On Wed, Oct 14, 2015 at 9:31 AM, Kiran Ayyagari <[email protected]> wrote:
> > > On Wed, Oct 14, 2015 at 9:13 PM, Emmanuel Lécharny <[email protected]> > wrote: > >> Hi guys, >> >> so we have clear case where the JDBM backend get corrupted, up to a >> point a full reimport of the data is required. Lucas also proved that a >> test will fail, after haing injected 1000 entries and doing 100 rename >> (https://issues.apache.org/jira/browse/DIRSERVER-1974). >> >> This is more than annoying... >> >> I have tested DIRSERVER-1974 with Mavibot, and I can't reproduce the >> problem, which means the server is safe. The resulting database is 14 Mb >> big with the 1000 entries being added, which is big, but acceptable. >> >> At this point, I wonder if it would not be a safe approach to switch to >> Mavibot right now ? >> >> The pros : >> - we know that we can't have a database corruption, because each update >> is a new revision >> - technically, mavibot is faster than JDBM >> - we aren't maintaining JDBM, while Mavibot is under development >> >> The cons : >> - Mavibot is still under developement : we still have to add teh >> cross-btree transactions, which means that if we have a brutal crash >> during an update, then we may have some inconsistancy in the base >> (inconsitancy != corruption, but still) >> - We will still need the global write locking strategy to protect the >> backend from concurrent reads and write when a update is processed >> - The database is growing fast due to the limited cleanup we currently do >> >> However, in the middle term, Mavibot will bring the following bonuses : >> - cross btree transaction support (actually, we may even support >> multiple updates within a single transaction, speeding up the update >> even more), which will allow us to remove the global RW lock we >> currently have >> - bulkloading capacity, increasing teh speed of injecting data by at >> leats 2 orders of magnitude (server being stopped) >> >> >> So, I'll ask you : what about releasing M21 with Mavibot as a default, >> but with a possibility for users to still pick JDBM on demand ? >> >> I am in favor of that, I have tested it with the server few months ago > after > adding free page reclaiming functionality and it was _working_ > > The addition of entries gets slower after a point of time, but other than > that > I have not seen any other issues, this is just from one user pov though. > > Server needs to modify a bit to detect the type of storage used in an > existing partition > and initialize accordingly. > > -- > Kiran Ayyagari > http://keydap.com > I agree, I think it is time we migrate to Mavibot unless there is some major stumbling block and I think you two are probably the only 2 people who could speak to that. So if you are comfortable with the transition, I'm all for it. Lucas.
