This was because of two issues:
- thr_multi_lock_after_thr_lock needed to be hit 3 times before go2 could
be signaled, because 2 of these happened before statistics_update_start
was reached.
- The original code didn't take into accunt that thr_locks can be executed in
any random order, which caused sporadic failures when waiting for 1 lock
of 3, as if the locks where in different order, there would be a dead-lock.
Fixed by introducing thr_multi_lock_before_thr_lock which is deterministic.
- Some of the test failures where not noticed as the DEBUG_SYNC timeout
would cause the test to pass (after 300 seconds).
Test results are distorted by a small rounding error
during an intermediate stage of calculating the result.
By using the SQL ROUND function we stablise tests.
Signed-off-by: Daniel Black <daniel.black@au.ibm.com>
The bug could cause a crash when several connections needed
persistent statistics for the same table.
Also added a missing call of set_statistics_for_table() in the code
of the function mysql_update.
If a query referenced some system statistical tables, but not all of them,
then executing an ANALYZE command simultaneously with this query could
lead to a deadlock.
The fix prohibited reading statistics from system statistical tables
for such queries.
Removed the function unlock_tables_n_open_system_tables_for_write()
as not used anymore.
Performed some minor refactoring of the code in sql_statistics.cc.
engine-independent statistics.
If a table was created for InnoDB then the execution of the
ANALYZE command over this table blocked any INSERT/DELETE/UPDATE
of the table.
table_stat -> table_stats
column_stat -> column_stats
index_stat -> index_stats
to be in line with the names of innodb statistical tables
from mysql-5.6: innodb_table_stats and innodb_index_stats.
Opening system statistical tables and reading statistical data from
them for a regular table should be done after opening and locking
this regular table.
No test case is provided with this patch.
