MDEV-11227 - mysqlimport -l doesn't issue UNLOCK TABLES

Implementation of MDEV-7660 introduced unwanted incompatible change:
modifications under LOCK TABLES with autocommit enabled are rolled back on
disconnect. Previously everything was committed, because LOCK TABLES didn't
adjust autocommit setting.

This patch restores original behavior by reverting some changes done in
MDEV-7660:
- sql/sql_parse.cc: do not reset autocommit on LOCK TABLES
- sql/sql_base.cc: do not set autocommit on UNLOCK TABLES
- test cases: main.lock_tables_lost_commit, main.partition_explicit_prune,
  rpl.rpl_switch_stm_row_mixed, tokudb.nested_txn_implicit_commit,
  tokudb_bugs.db806

But it makes InnoDB tables under LOCK TABLES ... READ [LOCAL] not protected
against DML. To restore protection some changes from WL#6671 were merged,
specifically MDL_SHARED_READ_ONLY and test cases.

WL#6671 merge highlights:
- Not all tests merged.
- In MySQL LOCK TABLES ... READ acquires MDL_SHARED_READ_ONLY for all engines,
  in MariaDB MDL_SHARED_READ is always acquired first and then upgraded to
  MDL_SHARED_READ_ONLY for InnoDB only.
- The above allows us to omit MDL_SHARED_WRITE_LOW_PRIO implementation in
  MariaDB, which is rather useless with InnoDB. In MySQL it is needed to
  preserve locking behavior between low priority writes and LOCK TABLES ... READ
  for non-InnoDB engines (covered by sys_vars.sql_low_priority_updates_func).
- Omitted HA_NO_READ_LOCAL_LOCK, we rely on lock_count() instead.
- Omitted "piglets": in MariaDB stream of DML against InnoDB table may lead to
  concurrent LOCK TABLES ... READ starvation.
- HANDLER ... OPEN acquires MDL_SHARED_READ instead of MDL_SHARED in MariaDB.
- Omitted SNRW->X MDL lock upgrade for IMPORT/DISCARD TABLESPAECE under LOCK
  TABLES.
- Omitted strong locks for views, triggers and SP under LOCK TABLES.
- Omitted IX schema lock for LOCK TABLES READ.
- Omitted deadlock weight juggling for LOCK TABLES.

Full WL#6671 merge status:
- innodb.innodb-lock: fully merged
- main.alter_table: not merged due to different HANDLER solution
- main.debug_sync: fully merged
- main.handler_innodb: not merged due to different HANDLER solution
- main.handler_myisam: not merged due to different HANDLER solution
- main.innodb_mysql_lock: fully merged
- main.insert_notembedded: fully merged
- main.lock: not merged (due to no strong locks for views)
- main.lock_multi: not merged
- main.lock_sync: fully merged (partially in MDEV-7660)
- main.mdl_sync: not merged
- main.partition_debug_sync: not merged due to different HANDLER solution
- main.status: fully merged
- main.view: fully merged
- perfschema.mdl_func: not merged (no such test in MariaDB)
- perfschema.table_aggregate_global_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_global_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_global_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB)
- perfschema.table_lock_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB)
- sys_vars.sql_low_priority_updates_func: not merged
- include/thr_rwlock.h: not merged, rw_pr_lock_assert_write_owner and
  rw_pr_lock_assert_not_write_owner are macros in MariaDB
- sql/handler.h: not merged (HA_NO_READ_LOCAL_LOCK)
- sql/mdl.cc: partially merged (MDL_SHARED_READ_ONLY only)
- sql/mdl.h: partially merged (MDL_SHARED_READ_ONLY only)
- sql/lock.cc: fully merged
- sql/sp_head.cc: not merged
- sql/sp_head.h: not merged
- sql/sql_base.cc: partially merged (MDL_SHARED_READ_ONLY only)
- sql/sql_base.h: not merged
- sql/sql_class.cc: fully merged
- sql/sql_class.h: fully merged
- sql/sql_handler.cc: merged partially (different solution in MariaDB)
- sql/sql_parse.cc: partially merged, mostly omitted low priority write part
- sql/sql_reload.cc: not merged comment change
- sql/sql_table.cc: not merged SNRW->X upgrade for IMPORT/DISCARD TABLESPACE
- sql/sql_view.cc: not merged
- sql/sql_yacc.yy: not merged (MDL_SHARED_WRITE_LOW_PRIO, MDL_SHARED_READ_ONLY)
- sql/table.cc: not merged (MDL_SHARED_WRITE_LOW_PRIO)
- sql/table.h: not merged (MDL_SHARED_WRITE_LOW_PRIO)
- sql/trigger.cc: not merged
- storage/innobase/handler/ha_innodb.cc: merged store_lock()/lock_count()
  changes (in MDEV-7660), didn't merge HA_NO_READ_LOCAL_LOCK
- storage/innobase/handler/ha_innodb.h: fully merged in MDEV-7660
- storage/myisammrg/ha_myisammrg.cc: not merged comment change
- storage/perfschema/table_helper.cc: not merged (no MDL support in MariaDB PFS)
- unittest/gunit/mdl-t.cc: not merged
- unittest/gunit/mdl_sync-t.cc: not merged

MariaDB specific changes:
- handler.heap: different HANDLER solution, MDEV-7660
- handler.innodb: different HANDLER solution, MDEV-7660
- handler.interface: different HANDLER solution, MDEV-7660
- handler.myisam: different HANDLER solution, MDEV-7660
- main.mdl_sync: MDEV-7660 specific changes
- main.partition_debug_sync: removed test due to different HANDLER solution,
  MDEV-7660
- main.truncate_coverage: removed test due to different HANDLER solution,
  MDEV-7660
- mysql-test/include/mtr_warnings.sql: additional cleanup, MDEV-7660
- mysql-test/lib/v1/mtr_report.pl: additional cleanup, MDEV-7660
- plugin/metadata_lock_info/metadata_lock_info.cc: not in MySQL
- sql/sql_handler.cc: MariaDB specific fix for mysql_ha_read(), MDEV-7660

1 files changed, 96 insertions, 0 deletions

diff --git a/mysql-test/t/lock_sync.test b/mysql-test/t/lock_sync.test
index 07c16acc72a..af8435f7fbb 100644
--- a/mysql-test/t/lock_sync.test
+++ b/mysql-test/t/lock_sync.test
@@ -998,6 +998,102 @@ DROP TABLE t1;
 disconnect con1;
 disconnect con2;
 
+
+--echo #
+--echo # Bug#28587 SELECT is blocked by INSERT waiting on read lock, even with low_priority_updates
+--echo #
+set low_priority_updates=1;
+--disable_warnings
+drop table if exists t1;
+drop table if exists t2;
+--enable_warnings
+set debug_sync='RESET';
+create table t1 (a int, b int, unique key t1$a (a));
+create table t2 (j int, k int);
+set debug_sync='after_lock_tables_takes_lock SIGNAL parked WAIT_FOR go';
+--echo # Sending:
+--send insert into t2 select * from t1;
+connect (update,localhost,root,,);
+connection update;
+set debug_sync='now WAIT_FOR parked';
+set low_priority_updates=1;
+show variables like 'low_priority_updates';
+let $ID= `select connection_id()`;
+--send insert into t1 values (1, 2) ON DUPLICATE KEY UPDATE b = 2;
+connect (select,localhost,root,,);
+# we must wait till the insert opens and locks the table
+let $wait_condition=
+  select count(*) = 1 from information_schema.processlist
+  where state = "Waiting for table level lock" and id = $ID;
+--source include/wait_condition.inc
+select * from t1;
+set debug_sync='now SIGNAL go';
+connection default;
+disconnect update;
+disconnect select;
+--echo # Reaping INSERT SELECT
+--reap
+drop tables t1, t2;
+set low_priority_updates=default;
+set debug_sync='RESET';
+
+
+--echo #
+--echo # Additional test coverage for LOCK TABLES ... READ LOCAL
+--echo # for InnoDB tables.
+--echo #
+--echo # Check that we correctly handle deadlocks which can occur
+--echo # during metadata lock upgrade which happens when one tries
+--echo # to use LOCK TABLES ... READ LOCAL for InnoDB tables.
+
+--enable_connect_log
+CREATE TABLE t1 (i INT) ENGINE=InnoDB;
+CREATE TABLE t2 (j INT) ENGINE=InnoDB;
+
+--echo # Execute LOCK TABLE READ LOCK which will pause after acquiring
+--echo # SR metadata lock and before upgrading it to SRO lock.
+SET DEBUG_SYNC="after_open_table_mdl_shared SIGNAL locked WAIT_FOR go";
+--echo # Sending:
+--send LOCK TABLE t1 READ LOCAL
+
+connect (con1, localhost, root);
+SET DEBUG_SYNC="now WAIT_FOR locked";
+--echo # Execute RENAME TABLE which will try to acquire X lock.
+--echo # Sending:
+--send RENAME TABLE t1 TO t3, t2 TO t1, t3 TO t2
+
+connect (con2, localhost, root);
+--echo # Wait until RENAME TABLE is blocked.
+let $wait_condition=
+  select count(*) = 1 from information_schema.processlist
+  where state = "Waiting for table metadata lock" and
+        info = "RENAME TABLE t1 TO t3, t2 TO t1, t3 TO t2";
+--source include/wait_condition.inc
+--echo # Resume LOCK TABLE statement. It should try to
+--echo # upgrade SR lock to SRO lock which will create
+--echo # deadlock due to presence of pending X lock.
+--echo # Deadlock should be detected and LOCK TABLES should
+--echo # release its MDL and retry opening of tables.
+SET DEBUG_SYNC="now SIGNAL go";
+
+connection con1;
+--echo # RENAME TABLE should be able to complete. Reap it.
+--reap
+
+connection default;
+--echo # Reap LOCK TABLES.
+--reap
+--echo # Check that we see new version of table.
+SELECT * FROM t1;
+UNLOCK TABLES;
+
+--echo # Clean-up.
+SET DEBUG_SYNC="RESET";
+disconnect con1;
+disconnect con2;
+DROP TABLES t1, t2;
+--disable_connect_log
+
 # Check that all connections opened by test cases in this file are really
 # gone so execution of other tests won't be affected by their presence.
 --source include/wait_until_count_sessions.inc