fix for bug CORE-4444 : Engine could hung and block all attachments in out of disk space condition during physical backup,
improvement CORE-4445 : Extend main database file faster when physical backup state changed from stalled to merge
2) Reworked the lock manager synchronization: added the RAII mutex holders and avoided dirty reads for the shared memory.
3) Encapsulated lck_length into the Lock class + small related refactoring.
4) Front ported recent fixes from the v2.x branches.
5) Misc cleanup.
Also some cleanups, the most important are:
- meaningful ctor on Jrd::Lock, helping to avoid code dup
- avoid unneeded h-file dependencies, making boot build engine dependent
1) Fixed CORE-1696 - "Deadlock in LM by using nbackup utility" with priority rating of lock requesting for LCK_backup_database and LCK_bdb.
2) A lot of stability fixes were made.
3) The key thing is using new GlobalRWLock for removing LCK_set_owner_handle function and speed up performance.
4) The code is still ready for using both in shared cache architecture and in claster architecture.
related with local events from isc_sync.cpp.
2. Cleanup - removed unused parameter 'number of events' from ISC_event_wait()
and two unused parameters from ISC_event_init().
3. Added SYSV-semaphore based implementation of IPC to isc_sync.cpp.
This should fix CORE-2102: Firebird 2.5 does not build on MacOS (Darwin).
4. Fixed use of posic CS without (x)inetd (i.e. fb_inet_server -s).
5. Fixed (to be reviewed by Dmitry) recovery after some process death in lock manager.
2. Fixed writing page while nbackup merge state is stalled.
3. Fixed using dead dbb in AST handler while somebody is changing cached lock of the GlobalRWLock.
