Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
In galera cluster, the definer (and thus binlog invoker) must be set
for CREATE ROLE before Query_log_event is created during TOI on the
originating node.
- changed the condition when to do implicit desync as part of FTWRL to
cover only case when node is PC and synced. Donor node has alreaydy desycned
and other states mean that node is not in cluster, so desync is not even possible.
- reverted from tracking donor servicing thread. With xtrabackup SST,
xtrabackup thread will call FTWRL and node is desynced upfront
- Skipping desync in FTWRL if node is operating as donor
- Fixes query cache so that it is aware of wsrep_sync_wait.
Query cache would return (possibly stale) results to the
client, regardless of the value of wsrep_sync_wait.
- Includes the test case that reproduced the issue.
Problem:
When mysqld starts as a galera node, it creates 2 system threads
(applier & rollbacker) using start_wsrep_THD(). These threads are
created before plugin initialization (plugin_init()) for SST methods
like rsync and xtrabackup.
The threads' initialization itself can proceed in parallel to mysqld's
main thread of execution. As a result, the thread initialization code
(start_wsrep_THD()) can end up accessing some un/partially initialized
structures (like maria_hton, in this particular case) resulting in
segfault.
Solution:
Fixed by calling THD::init_for_queries() (which accesses maria_hton)
only after the plugins have been initialized.
(Additional fix in 10.0-galera branch)
THD's lex->definer initially holds "*current_user" for
CURRENT_USER(). Use get_current_user() to get the real
current user.
In galera, like other DDLs, CREATE/ALTER VIEW commands are recreated
and replicated during parsing. The ALGORITHM clause is internally set
to VIEW_ALGORITHM_INHERIT if its not explicitly specified by the user.
But since its not a valid type to be used in a command, it leads to an
assertion failure. The solution is to not include the ALGORITHM clause
in the command if its not explicitly specified (or INHERIT).
* Wait for aborted thd (victim) to release MDL locks
* Skip aborting an already aborted thd
* Defer setting OK status in case of CTAS
* Minor cosmetic changes
* Added a test case
1. factored XID-related functions to a separate wsrep_xid.cc unit.
2. refactored them to take refrences instead of pointers where appropriate
3. implemented wsrep_get/set_SE_position to take wsrep_uuid_t and wsrep_seqno_t instead of XID
4. call wsrep_set_SE_position() in wsrep_sst_received() to reinitialize SE checkpoint after SST was received, avoid assert() in setting code by first checking current position.
