MDEV-16329 [3/5] use binlog_cache_data directly in most places

* Eliminate most usages of THD::use_trans_table. Only 3 left, and they are
  at quite high levels, and really essential.
* Eliminate is_transactional argument when possible. Lots of places are
  left though, because of some WSREP error handling in
  MYSQL_BIN_LOG::set_write_error.
* Remove junk binlog functions from THD
* binlog_prepare_pending_rows_event is moved to log.cc inside MYSQL_BIN_LOG
  and is not anymore template. Instead it accepls event factory with a type
  code, and a callback to a constructing function in it.

sql/handler.cc

@@ -7269,7 +7269,9 @@ int handler::binlog_log_row(TABLE *table,
   if (thd->variables.option_bits & OPTION_GTID_BEGIN)
     is_trans= 1;
 
-  bool error= (*log_func)(thd, table, &mysql_bin_log, cache_mngr,
+  auto *cache= binlog_get_cache_data(cache_mngr, use_trans_cache(thd, is_trans));
+
+  bool error= (*log_func)(thd, table, &mysql_bin_log, cache,
                           is_trans, before_record, after_record);
   DBUG_RETURN(error ? HA_ERR_RBR_LOGGING_FAILED : 0);
 }

sql/handler.h

@@ -656,8 +656,8 @@ given at all. */
 typedef ulonglong alter_table_operations;
 
 class MYSQL_BIN_LOG;
-class binlog_cache_mngr;
-typedef bool Log_func(THD*, TABLE*, MYSQL_BIN_LOG *, binlog_cache_mngr *, bool,
+class binlog_cache_data;
+typedef bool Log_func(THD*, TABLE*, MYSQL_BIN_LOG *, binlog_cache_data *, bool,
                       const uchar*, const uchar*);
 
 /*

sql/log.cc

@@ -2055,29 +2055,31 @@ static int
 binlog_truncate_trx_cache(THD *thd, binlog_cache_mngr *cache_mngr, bool all)
 {
   DBUG_ENTER("binlog_truncate_trx_cache");
+
+  if(!WSREP_EMULATE_BINLOG_NNULL(thd) && !mysql_bin_log.is_open())
+    DBUG_RETURN(0);
+
   int error=0;
-  /*
-    This function handles transactional changes and as such this flag
-    equals to true.
-  */
-  bool const is_transactional= TRUE;
 
   DBUG_PRINT("info", ("thd->options={ %s %s}, transaction: %s",
                       FLAGSTR(thd->variables.option_bits, OPTION_NOT_AUTOCOMMIT),
                       FLAGSTR(thd->variables.option_bits, OPTION_BEGIN),
                       all ? "all" : "stmt"));
 
-  thd->binlog_remove_pending_rows_event(TRUE, is_transactional);
+  auto &trx_cache= cache_mngr->trx_cache;
+  MYSQL_BIN_LOG::remove_pending_rows_event(thd, &trx_cache);
+  thd->reset_binlog_for_next_statement();
+
   /*
     If rolling back an entire transaction or a single statement not
     inside a transaction, we reset the transaction cache.
   */
   if (ending_trans(thd, all))
   {
-    if (cache_mngr->trx_cache.has_incident())
+    if (trx_cache.has_incident())
       error= mysql_bin_log.write_incident(thd);
 
-    thd->reset_binlog_for_next_statement();
+    DBUG_ASSERT(thd->binlog_table_maps == 0);
 
     cache_mngr->reset(false, true);
   }
@@ -2086,9 +2088,9 @@ binlog_truncate_trx_cache(THD *thd, binlog_cache_mngr *cache_mngr, bool all)
     transaction cache to remove the statement.
   */
   else
-    cache_mngr->trx_cache.restore_prev_position();
+    trx_cache.restore_prev_position();
 
-  DBUG_ASSERT(cache_mngr->trx_cache.pending() == NULL);
+  DBUG_ASSERT(trx_cache.pending() == NULL);
   DBUG_RETURN(error);
 }
 
@@ -2406,7 +2408,7 @@ static int binlog_rollback(handlerton *hton, THD *thd, bool all)
     thd->reset_binlog_for_next_statement();
     DBUG_RETURN(error);
   }
-  if (!wsrep_emulate_bin_log && mysql_bin_log.check_write_error(thd))
+  if (!wsrep_emulate_bin_log && MYSQL_BIN_LOG::check_write_error(thd))
   {
     /*
       "all == true" means that a "rollback statement" triggered the error and
@@ -2458,12 +2460,13 @@ static int binlog_rollback(handlerton *hton, THD *thd, bool all)
 
 void binlog_reset_cache(THD *thd)
 {
-  binlog_cache_mngr *const cache_mngr= opt_bin_log ? 
+  binlog_cache_mngr *const cache_mngr= opt_bin_log ?
                                        thd->binlog_get_cache_mngr() : 0;
   DBUG_ENTER("binlog_reset_cache");
   if (cache_mngr)
   {
-    thd->binlog_remove_pending_rows_event(TRUE, TRUE);
+    MYSQL_BIN_LOG::remove_pending_rows_event(thd, &cache_mngr->trx_cache);
+    thd->reset_binlog_for_next_statement();
     cache_mngr->reset(true, true);
   }
   DBUG_VOID_RETURN;
@@ -6318,30 +6321,31 @@ binlog_cache_mngr *THD::binlog_get_cache_mngr() const
 Rows_log_event* binlog_get_pending_rows_event(binlog_cache_mngr *cache_mngr,
                                               bool use_trans_cache)
 {
+  DBUG_ASSERT(cache_mngr);
   Rows_log_event* rows= NULL;
 
-  /*
-    This is less than ideal, but here's the story: If there is no cache_mngr,
-    prepare_pending_rows_event() has never been called (since the cache_mngr
-    is set up there). In that case, we just return NULL.
-   */
   if (cache_mngr)
     rows= cache_mngr->get_binlog_cache_data(use_trans_cache)->pending();
   return rows;
 }
 
+binlog_cache_data* binlog_get_cache_data(binlog_cache_mngr *cache_mngr,
+                                         bool use_trans_cache)
+{
+  return cache_mngr->get_binlog_cache_data(use_trans_cache);
+}
+
 int binlog_flush_pending_rows_event(THD *thd, bool stmt_end,
                                     bool is_transactional,
                                     MYSQL_BIN_LOG *bin_log,
-                                    binlog_cache_mngr *cache_mngr,
-                                    bool use_trans_cache)
+                                    binlog_cache_data *cache_data)
 {
   /*
     Mark the event as the last event of a statement if the stmt_end
     flag is set.
   */
   int error= 0;
-  auto *pending= cache_mngr->get_binlog_cache_data(use_trans_cache)->pending();
+  auto *pending= cache_data->pending();
   if (pending)
   {
     if (stmt_end)
@@ -6350,36 +6354,12 @@ int binlog_flush_pending_rows_event(THD *thd, bool stmt_end,
       thd->reset_binlog_for_next_statement();
     }
 
-    error= bin_log->flush_and_set_pending_rows_event(thd, 0, cache_mngr,
+    error= bin_log->flush_and_set_pending_rows_event(thd, 0, cache_data,
                                                      is_transactional);
   }
   return error;
 }
 
-/**
-  This function stores a pending row event into a cache which is specified
-  through the parameter @c is_transactional. Respectively, when it is @c
-  true, the pending event is stored into the transactional cache. Otherwise
-  into the non-transactional cache.
-
-  @param evt               a pointer to the row event.
-  @param use_trans_cache   @c true indicates a transactional cache,
-                           otherwise @c false a non-transactional.
-*/
-void
-THD::binlog_set_pending_rows_event(Rows_log_event* ev, bool use_trans_cache)
-{
-  binlog_cache_mngr *const cache_mngr= binlog_setup_trx_data();
-
-  DBUG_ASSERT(cache_mngr);
-
-  binlog_cache_data *cache_data=
-    cache_mngr->get_binlog_cache_data(use_trans_cache);
-
-  cache_data->set_pending(ev);
-}
-
-
 /**
   This function removes the pending rows event, discarding any outstanding
   rows. If there is no pending rows event available, this is effectively a
@@ -6390,17 +6370,10 @@ THD::binlog_set_pending_rows_event(Rows_log_event* ev, bool use_trans_cache)
                            otherwise @c false a non-transactional.
 */
 int
-MYSQL_BIN_LOG::remove_pending_rows_event(THD *thd, bool is_transactional)
+MYSQL_BIN_LOG::remove_pending_rows_event(THD *thd, binlog_cache_data *cache_data)
 {
   DBUG_ENTER("MYSQL_BIN_LOG::remove_pending_rows_event");
 
-  binlog_cache_mngr *const cache_mngr= thd->binlog_get_cache_mngr();
-
-  DBUG_ASSERT(cache_mngr);
-
-  binlog_cache_data *cache_data=
-    cache_mngr->get_binlog_cache_data(use_trans_cache(thd, is_transactional));
-
   if (Rows_log_event* pending= cache_data->pending())
   {
     delete pending;
@@ -6414,6 +6387,7 @@ MYSQL_BIN_LOG::remove_pending_rows_event(THD *thd, bool is_transactional)
   Moves the last bunch of rows from the pending Rows event to a cache (either
   transactional cache if is_transaction is @c true, or the non-transactional
   cache otherwise. Sets a new pending event.
+  In case of error during flushing, sets write_error=1 to itself.
 
   @param thd               a pointer to the user thread.
   @param evt               a pointer to the row event.
@@ -6423,19 +6397,13 @@ MYSQL_BIN_LOG::remove_pending_rows_event(THD *thd, bool is_transactional)
 int
 MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
                                                 Rows_log_event* event,
-                                                binlog_cache_mngr *cache_mngr,
+                                                binlog_cache_data *cache_data,
                                                 bool is_transactional)
 {
   DBUG_ENTER("MYSQL_BIN_LOG::flush_and_set_pending_rows_event(event)");
   DBUG_ASSERT(WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open());
   DBUG_PRINT("enter", ("event: %p", event));
 
-  DBUG_ASSERT(cache_mngr);
-
-  bool should_use_trans_cache= use_trans_cache(thd, is_transactional);
-  binlog_cache_data *cache_data=
-    cache_mngr->get_binlog_cache_data(should_use_trans_cache);
-
   DBUG_PRINT("info", ("cache_mngr->pending(): %p", cache_data->pending()));
 
   if (Rows_log_event* pending= cache_data->pending())
@@ -6463,11 +6431,89 @@ MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
     delete pending;
   }
 
-  thd->binlog_set_pending_rows_event(event, should_use_trans_cache);
+  cache_data->set_pending(event);
 
   DBUG_RETURN(0);
 }
 
+/*
+  Member function for ensuring that there is an rows log
+  event of the apropriate type before proceeding.
+
+  POST CONDITION:
+    If a non-NULL pointer is returned, the pending event for thread 'thd' will
+    be an event created by callback hold by event_factory, and
+    will be either empty or have enough space to hold 'needed' bytes.
+    In addition, the columns bitmap will be correct for the row, meaning that
+    the pending event will be flushed if the columns in the event differ from
+    the columns suppled to the function.
+
+  RETURNS
+    If no error, a non-NULL pending event (either one which already existed or
+    the newly created one).
+    If error, NULL.
+ */
+
+Rows_log_event*
+MYSQL_BIN_LOG::prepare_pending_rows_event(THD *thd, TABLE* table,
+                                          binlog_cache_data *cache_data,
+                                          uint32 serv_id, size_t needed,
+                                          bool is_transactional,
+                                          Rows_event_factory event_factory)
+{
+  DBUG_ENTER("MYSQL_BIN_LOG::prepare_pending_rows_event");
+  /* Pre-conditions */
+  DBUG_ASSERT(table->s->table_map_id != ~0UL);
+
+  /*
+    There is no good place to set up the transactional data, so we
+    have to do it here.
+  */
+  Rows_log_event* pending= cache_data->pending();
+
+  if (unlikely(pending && !pending->is_valid()))
+    DBUG_RETURN(NULL);
+
+  /*
+    Check if the current event is non-NULL and a write-rows
+    event. Also check if the table provided is mapped: if it is not,
+    then we have switched to writing to a new table.
+    If there is no pending event, we need to create one. If there is a pending
+    event, but it's not about the same table id, or not of the same type
+    (between Write, Update and Delete), or not the same affected columns, or
+    going to be too big, flush this event to disk and create a new pending
+    event.
+  */
+  if (!pending ||
+      pending->server_id != serv_id ||
+      pending->get_table_id() != table->s->table_map_id ||
+      pending->get_general_type_code() != event_factory.type_code ||
+      pending->get_data_size() + needed > opt_binlog_rows_event_max_size ||
+      pending->read_write_bitmaps_cmp(table) == FALSE)
+  {
+    /* Create a new RowsEventT... */
+    Rows_log_event* const
+            ev= event_factory.create(thd, table, table->s->table_map_id,
+                                     is_transactional);
+    if (unlikely(!ev))
+      DBUG_RETURN(NULL);
+    ev->server_id= serv_id; // I don't like this, it's too easy to forget.
+    /*
+      flush the pending event and replace it with the newly created
+      event...
+    */
+    if (unlikely(flush_and_set_pending_rows_event(thd, ev, cache_data,
+                                                  is_transactional)))
+    {
+      delete ev;
+      DBUG_RETURN(NULL);
+    }
+
+    DBUG_RETURN(ev);               /* This is the new pending event */
+  }
+  DBUG_RETURN(pending);        /* This is the current pending event */
+}
+
 
 /* Generate a new global transaction ID, and write it to the binlog */
 
@@ -12108,7 +12154,8 @@ void wsrep_thd_binlog_stmt_rollback(THD * thd)
   binlog_cache_mngr *const cache_mngr= thd->binlog_get_cache_mngr();
   if (cache_mngr)
   {
-    thd->binlog_remove_pending_rows_event(TRUE, TRUE);
+    MYSQL_BIN_LOG::remove_pending_rows_event(thd, &cache_mngr->trx_cache);
+    thd->reset_binlog_for_next_statement();
     cache_mngr->stmt_cache.reset();
   }
   DBUG_VOID_RETURN;