> On March 26, 2014, 1:59 p.m., Chug Rolke wrote: > > The broker currently has a concept of a boot sequence number, which is > > incremented each time that qpidd restarts. This number is not the boot > > sequence number of the host computer. > > > > $ ./qpidd --log-enable debug+ > > ... debug ManagementAgent boot sequence: 44 > > > > $ ./qpidd --log-enable debug+ > > ... debug ManagementAgent boot sequence: 45 > > > > The exchange Message sequence number gets reset to zero at each qpidd > > restart. > > > > Trying to track each message sequence number through nonvolatile storage is > > a huge load. Also, it is likely that there are reliability problems > > tracking the sequence numbers through a broker crash or restart, just when > > the sequence numbers are critical. > > > > What about extending the concept of a "sequence number" to include "<broker > > boot sequence>:<exchange Message sequence number>"? > > > > These numbers exist today so there's no change to generate them. The new > > scheme would be a way to pack both numbers into a message instead of just > > the Message sequence number.
I like that idea. - Gordon ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/19566/#review38601 ----------------------------------------------------------- On March 23, 2014, 11:52 a.m., Pavel Moravec wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/19566/ > ----------------------------------------------------------- > > (Updated March 23, 2014, 11:52 a.m.) > > > Review request for qpid, Gordon Sim and Kim van der Riet. > > > Bugs: QPID-5642 > https://issues.apache.org/jira/browse/QPID-5642 > > > Repository: qpid > > > Description > ------- > > Elegant (but not performance optimal) way of patch: > > 1) In Exchange::PreRoute::PreRoute, update exchange in store (whole entry). > 2) The update method is dealed very similarly like > MessageStoreImpl::create(db_ptr db, IdSequence& seq, const > qpid::broker::Persistable& p) method, i.e. calls BufferValue that calls > Exchange::encode. > > Here the code can be unified by merging MessageStoreImpl::update > intoMessageStoreImpl::create method where the code almost duplicates. > > However I do not see the patch as performance efficient, as with every > message preroute, new qpid::framing::Buffer is filled in Exchange::encode > method, data are copied from it to char* BufferValue::data and even then they > are really written to the BDB. While in fact we just update the only one > number in the Buffer. > > I tried to come up with less performance invasive approach (for those > interested, see > https://bugzilla.redhat.com/attachment.cgi?id=877576&action=diff - if you > dont have access there, let me write), that keeps qpid::framing::Buffer for > every durable exchange with sequencing enabled, but it returned (among > others) into the need of changing the way store encodes/decodes Exchange > instance (change in Exchange::encode / decode methods). What would make the > broker backward incompatible. > > Is the performance penalty (due to Exchange::encode method called for every > message preroute) acceptable? > > Is it worth merging MessageStoreImpl::update intoMessageStoreImpl::create > method? > > > Diffs > ----- > > /trunk/qpid/cpp/src/qpid/broker/Exchange.cpp 1577475 > /trunk/qpid/cpp/src/qpid/broker/MessageStore.h 1577475 > /trunk/qpid/cpp/src/qpid/broker/MessageStoreModule.h 1577475 > /trunk/qpid/cpp/src/qpid/broker/MessageStoreModule.cpp 1577475 > /trunk/qpid/cpp/src/qpid/broker/NullMessageStore.h 1577475 > /trunk/qpid/cpp/src/qpid/broker/NullMessageStore.cpp 1577475 > /trunk/qpid/cpp/src/qpid/legacystore/MessageStoreImpl.h 1577475 > /trunk/qpid/cpp/src/qpid/legacystore/MessageStoreImpl.cpp 1577475 > /trunk/qpid/cpp/src/qpid/linearstore/MessageStoreImpl.h 1577475 > /trunk/qpid/cpp/src/qpid/linearstore/MessageStoreImpl.cpp 1577475 > /trunk/qpid/cpp/src/qpid/store/MessageStorePlugin.h 1577475 > /trunk/qpid/cpp/src/qpid/store/MessageStorePlugin.cpp 1577475 > > Diff: https://reviews.apache.org/r/19566/diff/ > > > Testing > ------- > > - reproducer from JIRA verified > - automated tests passed (except for those known to fail due to QPID-5641 > (valgrind & legacystore) > > > Thanks, > > Pavel Moravec > >
