MDEV-14648 Restore fix for MySQL BUG#39053 - UNINSTALL PLUGIN does not allow...

MDEV-14648 Restore fix for MySQL BUG#39053 - UNINSTALL PLUGIN does not allow the storage engine to cleanup open connections

Also, allow the MariaDB 10.2 server to link InnoDB dynamically
against ha_innodb.so (which is what mysql-test-run.pl expects
to exist, instead of the default name ha_innobase.so).

wsrep_load_data_split(): Instead of referring to innodb_hton_ptr,
check the handlerton::db_type. This was recently broken by me in
MDEV-11415.

innodb_lock_schedule_algorithm: Define as a weak global symbol,
so that WITH_WSREP will not depend on InnoDB being linked statically.
I tested this manually. Notably, running a test that only does
	SET GLOBAL wsrep_on=1;
with a static or dynamic InnoDB and
	./mtr --mysqld=--loose-innodb-lock-schedule-algorithm=fcfs
will crash with SIGSEGV at shutdown. With the default VATS
combination the wsrep_on is properly refused for both the
static and dynamic InnoDB.

ha_close_connection(): Do invoke the method also for plugins
for which UNINSTALL PLUGIN was deferred due to open connections.
Thanks to @svoj for pointing this out.

thd_to_trx(): Return a pointer, not a reference to a pointer.

check_trx_exists(): Invoke thd_set_ha_data() for assigning a transaction.

log_write_checkpoint_info(): Remove an unused DEBUG_SYNC point
that would cause an assertion failure on shutdown after deferred
UNINSTALL PLUGIN.

This was tested as follows:

cmake -DWITH_WSREP=1 -DPLUGIN_INNOBASE:STRING=DYNAMIC \
-DWITH_MARIABACKUP:BOOL=OFF ...
make
cd mysql-test
./mtr innodb.innodb_uninstall

sql/handler.cc

 /* Copyright (c) 2000, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2016, MariaDB
+   Copyright (c) 2009, 2018, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -793,7 +793,9 @@ static my_bool closecon_handlerton(THD *thd, plugin_ref plugin,
 */
 void ha_close_connection(THD* thd)
 {
-  plugin_foreach(thd, closecon_handlerton, MYSQL_STORAGE_ENGINE_PLUGIN, 0);
+  plugin_foreach_with_mask(thd, closecon_handlerton,
+                           MYSQL_STORAGE_ENGINE_PLUGIN,
+                           PLUGIN_IS_DELETED|PLUGIN_IS_READY, 0);
 }
 
 static my_bool kill_handlerton(THD *thd, plugin_ref plugin,

sql/sql_load.cc

@@ -104,23 +104,25 @@ the transaction after every 10,000 inserted rows. */
 static bool wsrep_load_data_split(THD *thd, const TABLE *table,
 				  const COPY_INFO &info)
 {
-  extern struct handlerton* innodb_hton_ptr;
-
   DBUG_ENTER("wsrep_load_data_split");
 
-  if (wsrep_load_data_splitting && wsrep_on(thd)
-      && info.records && !(info.records % 10000)
-      && thd->transaction.stmt.ha_list
-      && thd->transaction.stmt.ha_list->ht() == binlog_hton
-      && thd->transaction.stmt.ha_list->next()
-      && thd->transaction.stmt.ha_list->next()->ht() == innodb_hton_ptr
-      && !thd->transaction.stmt.ha_list->next()->next())
+  if (!wsrep_load_data_splitting || !wsrep_on(thd)
+      || !info.records || (info.records % 10000)
+      || !thd->transaction.stmt.ha_list
+      || thd->transaction.stmt.ha_list->ht() != binlog_hton
+      || !thd->transaction.stmt.ha_list->next()
+      || thd->transaction.stmt.ha_list->next()->next())
+    DBUG_RETURN(false);
+
+  if (handlerton* hton= thd->transaction.stmt.ha_list->next()->ht())
   {
+    if (hton->db_type != DB_TYPE_INNODB)
+      DBUG_RETURN(false);
     WSREP_DEBUG("intermediate transaction commit in LOAD DATA");
     if (wsrep_run_wsrep_commit(thd, true) != WSREP_TRX_OK) DBUG_RETURN(true);
     if (binlog_hton->commit(binlog_hton, thd, true)) DBUG_RETURN(true);
     wsrep_post_commit(thd, true);
-    innodb_hton_ptr->commit(innodb_hton_ptr, thd, true);
+    hton->commit(hton, thd, true);
     table->file->extra(HA_EXTRA_FAKE_START_STMT);
   }
 

sql/wsrep_var.cc

@@ -42,7 +42,10 @@ int wsrep_init_vars()
   return 0;
 }
 
-extern ulong innodb_lock_schedule_algorithm;
+/* This is intentionally declared as a weak global symbol, so that
+linking will succeed even if the server is built with a dynamically
+linked InnoDB. */
+ulong innodb_lock_schedule_algorithm __attribute__((weak));
 
 bool wsrep_on_update (sys_var *self, THD* thd, enum_var_type var_type)
 {

storage/innobase/CMakeLists.txt

@@ -151,6 +151,7 @@ SET(INNOBASE_SOURCES
 	ut/ut0timer.cc)
 
 MYSQL_ADD_PLUGIN(innobase ${INNOBASE_SOURCES} STORAGE_ENGINE
+  MODULE_OUTPUT_NAME ha_innodb
   DEFAULT RECOMPILE_FOR_EMBEDDED
   LINK_LIBRARIES
 	${ZLIB_LIBRARY}

storage/innobase/handler/ha_innodb.cc

@@ -154,12 +154,9 @@ innodb_check_deprecated(void);
 
 #ifdef WITH_WSREP
 #include "dict0priv.h"
-#include "../storage/innobase/include/ut0byte.h"
+#include "ut0byte.h"
 #include <mysql/service_md5.h>
 
-class  binlog_trx_data;
-extern handlerton *binlog_hton;
-
 extern MYSQL_PLUGIN_IMPORT MYSQL_BIN_LOG mysql_bin_log;
 
 static inline wsrep_ws_handle_t*
@@ -1961,14 +1958,11 @@ thd_innodb_tmpdir(
 }
 
 /** Obtain the InnoDB transaction of a MySQL thread.
-@param[in,out]	thd	MySQL thread handler.
+@param[in,out]	thd	thread handle
 @return reference to transaction pointer */
-MY_ATTRIBUTE((warn_unused_result))
-trx_t*&
-thd_to_trx(
-	THD*	thd)
+static trx_t* thd_to_trx(THD* thd)
 {
-	return(*(trx_t**) thd_ha_data(thd, innodb_hton_ptr));
+	return *reinterpret_cast<trx_t**>(thd_ha_data(thd, innodb_hton_ptr));
 }
 
 #ifdef WITH_WSREP
@@ -2877,20 +2871,19 @@ check_trx_exists(
 /*=============*/
 	THD*	thd)	/*!< in: user thread handle */
 {
-	trx_t*&	trx = thd_to_trx(thd);
-
-	if (trx == NULL) {
+	if (trx_t* trx = thd_to_trx(thd)) {
+		ut_a(trx->magic_n == TRX_MAGIC_N);
+		innobase_trx_init(thd, trx);
+		return trx;
+	} else {
 		trx = innobase_trx_allocate(thd);
 		/* User trx can be forced to rollback,
 		so we unset the disable flag. */
 		ut_ad(trx->in_innodb & TRX_FORCE_ROLLBACK_DISABLE);
 		trx->in_innodb &= TRX_FORCE_ROLLBACK_MASK;
-	} else {
-		ut_a(trx->magic_n == TRX_MAGIC_N);
-		innobase_trx_init(thd, trx);
+		thd_set_ha_data(thd, innodb_hton_ptr, trx);
+		return trx;
 	}
-
-	return(trx);
 }
 
 /*************************************************************************
@@ -2900,8 +2893,7 @@ innobase_get_trx()
 {
 	THD *thd=current_thd;
 	if (likely(thd != 0)) {
-		trx_t*& trx = thd_to_trx(thd);
-		return(trx);
+		return thd_to_trx(thd);
 	} else {
 		return(NULL);
 	}

storage/innobase/handler/ha_innodb.h

 /*****************************************************************************
 
 Copyright (c) 2000, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2017, MariaDB Corporation.
+Copyright (c) 2013, 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -911,11 +911,6 @@ innodb_base_col_setup_for_stored(
 	create_table_info_t::normalize_table_name_low(norm_name, name, FALSE)
 #endif /* _WIN32 */
 
-/** Obtain the InnoDB transaction of a MySQL thread.
-@param[in,out]	thd	MySQL thread handler.
-@return reference to transaction pointer */
-trx_t*& thd_to_trx(THD*	thd);
-
 /** Converts an InnoDB error code to a MySQL error code.
 Also tells to MySQL about a possible transaction rollback inside InnoDB caused
 by a lock wait timeout or a deadlock.

storage/innobase/lock/lock0lock.cc

@@ -54,7 +54,7 @@ Created 5/7/1996 Heikki Tuuri
 #endif /* WITH_WSREP */
 
 /** Lock scheduling algorithm */
-ulong innodb_lock_schedule_algorithm = INNODB_LOCK_SCHEDULE_ALGORITHM_FCFS;
+ulong innodb_lock_schedule_algorithm;
 
 /** The value of innodb_deadlock_detect */
 my_bool	innobase_deadlock_detect;

storage/innobase/log/log0log.cc

@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2014, 2017, MariaDB Corporation.
+Copyright (c) 2014, 2018, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -1584,8 +1584,6 @@ log_write_checkpoint_info(bool sync, lsn_t end_lsn)
 		rw_lock_s_lock(&log_sys->checkpoint_lock);
 		rw_lock_s_unlock(&log_sys->checkpoint_lock);
 
-		DEBUG_SYNC_C("checkpoint_completed");
-
 		DBUG_EXECUTE_IF(
 			"crash_after_checkpoint",
 			DBUG_SUICIDE(););