Philip Martin <philip.mar...@wandisco.com> writes: > Stefan Fuhrmann <stefan.fuhrm...@wandisco.com> writes: > >> But we do write the database strictly in revision order. >> So, if we could simply read the latest record once upon >> opening the DB. If that refers to a future revision, read >> "current" and compare. If the DB it still "in the future", >> abort txn, i.e. prevent any future commit until rep-cache.db >> gets deleted by the admin. > > That might work. The rep-cache for a new revision is not written > strictly in revision order but is written after updating HEAD. So such > a check would not be as strong as "highest revision" but would be a > useful extra check if we can implement it efficiently it without a table > scan. Is sqlite3_last_insert_rowid() the function we want?
Bert pointed out that is the wrong function and there isn't really a suitable function. So to do this check we need something like Julian'ssuggestion: a one row table containing the most recent revision added to the rep-cache that gets updated with each write. It doesn't catch every possible failure but it does catch some. -- Philip Martin | Subversion Committer WANdisco // *Non-Stop Data*
