Test galera_sr_ddl_master would sometimes fail due to leftover
streaming replication fragments. Rollbacker thread would attempt to
open streaming_log table to remove the fragments, but would fail in
check_stack_overrun(). Ultimately the check_stack_overrun() failure
was caused by rollbacker missing to switch the victim's THD thread
stack to rollbacker's thread stack.
Also in this patch:
- Remove duplicate functionality in rollbacker helper functions,
and extract rollbacker fragment removal into function
wsrep_remove_streaming_fragments()
- Reuse open_for_write() in wsrep_schema::remove_fragments
- Partially revert changes to galera_sr_ddl_master test from
commit 44a11a7c08. Removed unnecessary
wait condition and isolation level setting
MariaDB 10.4 was crashing when thread-handling was set to
pool-of-threads and wsrep was enabled.
There were two apparent reasons for the crash:
- Connection handling in threadpool_common.cc was missing calls to
control wsrep client state.
- Thread specific storage which contains thread variables (THR_KEY_mysys)
was not handled appropriately by wsrep patch when pool-of-threads
was configured.
This patch addresses the above issues in the following way:
- Wsrep client state open/close was moved in thd_prepare_connection() and
end_connection() to have common handling for one-thread-per-connection
and pool-of-threads.
- Thread local storage handling in wsrep patch was reworked by introducing
set of wsrep_xxx_threadvars() calls which replace calls to
THD store_globals()/reset_globals() and deal with thread handling
specifics internally.
Wsrep-lib was updated to version which relaxes internal concurrency
related sanity checks.
Rollback code from wsrep_rollback_process() was extracted to separate calls
for better readability.
Post rollback thread was removed as it was completely unused.
* Collect and pass apply error data to provider
* Rollback failed transaction and continue operation if provider returns
SUCCESS
* MTR tests for inconsistency voting
- Note that some issues was also fixed in 10.2 and 10.4. I also fixed them
here to be able to continue with making 10.5 valgrind safe again
- Disable connection threads warnings when doing shutdown
Problem was that wsrep thread argument was deleted on wrong
place. Furthermore, scan method incorrectly used unsafe c_ptr().
Finally, fixed wsrep thread initialization to correctly set
up thread_id and pass correct argument to functions and
fix signess problem causing compiler errors.
Refactored wsrep patch to not use LOCK_thread_count and COND_thread_count anymore.
This has partially been replaced by using old LOCK_wsrep_slave_threads mutex.
For slave thread count change waiting, new COND_wsrep_slave_threads signal has been added
Added LOCK_wsrep_cluster_config mutex to control that cluster address change cannot happen in parallel
Protected wsrep_slave_threads variable changes with LOCK_cluster_config mutex
This is for avoiding concurrent slave thread count and cluster joining operations to happen
Fixes according to Teemu's review
* Removed all references related to wsrep_thd_pool (which was removed)
* Removed unused declarations in wsrep_schema.h
* The following would result invalid reads in
Wsrep_schema::replay_transaction():
```
frag_table->field[4]->val_str(&buf);
Wsrep_schema_impl::end_index_scan(frag_table);
Wsrep_schema_impl::finish_stmt(thd);
ret= wsrep_apply_events(thd, rli, buf.c_ptr_safe(), buf.length());
```
because `buf` was accessed after closing the table. The fix is to
perform storage reads using a different THD.
* In Wsrep_schema::recover_sr_transactions(), cluster_table was opened
for write, however it is only read here. And frag_table was opened
for read, wereas write is potentially needed.
Also, avoid copy caused by String::c_ptr() to zero terminate the c
string, use c_ptr_quick instead.
