Re: POC: Cleaning up orphaned files using undo logs

Hi All,

Please find the updated patch for the undo interface layer. I have
rebased undoprocessing patches on top of that and there are also some
changes in undo storage patch for handling the multi-log transaction
which I am attaching a separate patch for that
[0006-Defect-and-enhancement-in-multi-log-support.patch].

Mainly the new patch includes
1. Improvement in log-switch handling during recovery, earlier during
recovery we were detecting log switch by adding a separate WAL but in
this version, we are detecting it by the registered buffer in the WAL.
By doing this we are avoiding extra WAL plus this method is in more
sync with identifying undo log in UndoLogAllocateInRecovery.
2. Improved the mechanism of undo compression therein instead of
keeping the compression info in the global variable we are reading it
from the page in which we are inserting the undo record.
3. Improved readme file.

Apart from this, I have worked on the review comments posted in this
thread. I will reply to all those emails separately.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com