don't copy stmt IO_CACHE to trx IO_CACHE at the stmt end

instead use only one (trx) IO_CACHE and truncate it if the
statement is rolled back.

don't use binlog_cache_mngr to accumulate the data,
use binlog_cache_data instead.

(binlog_cache_data owns one IO_CACHE, binlog_cache_mngr owns
two binlog_cache_data's, trx and stmt).

sql/handler.cc

@@ -7255,18 +7255,13 @@ bool handler::check_table_binlog_row_based_internal()
 static int binlog_log_row_online_alter(TABLE* table,
                                        const uchar *before_record,
                                        const uchar *after_record,
-                                       Log_func *log_func,
-                                       bool has_trans)
+                                       Log_func *log_func)
 {
   THD *thd= table->in_use;
 
   if (!table->online_alter_cache)
   {
-    auto *cache_mngr= online_alter_binlog_get_cache_mngr(thd, table);
-    // Use transaction cache directly, if it is not multi-transaction mode
-    table->online_alter_cache= binlog_get_cache_data(cache_mngr,
-                                        !thd->in_multi_stmt_transaction_mode());
-
+    table->online_alter_cache= online_alter_binlog_get_cache_data(thd, table);
     trans_register_ha(thd, false, binlog_hton, 0);
     if (thd->in_multi_stmt_transaction_mode())
       trans_register_ha(thd, true, binlog_hton, 0);
@@ -7278,7 +7273,7 @@ static int binlog_log_row_online_alter(TABLE* table,
   table->rpl_write_set= &table->s->all_set;
 
   int error= (*log_func)(thd, table, table->s->online_alter_binlog,
-                         table->online_alter_cache, has_trans,
+                         table->online_alter_cache, true,
                          before_record, after_record);
 
   table->rpl_write_set= old_rpl_write_set;
@@ -7337,7 +7332,7 @@ int handler::binlog_log_row(const uchar *before_record,
 #ifdef HAVE_REPLICATION
   if (unlikely(!error && table->s->online_alter_binlog))
     error= binlog_log_row_online_alter(table, before_record, after_record,
-                                       log_func, row_logging_has_trans);
+                                       log_func);
 #endif // HAVE_REPLICATION
 
   DBUG_RETURN(error);

sql/log.cc

@@ -276,10 +276,10 @@ void make_default_log_name(char **out, const char* log_ext, bool once)
   Helper classes to store non-transactional and transactional data
   before copying it to the binary log.
 */
-class binlog_cache_data
+class binlog_cache_data: public ilist_node<>
 {
 public:
-  binlog_cache_data(): m_pending(0), status(0),
+  binlog_cache_data(): share(0), m_pending(0), status(0),
   before_stmt_pos(MY_OFF_T_UNDEF),
   incident(FALSE),
   saved_max_binlog_cache_size(0), ptr_binlog_cache_use(0),
@@ -362,6 +362,11 @@ class binlog_cache_data
      before_stmt_pos= pos;
   }
   
+  void store_prev_position()
+  {
+    before_stmt_pos= my_b_write_tell(&cache_log);
+  }
+
   void restore_prev_position()
   {
     truncate(before_stmt_pos);
@@ -414,6 +419,7 @@ class binlog_cache_data
   */
   IO_CACHE cache_log;
 
+  TABLE_SHARE *share; // for online alter table
 private:
   /*
     Pending binrows event. This event is the event where the rows are currently
@@ -512,16 +518,15 @@ void Log_event_writer::set_incident()
 }
 
 
-class binlog_cache_mngr: public ilist_node<> {
+class binlog_cache_mngr {
 public:
   binlog_cache_mngr(my_off_t param_max_binlog_stmt_cache_size,
                     my_off_t param_max_binlog_cache_size,
                     ulong *param_ptr_binlog_stmt_cache_use,
                     ulong *param_ptr_binlog_stmt_cache_disk_use,
                     ulong *param_ptr_binlog_cache_use,
-                    ulong *param_ptr_binlog_cache_disk_use,
-                    TABLE_SHARE *share)
-    : last_commit_pos_offset(0), using_xa(FALSE), xa_xid(0), share(share)
+                    ulong *param_ptr_binlog_cache_disk_use)
+    : last_commit_pos_offset(0), using_xa(FALSE), xa_xid(0)
   {
      stmt_cache.set_binlog_cache_info(param_max_binlog_stmt_cache_size,
                                       param_ptr_binlog_stmt_cache_use,
@@ -587,8 +592,6 @@ class binlog_cache_mngr: public ilist_node<> {
   //Will be reset when gtid is written into binlog
   uchar  gtid_flags3;
   decltype (rpl_gtid::seq_no) sa_seq_no;
-
-  TABLE_SHARE *share;
 private:
 
   binlog_cache_mngr& operator=(const binlog_cache_mngr& info);
@@ -2259,21 +2262,16 @@ static int binlog_commit_flush_xa_prepare(THD *thd, bool all,
 
 #ifdef HAVE_REPLICATION
 static void
-binlog_online_alter_cleanup(ilist<binlog_cache_mngr> &list,
-                            bool ending_trans)
+binlog_online_alter_cleanup(ilist<binlog_cache_data> &list, bool ending_trans)
 {
-  for (auto &cache: list)
-  {
-    cache.reset(true, ending_trans);
-  }
   if (ending_trans)
   {
     auto it= list.begin();
     while (it != list.end())
     {
       auto &cache= *it++;
-      cache.~binlog_cache_mngr();
-      my_free(&cache);
+      cache.reset();
+      delete &cache;
     }
     list.clear();
     DBUG_ASSERT(list.empty());
@@ -5980,7 +5978,7 @@ bool stmt_has_updated_non_trans_table(const THD* thd)
   binlog_hton, which has internal linkage.
 */
 
-binlog_cache_mngr *binlog_setup_cache_mngr(TABLE_SHARE *share)
+binlog_cache_mngr *binlog_setup_cache_mngr()
 {
   auto *cache_mngr= (binlog_cache_mngr*) my_malloc(key_memory_binlog_cache_mngr,
                                   sizeof(binlog_cache_mngr),
@@ -6001,8 +5999,7 @@ binlog_cache_mngr *binlog_setup_cache_mngr(TABLE_SHARE *share)
                             &binlog_stmt_cache_use,
                             &binlog_stmt_cache_disk_use,
                             &binlog_cache_use,
-                            &binlog_cache_disk_use,
-                            share);
+                            &binlog_cache_disk_use);
 
   return cache_mngr;
 }
@@ -6015,7 +6012,7 @@ binlog_cache_mngr *THD::binlog_setup_trx_data()
 
   if (!cache_mngr)
   {
-    cache_mngr= binlog_setup_cache_mngr(NULL);
+    cache_mngr= binlog_setup_cache_mngr();
     thd_set_ha_data(this, binlog_hton, cache_mngr);
   }
 
@@ -6381,9 +6378,27 @@ bool MYSQL_BIN_LOG::write_table_map(THD *thd, TABLE *table, bool with_annotate)
 }
 
 
-binlog_cache_mngr *online_alter_binlog_get_cache_mngr(THD *thd, TABLE *table)
+#ifdef HAVE_REPLICATION
+binlog_cache_data *binlog_setup_cache_data(TABLE_SHARE *share)
 {
-  ilist<binlog_cache_mngr> &list= thd->online_alter_cache_list;
+  auto cache= new binlog_cache_data();
+  if (!cache || open_cached_file(&cache->cache_log, mysql_tmpdir,
+                         LOG_PREFIX, (size_t)binlog_cache_size, MYF(MY_WME)))
+  {
+    delete cache;
+    return NULL;
+  }
+
+  cache->share= share;
+  cache->set_binlog_cache_info(max_binlog_cache_size, &binlog_cache_use,
+                               &binlog_cache_disk_use);
+  cache->store_prev_position();
+  return cache;
+}
+
+binlog_cache_data *online_alter_binlog_get_cache_data(THD *thd, TABLE *table)
+{
+  ilist<binlog_cache_data> &list= thd->online_alter_cache_list;
 
   /* we assume it's very rare to have more than one online ALTER running */
   for (auto &cache: list)
@@ -6392,11 +6407,12 @@ binlog_cache_mngr *online_alter_binlog_get_cache_mngr(THD *thd, TABLE *table)
       return &cache;
   }
 
-  auto *new_cache_mngr= binlog_setup_cache_mngr(table->s);
-  list.push_back(*new_cache_mngr);
+  auto *new_cache_data= binlog_setup_cache_data(table->s);
+  list.push_back(*new_cache_data);
 
-  return new_cache_mngr;
+  return new_cache_data;
 }
+#endif
 
 binlog_cache_mngr *THD::binlog_get_cache_mngr() const
 {
@@ -7654,28 +7670,6 @@ class CacheWriter: public Log_event_writer
   bool first;
 };
 
-#ifdef HAVE_REPLICATION
-static int cache_copy(IO_CACHE *to, IO_CACHE *from)
-{
-  DBUG_ENTER("cache_copy");
-  if (reinit_io_cache(from, READ_CACHE, 0, 0, 0))
-    DBUG_RETURN(ER_ERROR_ON_WRITE);
-  size_t bytes_in_cache= my_b_bytes_in_cache(from);
-
-  do
-  {
-    my_b_write(to, from->read_pos, bytes_in_cache);
-
-    from->read_pos += bytes_in_cache;
-    bytes_in_cache= my_b_fill(from);
-    if (from->error || to->error)
-      DBUG_RETURN(ER_ERROR_ON_WRITE);
-  } while (bytes_in_cache);
-
-  DBUG_RETURN(0);
-}
-#endif
-
 static int binlog_online_alter_commit(THD *thd, bool all)
 {
   DBUG_ENTER("binlog_online_alter_commit");
@@ -7687,28 +7681,21 @@ static int binlog_online_alter_commit(THD *thd, bool all)
 
   bool is_ending_transaction= ending_trans(thd, all);
 
-  for (auto &cache_mngr: thd->online_alter_cache_list)
+  for (auto &cache: thd->online_alter_cache_list)
   {
-    auto *binlog= cache_mngr.share->online_alter_binlog;
+    auto *binlog= cache.share->online_alter_binlog;
     DBUG_ASSERT(binlog);
 
     // do not set STMT_END for last event to leave table open in altering thd
-    error= binlog_flush_pending_rows_event(thd, false, true, binlog,
-                                           is_ending_transaction
-                                           ? &cache_mngr.trx_cache
-                                           : &cache_mngr.stmt_cache);
+    error= binlog_flush_pending_rows_event(thd, false, true, binlog, &cache);
     if (is_ending_transaction)
     {
       mysql_mutex_lock(binlog->get_log_lock());
-      error= binlog->write_cache(thd, &cache_mngr.trx_cache.cache_log);
-
+      error= binlog->write_cache(thd, &cache.cache_log);
       mysql_mutex_unlock(binlog->get_log_lock());
     }
     else
-    {
-      error= cache_copy(&cache_mngr.trx_cache.cache_log,
-                        &cache_mngr.stmt_cache.cache_log);
-    }
+      cache.store_prev_position();
 
     if (error)
     {
@@ -7736,12 +7723,16 @@ static void binlog_online_alter_rollback(THD *thd, bool all)
 #ifdef HAVE_REPLICATION
   bool is_ending_trans= ending_trans(thd, all);
 
+  if (!is_ending_trans)
+    for (auto &cache: thd->online_alter_cache_list)
+      cache.restore_prev_position();
+
   /*
     This is a crucial moment that we are running through
     thd->online_alter_cache_list, and not through thd->open_tables to cleanup
     stmt cache, though both have it. The reason is that the tables can be closed
     to that moment in case of an error.
-    The same reason applies to the fact we don't store cache_mngr in the table
+    The same reason applies to the fact we don't store cache in the table
     itself -- because it can happen to be not existing.
     Still in case if tables are left opened
    */

sql/log.h

@@ -1320,7 +1320,7 @@ int binlog_flush_pending_rows_event(THD *thd, bool stmt_end,
                                     binlog_cache_data *cache_data);
 Rows_log_event* binlog_get_pending_rows_event(binlog_cache_mngr *cache_mngr,
                                               bool use_trans_cache);
-binlog_cache_mngr *online_alter_binlog_get_cache_mngr(THD *thd, TABLE *table);
+binlog_cache_data *online_alter_binlog_get_cache_data(THD *thd, TABLE *table);
 binlog_cache_data* binlog_get_cache_data(binlog_cache_mngr *cache_mngr,
                                          bool use_trans_cache);
 

sql/sql_class.h

@@ -5556,7 +5556,7 @@ class THD: public THD_count, /* this must be first */
   Item *sp_prepare_func_item(Item **it_addr, uint cols);
   bool sp_eval_expr(Field *result_field, Item **expr_item_ptr);
 
-  ilist<binlog_cache_mngr> online_alter_cache_list;
+  ilist<binlog_cache_data> online_alter_cache_list;
 
   bool sql_parser(LEX *old_lex, LEX *lex,
                   char *str, uint str_len, bool stmt_prepare_mode);