crash of MariaDB/Galera
mysqld crashes during startup when its started with --wsrep-recover
(mysqld_safe.sh). The problem was that during server startup "wsrep"
handle is not initialized for --wsrep-recover and since the condition
to register wsrep hton depended only on 'wsrep_on' global/session
variables (WSREP(thd) macro), it can eventually get registered and
calls to wsrep handle's functions (commit, rollback, etc.) can be
made (SIGSEGV!).
Fixed by adding a check for "wsrep" pointer in WSREP(thd) macro
(added by lp:1367173). Additionally, a check for WSREP(thd)
(instead of checking the availability of wsrep provider) has been
added before invoking wsrep handle's commit & rollback functions.
Merged lp:maria/maria-10.0-galera up to revision 3879.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
This is now otherwise on level wsrep-25.9, but storage/innobase has not been fully merged
wsrep-5.5 is not good source for that, so we probably have to cherry pick innodb changes from wsrep-5.6
