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
Problem:-
The condition that checks for node readiness is too strict as it does
not allow SELECTs even if these selects do not access any tables.
For example,if we run
SELECT 1;
OR
SELECT @@max_allowed_packet;
Solution:-
We need not to report this error when all_tables(lex->query_tables)
is NULL:
use get_current_user() to distinguish user name without
a hostname and a role name.
move privilege checks inside mysql_show_grants() to remove
duplicate get_current_user() calls
Fix remaining issues with wsrep_sync_wait and query cache.
- Fixes misplaced call to invalidate query cache in
Rows_log_event::do_apply_event().
Query cache was invalidated too early, and allowed old
entries to be inserted to the cache.
- Reset thd->wsrep_sync_wait_gtid on query cache hit.
THD->cleanup_after_query is not called in such cases,
and thd->wsrep_sync_wait_gtid remained initialized.
The admin commands in question are:
> OPTIMIZE
> REPAIR
> ANALYZE
For LOCAL or NO_WRITE_TO_BINLOG invocations of these commands, ie
OPTIMIZE LOCAL TABLE <t1>
they are not binlogged as expected.
Also, in addition, they are not executed under TOI.
Hence, they are not propagated to other nodes.
The effect is same as that of wsrep_on=0.
Also added tests for this.
A WSREP_DEBUG for wsrep_register_hton has also been added.
The galera_flush_local test has also been updated for verifying that effects
of NO_WRITE_TO_BINLOG / LOCAL are equivalent to wsrep_on=0 from wsrep
perspective.
(cherry picked from commit 5065122f94a8002d4da231528a46f8d9ddbffdc2)
Conflicts:
sql/sql_admin.cc
sql/sql_reload.cc
sql/wsrep_hton.cc
- Moves call wsrep_free_status() to THD::cleanup_after_query().
Wsrep status variables were previously freed only on SHOW STATUS.
- Removes valgrind suppression from mysql-test/valgrind.
- Added testing if connection is killed to shortcut reading of connection data
This will allow us later in 10.2 to do a cleaner shutdown of slaves (less errors in the log)
- Add new status variables: Slaves_connected, Slaves_running and Slave_connections.
- Use MYSQL_SLAVE_NOT_RUN instead of 0 with slave_running.
- Don't print obvious extra warnings to the error log when slave is shut down normally.
Problem is that FLUSH TABLES WITH READ LOCK first blocks threads from
starting new commits, then waits for running commits to complete. But
in-order parallel replication needs commits to happen in a particular
order, so this can easily deadlock.
To fix this problem, this patch introduces a way to temporarily pause
the parallel replication worker threads. Before starting FTWRL, we let
all worker threads complete in-progress transactions, and then
wait. Then we proceed to take the global read lock. Once the lock is
obtained, we unpause the worker threads. Now commits are blocked from
starting by the global read lock, so the deadlock will no longer occur.
EXPLAIN INSERT ... SELECT tried to use SELECT's execution path. This
caused a collection of problems:
- SELECT_DESCRIBE flag was not put into select_lex->options, which
means it was not in JOIN::select_options either (except for the first
member of the UNION).
- This caused UNION members to be executed. They would attempt to write
join output rows to the output.
- (Actual cause of the crash) second join sibling would call
result->send_eof() when finished execution. Then,
Explain_query::print_explain would attempt to write to query output
again, and cause an assertion due to non-empty query output.
[EXPLAIN] INSERT .. SELECT creates a select_insert object.
select_insert calls handler->start_bulk_insert() during
initialization.
For MyISAM/Aria this requires that a matching call to
handler->end_bulk_insert() call is made.
Regular INSERT .. SELECT accomplishes this by calling either
select_result->send_eof() or select_result->abort_result_set().
EXPLAIN INSERT ... SELECT didn't call either, which resulted in
improper de-initializaiton of handler object. Make it call
abort_result_set(), which invokes handler->end_bulk_insert().
Before this, FLUSH TABLES and FLUSH TABLES t1 (REFRESH_TABLES hereafter) were executed locally,
which also had implications for GTID. MySQL async replication does
replicate FLUSH TABLES.
Hence, this commit
a) Adds REFRESH_TABLES to TOI.
b) Skips LOCK-based REFRESH_TABLES from TOI, ie. FLUSH TABLES WITH READ
LOCK and FLUSH TABLES FOR EXPORT.
c) Executes them after reload_acl_and_cache. This is done since
reload_acl_and_cache checks for thd->locked_tables_mode and does upgrade
of MDL locks accordingly. A failure here means REFRESH_TABLES cannot
run.
i) This is also important since LOCK TABLES is not replicated in
galera.
d) Test galera_flush has been modified for
i) wsrep_replicate_myisam SESSION variable.
ii) Testing REFRESH_TABLES.
iii) Testing REFRESH_TABLES + LOCK TABLES.
e) Use different WSREP_TO_ISOLATION_BEGIN for global FLUSH TABLES and FLUSH TABLES <table,>.
