Problem: SELECTs prohibited for a transactional SE in autocommit mode
if read_only is set.
Fix: allow them.
mysql-test/r/read_only_innodb.result:
Fix for bug #35732: read-only blocks SELECT statements in InnoDB
- test result.
mysql-test/t/read_only_innodb.test:
Fix for bug #35732: read-only blocks SELECT statements in InnoDB
- test case.
sql/handler.cc:
Fix for bug #35732: read-only blocks SELECT statements in InnoDB
- in autocommit mode thd->transaction.all list is empty thus
is_real_trans set to TRUE for any SELECTs, so using it in the
"read_only" check is insufficient.
ha_check_and_coalesce_trx_read_only() changed to return number
of engines with read-write changes. This value is used in the
"read-only" check and checks for GLOBAL READ LOCK.
sql/lock.cc:
Fix for bug #35732: read-only blocks SELECT statements in InnoDB
- added assert(protect_against_global_read_lock) before decreasing,
in order to catch (uint) 0 - 1 situation due to wrong
wait_if_global_read_lock()/start_waiting_global_read_lock() call
sequence.
Bug#11733 (COMMITs should not happen if read-only is set)
Bug#22009 (Can write to a read-only server under some circumstances)
See the work log for details
The change consist of
a) acquiring the global read lock in SET GLOBAL READONLY
b) honoring opt_readonly in ha_commit_trans(),
c) honoring opt_readonly in mysql_lock_tables().
a) takes care of the server stability,
b) makes the transactional tables safe (Bug 11733)
c) makes the non transactional tables safe (Bug 22009)
mysql-test/r/read_only.result:
WL#3602 (SET GLOBAL READONLY)
mysql-test/t/read_only.test:
WL#3602 (SET GLOBAL READONLY)
sql/handler.cc:
WL#3602 (SET GLOBAL READONLY)
sql/lock.cc:
WL#3602 (SET GLOBAL READONLY)
sql/set_var.cc:
WL#3602 (SET GLOBAL READONLY)
sql/set_var.h:
WL#3602 (SET GLOBAL READONLY)
mysql-test/r/read_only_innodb.result:
WL#3602 (SET GLOBAL READONLY)
mysql-test/t/read_only_innodb.test:
WL#3602 (SET GLOBAL READONLY)
