Modified the bug fix for MDEV-36554 by replacing the general

mechanishm for disabling assertions in InnoDB code with solution
specific to this rollback issue.

The appliers sets a flag in the applier thread for the duration of the
local rollback. This is used in InnoDB code to detect a local
rollback.

Author: plampio

include/mysql/service_wsrep.h

@@ -69,6 +69,7 @@ extern struct wsrep_service_st {
   bool                        (*wsrep_thd_ignore_table_func)(MYSQL_THD thd);
   long long                   (*wsrep_thd_trx_seqno_func)(const MYSQL_THD thd);
   my_bool                     (*wsrep_thd_is_aborting_func)(const MYSQL_THD thd);
+  my_bool                     (*wsrep_thd_in_rollback_func)(const THD *thd);
   void                        (*wsrep_set_data_home_dir_func)(const char *data_dir);
   my_bool                     (*wsrep_thd_is_BF_func)(const MYSQL_THD thd, my_bool sync);
   my_bool                     (*wsrep_thd_is_local_func)(const MYSQL_THD thd);
@@ -128,6 +129,7 @@ extern struct wsrep_service_st {
 #define wsrep_set_data_home_dir(A) wsrep_service->wsrep_set_data_home_dir_func(A)
 #define wsrep_thd_is_BF(T,S) wsrep_service->wsrep_thd_is_BF_func(T,S)
 #define wsrep_thd_is_aborting(T) wsrep_service->wsrep_thd_is_aborting_func(T)
+#define wsrep_thd_in_rollback_func(T) wsrep_service->wsrep_thd_in_rollback_func(T)
 #define wsrep_thd_is_local(T) wsrep_service->wsrep_thd_is_local_func(T)
 #define wsrep_thd_self_abort(T) wsrep_service->wsrep_thd_self_abort_func(T)
 #define wsrep_thd_append_key(T,W,N,K) wsrep_service->wsrep_thd_append_key_func(T,W,N,K)
@@ -230,6 +232,8 @@ extern "C" my_bool wsrep_thd_order_before(const MYSQL_THD left, const MYSQL_THD
 extern "C" my_bool wsrep_thd_skip_locking(const MYSQL_THD thd);
 /* Return true if thd is aborting */
 extern "C" my_bool wsrep_thd_is_aborting(const MYSQL_THD thd);
+/* Return true if thd is a WSREP applier rolling back a transaction locally */
+extern "C" my_bool wsrep_thd_in_rollback(const MYSQL_THD thd);
 
 struct wsrep_key;
 struct wsrep_key_array;

sql/service_wsrep.cc

@@ -295,6 +295,22 @@ extern "C" my_bool wsrep_thd_is_aborting(const MYSQL_THD thd)
   return false;
 }
 
+/** Check if a wsrep applier is rolling back a transaction locally.
+
+This function is used for notifying InnoDB routines that this thread
+is rolling back a wsrep transaction locally.
+
+@param thd         thread handle
+
+@return true       if wsrep applier is rolling back a transaction locally
+@return false      otherwise
+
+*/
+extern "C" my_bool wsrep_thd_in_rollback(const THD *thd)
+{
+  return thd->wsrep_applier_is_in_rollback();
+}
+
 static inline enum wsrep::key::type
 map_key_type(enum Wsrep_service_key_type type)
 {

sql/sql_class.cc

@@ -742,6 +742,7 @@ THD::THD(my_thread_id id, bool is_wsrep_applier)
    ,
    wsrep_applier(is_wsrep_applier),
    wsrep_applier_closing(false),
+   wsrep_applier_in_rollback(false),
    wsrep_client_thread(false),
    wsrep_retry_counter(0),
    wsrep_PA_safe(true),
@@ -762,7 +763,6 @@ THD::THD(my_thread_id id, bool is_wsrep_applier)
    wsrep_affected_rows(0),
    wsrep_has_ignored_error(false),
    wsrep_was_on(false),
-   wsrep_assert_bitmask(0),
    wsrep_ignore_table(false),
    wsrep_aborter(0),
    wsrep_delayed_BF_abort(false),
@@ -8660,20 +8660,3 @@ LEX_CSTRING make_string(THD *thd, const char *start_ptr,
   size_t length= end_ptr - start_ptr;
   return {strmake_root(thd->mem_root, start_ptr, length), length};
 }
-
-
-#ifdef WITH_WSREP
-void wsrep_set_assert(THD *thd, uint64 assert, bool is_disabled)
-{
-  if (is_disabled) {
-    thd->wsrep_assert_bitmask |= assert;
-  } else {
-    thd->wsrep_assert_bitmask &= ~assert;
-  }
-}
-
-bool wsrep_get_assert(THD *thd, uint64 assert)
-{
-  return (thd->wsrep_assert_bitmask & assert ? true: false);
-}
-#endif /* WITH_WSREP */

sql/sql_class.h

@@ -5641,6 +5641,8 @@ class THD: public THD_count, /* this must be first */
 #ifdef WITH_WSREP
   bool                      wsrep_applier; /* dedicated slave applier thread */
   bool                      wsrep_applier_closing; /* applier marked to close */
+  bool                      wsrep_applier_in_rollback; /* applier is rolling
+                                                          back a transaction */
   bool                      wsrep_client_thread; /* to identify client threads*/
   query_id_t                wsrep_last_query_id;
   XID                       wsrep_xid;
@@ -5682,7 +5684,6 @@ class THD: public THD_count, /* this must be first */
   bool                      wsrep_has_ignored_error;
   /* true if wsrep_on was ON in last wsrep_on_update */
   bool                      wsrep_was_on;
-  uint64                    wsrep_assert_bitmask;
 
   /*
     When enabled, do not replicate/binlog updates from the current table that's
@@ -5760,6 +5761,8 @@ class THD: public THD_count, /* this must be first */
   Wsrep_applier_service* wsrep_applier_service;
   /* wait_for_commit struct for binlog group commit */
   wait_for_commit wsrep_wfc;
+  bool wsrep_applier_is_in_rollback() const
+  { return wsrep_applier_in_rollback; }
 #endif /* WITH_WSREP */
 
   /* Handling of timeouts for commands */
@@ -8522,11 +8525,5 @@ LEX_CSTRING make_string(THD *thd, const char *start_ptr,
 
 #include "deprecation.h"
 
-
-#ifdef WITH_WSREP
-extern void wsrep_set_assert(THD* thd, uint64 assert, bool is_disabled);
-extern bool wsrep_get_assert(THD* thd, uint64 assert);
-#endif
-
 #endif /* MYSQL_SERVER */
 #endif /* SQL_CLASS_INCLUDED */

sql/sql_plugin_services.inl

@@ -159,6 +159,7 @@ static struct wsrep_service_st wsrep_handler = {
   wsrep_thd_ignore_table,
   wsrep_thd_trx_seqno,
   wsrep_thd_is_aborting,
+  wsrep_thd_in_rollback,
   wsrep_set_data_home_dir,
   wsrep_thd_is_BF,
   wsrep_thd_is_local,

sql/wsrep_applier.cc

@@ -292,14 +292,14 @@ int wsrep_apply_events(THD*                       thd,
 
     /* rollback to savepoint without telling Wsrep-lib */
     thd->variables.wsrep_on = false;
-    wsrep_set_assert(thd, true, WSREP_ASSERT_INNODB_TRX);
+    thd->wsrep_applier_in_rollback= true;
     if (FALSE != trans_rollback_to_savepoint(thd, savepoint)) {
       thd->variables.wsrep_on = true;
-      wsrep_set_assert(thd, false, WSREP_ASSERT_INNODB_TRX);
+      thd->wsrep_applier_in_rollback= false;
       break;
     }
     thd->variables.wsrep_on = true;
-    wsrep_set_assert(thd, false, WSREP_ASSERT_INNODB_TRX);
+    thd->wsrep_applier_in_rollback= false;
 
     /* reset THD object for retry */
     thd->clear_error();

sql/wsrep_dummy.cc

@@ -94,6 +94,9 @@ long long wsrep_thd_trx_seqno(const THD *)
 my_bool wsrep_thd_is_aborting(const THD *)
 { return 0; }
 
+my_bool wsrep_thd_in_rollback(const THD *)
+{ return 0; }
+
 void wsrep_set_data_home_dir(const char *)
 { }
 

storage/innobase/trx/trx0trx.cc

@@ -1382,10 +1382,6 @@ ATTRIBUTE_NOINLINE static void trx_commit_cleanup(trx_undo_t *&undo)
   undo= nullptr;
 }
 
-
-extern bool wsrep_get_assert(THD *thd, uint64 assert);
-
-
 TRANSACTIONAL_INLINE inline void trx_t::commit_in_memory(const mtr_t *mtr)
 {
   /* We already detached from rseg in write_serialisation_history() */
@@ -1505,9 +1501,11 @@ TRANSACTIONAL_INLINE inline void trx_t::commit_in_memory(const mtr_t *mtr)
     trx_finalize_for_fts(this, undo_no != 0);
 
 #ifdef WITH_WSREP
-  if (!mysql_thd || !wsrep_get_assert(mysql_thd, WSREP_ASSERT_INNODB_TRX)) {
-    ut_ad(is_wsrep() == wsrep_on(mysql_thd));
-  }
+  /* Assert that any transaction which is started as a wsrep
+     transaction, also commits or rolls back as a wsrep
+     transaction. Wsrep applier may turn wsrep off temporarily for
+     rollback when the applying of wsrep transactions is retried. */
+  ut_ad(is_wsrep() == wsrep_on(mysql_thd) || wsrep_thd_in_rollback(mysql_thd));
 
   /* Serialization history has been written and the transaction is
   committed in memory, which makes this commit ordered. Release commit