Fix for BUG#2083

"EE_ error codes (EE_DELETE, EE_WRITE) end up in the binlog, making slave stop".
The problem was that during execution of the command on the master, an error
can occur (for example, not space left on device, then mysqld waits and when
there is space it completes successfully: so finally it worked but the error
EE_WRITE remains in thd->net.last_errno and thd->net.last_error).
To know if finally the command succeeded, we test the 'error' variable in
every place, and if it shows no failure we reset thd->net.last_err* using
the function THD::clear_error() which is backported from 4.1.
A new test to see if now only real errors get to the binlog (note: the test
uses "rm").

Also a bit of memory free/alloc saving in log_event.cc (do not free the whole
mem_root after every query in the slave SQL thread: we can keep the initial
block of it; which will be freed when the thread terminates).

mysql-test/r/rpl_EE_error.result

+slave stop;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+slave start;
+create table t1 (a int) type=myisam;
+flush tables;
+drop table t1;
+create table t1 (a int, unique(a)) type=myisam;
+set sql_log_bin=0;
+insert into t1 values(2);
+set sql_log_bin=1;
+insert into t1 values(1),(2);
+Duplicate entry '2' for key 1
+drop table t1;

mysql-test/t/rpl_EE_error.test

+# See if an EE_ error in one event of the master's binlog stops replication
+# (it should not: in this configuration the EE_ error is probably not 
+# critical). Example: you do a DROP TABLE on a table which has no MYI file
+# check if START SLAVE, RESET SLAVE, CHANGE MASTER reset Last_slave_error and
+# Last_slave_errno in SHOW SLAVE STATUS (1st and 3rd commands did not: bug 986).
+
+source include/master-slave.inc;
+
+create table t1 (a int) type=myisam;
+flush tables;
+system rm ./var/master-data/test/t1.MYI ;
+drop table t1;
+save_master_pos;
+connection slave;
+sync_with_master;
+
+# Now a real error.
+
+connection master;
+create table t1 (a int, unique(a)) type=myisam;
+set sql_log_bin=0;
+insert into t1 values(2);
+set sql_log_bin=1;
+save_master_pos;
+--error 1062;
+insert into t1 values(1),(2);
+drop table t1;
+save_master_pos;
+connection slave;
+wait_for_slave_to_stop;

sql/log_event.cc

@@ -1922,7 +1922,7 @@ Default database: '%s'",
   // assume no convert for next query unless set explictly
   thd->variables.convert_set = 0;
   close_thread_tables(thd);      
-  free_root(&thd->mem_root,0);
+  free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
   return (thd->query_error ? thd->query_error : Log_event::exec_event(rli)); 
 }
 
@@ -2094,10 +2094,10 @@ Slave: load data infile on table '%s' at log position %s in log \
     slave_print_error(rli,sql_errno,"\
 Error '%s' running LOAD DATA INFILE on table '%s'. Default database: '%s'",
 		      err, (char*)table_name, print_slave_db_safe(db));
-    free_root(&thd->mem_root,0);
+    free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
     return 1;
   }
-  free_root(&thd->mem_root,0);
+  free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
 	    
   if (thd->fatal_error)
   {

sql/sql_acl.cc

@@ -1130,6 +1130,7 @@ bool change_password(THD *thd, const char *host, const char *user,
 		acl_user->user ? acl_user->user : "",
 		acl_user->host.hostname ? acl_user->host.hostname : "",
 		new_password));
+  thd->clear_error();
   mysql_update_log.write(thd, buff, query_length);
   Query_log_event qinfo(thd, buff, query_length, 0);
   mysql_bin_log.write(&qinfo);

sql/sql_base.cc

@@ -575,8 +575,8 @@ void close_temporary_tables(THD *thd)
   if (query && found_user_tables && mysql_bin_log.is_open())
   {
     /* The -1 is to remove last ',' */
+    thd->clear_error();
     Query_log_event qinfo(thd, query, (ulong)(end-query)-1, 0);
-    qinfo.error_code=0;
     mysql_bin_log.write(&qinfo);
   }
   thd->temporary_tables=0;

sql/sql_class.h

@@ -590,6 +590,15 @@ public:
   void add_changed_table(TABLE *table);
   void add_changed_table(const char *key, long key_length);
   CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
+#ifndef EMBEDDED_LIBRARY
+  inline void clear_error()
+  {
+    net.last_error[0]= 0;
+    net.last_errno= 0;
+  }
+#else
+  void clear_error();
+#endif
 };
 
 /* Flags for the THD::system_thread (bitmap) variable */

sql/sql_db.cc

@@ -86,6 +86,7 @@ int mysql_create_db(THD *thd, char *db, uint create_options, bool silent)
       mysql_update_log.write(thd,thd->query, thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
 	mysql_bin_log.write(&qinfo);
       }
@@ -176,6 +177,7 @@ int mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
       mysql_update_log.write(thd, thd->query, thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
 	mysql_bin_log.write(&qinfo);
       }

sql/sql_delete.cc

@@ -175,6 +175,8 @@ cleanup:
     mysql_update_log.write(thd,thd->query, thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      if (error <= 0)
+        thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length, 
 			    log_delayed);
       if (mysql_bin_log.write(&qinfo) && transactional_table)
@@ -479,6 +481,8 @@ bool multi_delete::send_eof()
     mysql_update_log.write(thd,thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      if (error <= 0)
+        thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length,
 			    log_delayed);
       if (mysql_bin_log.write(&qinfo) && !normal_tables)
@@ -591,6 +595,7 @@ end:
       mysql_update_log.write(thd,thd->query,thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length,
 			      thd->tmp_table);
 	mysql_bin_log.write(&qinfo);

sql/sql_insert.cc

@@ -310,6 +310,8 @@ int mysql_insert(THD *thd,TABLE_LIST *table_list, List<Item> &fields,
       mysql_update_log.write(thd, thd->query, thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        if (error <= 0)
+          thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length,
 			      log_delayed);
 	if (mysql_bin_log.write(&qinfo) && transactional_table)
@@ -1196,7 +1198,7 @@ bool delayed_insert::handle_inserts(void)
       table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
       using_ignore=1;
     }
-    thd.net.last_errno = 0; // reset error for binlog
+    thd.clear_error(); // reset error for binlog
     if (write_record(table,&info))
     {
       info.error_count++;				// Ignore errors
@@ -1391,6 +1393,8 @@ bool select_insert::send_eof()
   mysql_update_log.write(thd,thd->query,thd->query_length);
   if (mysql_bin_log.is_open())
   {
+    if (!error)
+      thd->clear_error();
     Query_log_event qinfo(thd, thd->query, thd->query_length,
 			  table->file->has_transactions());
     mysql_bin_log.write(&qinfo);

sql/sql_parse.cc

@@ -2461,6 +2461,7 @@ mysql_execute_command(void)
 	mysql_update_log.write(thd, thd->query, thd->query_length);
 	if (mysql_bin_log.is_open())
 	{
+          thd->clear_error();
 	  Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
 	  mysql_bin_log.write(&qinfo);
 	}
@@ -2481,6 +2482,7 @@ mysql_execute_command(void)
 	mysql_update_log.write(thd, thd->query, thd->query_length);
 	if (mysql_bin_log.is_open())
 	{
+          thd->clear_error();
 	  Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
 	  mysql_bin_log.write(&qinfo);
 	}

sql/sql_rename.cc

@@ -82,6 +82,7 @@ bool mysql_rename_tables(THD *thd, TABLE_LIST *table_list)
     mysql_update_log.write(thd,thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
       mysql_bin_log.write(&qinfo);
     }

sql/sql_table.cc

@@ -237,6 +237,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
       mysql_update_log.write(thd, thd->query,thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length,
 			      tmp_table_deleted && !some_tables_deleted);
 	mysql_bin_log.write(&qinfo);
@@ -779,6 +780,7 @@ int mysql_create_table(THD *thd,const char *db, const char *table_name,
     mysql_update_log.write(thd,thd->query, thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length,
 			    test(create_info->options &
 				 HA_LEX_CREATE_TMP_TABLE));
@@ -1561,6 +1563,7 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
       mysql_update_log.write(thd, thd->query, thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
 	mysql_bin_log.write(&qinfo);
       }
@@ -1931,6 +1934,7 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
     mysql_update_log.write(thd, thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
       mysql_bin_log.write(&qinfo);
     }
@@ -2063,6 +2067,7 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
   mysql_update_log.write(thd, thd->query,thd->query_length);
   if (mysql_bin_log.is_open())
   {
+    thd->clear_error();
     Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
     mysql_bin_log.write(&qinfo);
   }

sql/sql_update.cc

@@ -319,6 +319,8 @@ int mysql_update(THD *thd,
     mysql_update_log.write(thd,thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      if (error <= 0)
+        thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length,
 			    log_delayed);
       if (mysql_bin_log.write(&qinfo) && transactional_table)
@@ -939,6 +941,8 @@ bool multi_update::send_eof()
     mysql_update_log.write(thd,thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
     {
+      if (local_error <= 0)
+        thd->clear_error();
       Query_log_event qinfo(thd, thd->query, thd->query_length,
 			    log_delayed);
       if (mysql_bin_log.write(&qinfo) && trans_safe)