Sorry, that was "construct graph" (as a form of TDB output), not "map". Still new to this.
On Tue, Mar 27, 2012 at 12:38 PM, Bernie Greenberg <[email protected]>wrote: > I don't know (businesswise) if I can post my stack trace or details of my > code, but, first of all, my coworker was testing the code I had modified; > he didn't write any new code, he just operated its UI correctly. > > One thread was in "begin(WRITE); make model; add assertions; commit; > end()" on the dataset, and the other attempted to" begin(READ); construct > map; end()," but instead of waiting in begin(READ), caused the thread with > the write-lock to crash. The cited URL addresses a type of abuse of which > I wouldn't dream, if I understand it correctly (one thread exploiting > another's ownership of the database). I would expect that, with no further > code, a thread doing a begin(READ) should wait for a thread that > successfully executed begin(WRITE) to exit from end() before the > begin(READ) returns to its caller; is this not so? > > If you truly need more stack trace, I'll see what I can do. > > Bernie > > > On Mon, Mar 26, 2012 at 4:40 PM, Andy Seaborne <[email protected]> wrote: > >> On 26/03/12 16:13, Bernie Greenberg wrote: >> >>> The new transaction primitives worked superlatively for me, but not for >>> my >>> coworker testing my code. As soon as he issued a query while updates >>> were >>> going on, the latter crashed. mid-transaction. >>> >>> Does dataset.begin/dataset.end provide, in addition to transaction >>> safety, >>> thread synchronization/locking as well (as I imagine(d)), or must I wrap >>> Jena critical sections around each such pair if that is what I expect? >>> (In >>> either case, the doc for begin/end should say). >>> >>> Thanks, >>> Bernie >>> >>> >> Bernie, >> >> Do you have a test case or details of the crash? >> >> Within a transaction all access must be multi-reader or single-writer. >> The normal pattern is one thread, one transaction. >> >> http://incubator.apache.org/**jena/documentation/tdb/tdb_** >> transactions.html#multi-**threaded_use<http://incubator.apache.org/jena/documentation/tdb/tdb_transactions.html#multi-threaded_use> >> >> How is your coworker's testign using the transaction mechanism? >> >> Andy >> > >
