comprising a transaction coordinator and a plurality of grouped and inter-connected resource managers, the computer implemented method comprising:

• responsive to a communications failure between the transaction coordinator and a first resource manager causing a transaction to have an in-doubt state, connecting to a second resource manager;
• responsive to connecting, sending by the transaction coordinator to the second resource manager, a query requesting data associated with an in-doubt transaction;
• responsive to sending, collating, by the second resource manager, data associated with the in-doubt transaction associated with the second resource manager;
• determining a size associated with a subset of a first log associated with the first resource manager, and subsequently, obtaining at the first resource manager, by the second resource manager, a shared lock to data associated with the in-doubt transaction, wherein the obtaining further comprises obtaining a shared lock to the subset;
• and
• responsive to obtaining, collating, by the second resource manager, data associated with the in-doubt transaction associated with the first resource manager.

A hardware apparatus for determining a state associated with a transaction comprising a transaction coordinator and a plurality of grouped and inter-connected resource managers, the apparatus comprising:

• means, responsive to a communications failure between the transaction coordinator and a first resource manager causing a transaction to have an in-doubt state, for connecting to a second resource manager;
• means, responsive to the connection means, for causing the transaction coordinator to send to the second resource manager, a query requesting data associated with the in-doubt transaction;
• means for determining a size associated with a subset of a first log associated with the first resource manager;
• means for causing the second resource manager, subsequent to determining a size associated with a subset of a first log associated with the first resource manager, to obtain, at the first resource manager, a shared lock to data associated with the in-doubt transaction;
• and
• means, responsive to the obtaining means, for causing the second resource manager to collate data associated with the in-doubt transaction associated with the first resource manager;
• means, responsive to determining that the size has not changed for transmitting the data associated with the in-doubt transaction associated with the first resource manager to the transaction coordinator;
• and
• means, responsive to determining that the size has changed for re-obtaining a shared lock to the subset;
• means for collating, by the second resource manager, data associated with the in-doubt transaction associated with the first resource manager;
• and responsively, releasing the shared lock.