MDEV-11675. Cleanup around mysql_client_binlog_statement to simplify

logics as well as optimize memory usage.

3 files changed, 75 insertions, 41 deletions

diff --git a/sql/log.cc b/sql/log.cc
index 9c8c62301ae..628d1c8a1d9 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -586,7 +586,16 @@ private:
   binlog_cache_mngr(const binlog_cache_mngr& info);
 };
 
-// TODO: rename and add header
+/**
+  The function handles the first phase of two-phase binlogged ALTER.
+  On master binlogs START ALTER when that is configured to do so.
+  On slave START ALTER gets binlogged and its gtid committed into gtid slave pos
+  table.
+
+  @return  false on success, true on failure
+  @return  @c partial_alter set to @c true when START ALTER phase
+           has been completed
+*/
 bool write_bin_log_start_alter(THD *thd, bool& partial_alter,
                                uint64 start_alter_id, bool if_exists,
                                MEM_ROOT *mem)
diff --git a/sql/log_event_server.cc b/sql/log_event_server.cc
index c73656571e3..04f43265647 100644
--- a/sql/log_event_server.cc
+++ b/sql/log_event_server.cc
@@ -1962,7 +1962,7 @@ int Query_log_event::do_apply_event(rpl_group_info *rgi,
       if (charset_inited)
       {
         rpl_sql_thread_info *sql_info= thd->system_thread_info.rpl_sql_info;
-        if (sql_info->cached_charset_compare(charset))
+        if (thd->slave_thread && sql_info->cached_charset_compare(charset))
         {
           /* Verify that we support the charsets found in the event. */
           if (!(thd->variables.character_set_client=
diff --git a/sql/sql_binlog.cc b/sql/sql_binlog.cc
index 74d2bba39f8..b784fccd318 100644
--- a/sql/sql_binlog.cc
+++ b/sql/sql_binlog.cc
@@ -169,6 +169,66 @@ int binlog_defragment(THD *thd)
   return 0;
 }
 
+/**
+  Wraps Log_event::apply_event to save and restore
+  session context in case of Query_log_event.
+
+  @return
+    0         on success,
+    non-zero  otherwise.
+*/
+#if !defined(MYSQL_CLIENT) && defined(HAVE_REPLICATION)
+int save_restore_context_apply_event(Log_event *ev, rpl_group_info *rgi)
+{
+  int err= 0;
+  THD *thd= rgi->thd;
+  Relay_log_info *rli= thd->rli_fake;
+  sql_digest_state *m_digest;
+  PSI_statement_locker *m_statement_psi;
+  LEX_CSTRING save_db;
+  my_thread_id m_thread_id= 0;
+  LEX_CSTRING connection_name= { STRING_WITH_LEN("BINLOG_BASE64_EVENT") };
+
+  DBUG_ASSERT(!rli->mi);
+
+  if (ev->get_type_code() == QUERY_EVENT)
+  {
+    m_digest= thd->m_digest;
+    m_statement_psi= thd->m_statement_psi;
+    m_thread_id= thd->variables.pseudo_thread_id;
+    thd->system_thread_info.rpl_sql_info= NULL;
+
+    if ((rli->mi= new Master_info(&connection_name, false)))
+    {
+      save_db= thd->db;
+      thd->reset_db(&null_clex_str);
+    }
+    else
+    {
+      my_error(ER_OUT_OF_RESOURCES, MYF(0));
+      err= -1;
+      goto end;
+    }
+    thd->m_digest= NULL;
+    thd->m_statement_psi= NULL;
+  }
+
+  err= ev->apply_event(rgi);
+
+end:
+  if (ev->get_type_code() == QUERY_EVENT)
+  {
+    thd->m_digest= m_digest;
+    thd->m_statement_psi= m_statement_psi;
+    thd->variables.pseudo_thread_id= m_thread_id;
+    thd->reset_db(&save_db);
+    delete rli->mi;
+    rli->mi= NULL;
+  }
+
+  return err;
+}
+#endif
 
 /**
   Execute a BINLOG statement.
@@ -215,23 +275,12 @@ void mysql_client_binlog_statement(THD* thd)
   rli= thd->rli_fake;
   if (!rli && (rli= thd->rli_fake= new Relay_log_info(FALSE, "BINLOG_BASE64_EVENT")))
     rli->sql_driver_thd= thd;
-  //static LEX_CSTRING connection_name= { STRING_WITH_LEN("BINLOG_BASE64_EVENT") };
-  //rli->mi= new Master_info(&connection_name, false);
   if (!(rgi= thd->rgi_fake))
     rgi= thd->rgi_fake= new rpl_group_info(rli);
   rgi->thd= thd;
-  thd->system_thread_info.rpl_sql_info=
-    //new rpl_sql_thread_info(rli->mi->rpl_filter);
-    new rpl_sql_thread_info(NULL);
   const char *error= 0;
   Log_event *ev = 0;
   my_bool is_fragmented= FALSE;
-#if !defined(MYSQL_CLIENT) && defined(HAVE_REPLICATION)
-  sql_digest_state *m_digest;
-  PSI_statement_locker *m_statement_psi;
-  LEX_CSTRING save_db;
-  my_thread_id thread_id= 0;
-#endif
   /*
     Out of memory check
   */
@@ -384,30 +433,7 @@ void mysql_client_binlog_statement(THD* thd)
         LEX *backup_lex;
 
         thd->backup_and_reset_current_lex(&backup_lex);
-        if (ev->get_type_code() == QUERY_EVENT)
-        {
-          m_digest= thd->m_digest;
-          m_statement_psi= thd->m_statement_psi;
-          save_db.str= my_strndup(key_memory_THD_db, thd->db.str,
-              thd->db.length, MYF(MY_WME));
-          save_db.length= thd->db.length;
-          if (save_db.str == NULL)
-          {
-            my_error(ER_OUT_OF_RESOURCES, MYF(0));
-            goto end;
-          }
-          thd->m_digest= NULL;
-          thd->m_statement_psi= NULL;
-          thread_id= thd->variables.pseudo_thread_id;
-        }
-        err= ev->apply_event(rgi);
-        if (ev->get_type_code() == QUERY_EVENT)
-        {
-          thd->m_digest= m_digest;
-          thd->m_statement_psi= m_statement_psi;
-          thd->reset_db(&save_db);
-          thd->variables.pseudo_thread_id= thread_id;
-        }
+        err= save_restore_context_apply_event(ev, rgi);
         thd->restore_current_lex(backup_lex);
       }
       thd->variables.option_bits=
@@ -423,7 +449,7 @@ void mysql_client_binlog_statement(THD* thd)
         i.e. when this thread terminates.
       */
       if (ev->get_type_code() != FORMAT_DESCRIPTION_EVENT)
-        delete ev; 
+        delete ev;
       ev= 0;
       if (err)
       {
@@ -431,7 +457,8 @@ void mysql_client_binlog_statement(THD* thd)
           TODO: Maybe a better error message since the BINLOG statement
           now contains several events.
         */
-        my_error(ER_UNKNOWN_ERROR, MYF(0));
+        if (!thd->is_error())
+          my_error(ER_UNKNOWN_ERROR, MYF(0));
         goto end;
       }
     }
@@ -447,8 +474,6 @@ end:
   thd->variables.option_bits= thd_options;
   rgi->slave_close_thread_tables(thd);
   my_free(buf);
-  //delete rli->mi;
-  delete thd->system_thread_info.rpl_sql_info;
   delete rgi;
   rgi= thd->rgi_fake= NULL;
   DBUG_VOID_RETURN;