A derby crash at exactly wrong time during a btree split can cause a corrupt db which can not be booted.
A problem in the split code and exact wrong timing of a crash can leave the database in as state
where undo of purge operations corrupts index pages during redo and can cause recovery boot
to never succeed and thus the database never to be booted. At hight level what happens is that
a purge happens on a page and before it commits another transactions uses the space of the
purge to do an insert and then commits, then the system crashes before the purging transactions
gets a chance to commit. During undo the purge expects there to be space to undo the purge
but there is not, and it corrupts the page in various ways depending on the size and placement
of the inserts. The error that actually returns to user varies from sane to insane as the problem
is actually noticed after the corruption occurs rather than during the undo.
- is related to
DERBY-5281 Derby DB Corrupt After Crash
DERBY-5248 Java Process Crash Causes Corrupt DB
- relates to
DERBY-5258 btree post commit releases latch before committing/aborting purges, possibly allowing other operation on page