Commit 32db5b4c authored by unknown's avatar unknown
Browse files

when we update thd->db in replication, it's safer to update thd->db_length too. 

This does not fix any known bug, but is still a good idea.


sql/log_event.cc:
  when we update thd->db in replication, it's safer to update thd->db_length too.
sql/slave.cc:
  when we update thd->db in replication, it's safer to update thd->db_length too.
sql/sql_db.cc:
  comment
parent e4ff3438

sql/log_event.cc

+10 −4
Original line number Diff line number Diff line
@@ -1806,7 +1806,7 @@ int Query_log_event::exec_event(struct st_relay_log_info* rli) 
{

  int expected_error, actual_error= 0;

  init_sql_alloc(&thd->mem_root, thd->variables.query_alloc_block_size,0);

  thd->db= (char*) rewrite_db(db);

  thd->db= (char*) rewrite_db(db); // thd->db_length is set later if needed



  /*

    InnoDB internally stores the master log position it has processed so far;
@@ -1836,6 +1836,11 @@ int Query_log_event::exec_event(struct st_relay_log_info* rli) 
  {

    thd->set_time((time_t)when);

    thd->current_tablenr = 0;

    /*

      We cannot use db_len from event to fill thd->db_length, because

      rewrite_db() may have changed db.

    */ 

    thd->db_length= thd->db ? strlen(thd->db) : 0;

    thd->query_length= q_len;

    thd->query= (char *) query;

    VOID(pthread_mutex_lock(&LOCK_thread_count));
@@ -1930,7 +1935,7 @@ Default database: '%s'. Query: '%s'", 
  VOID(pthread_mutex_lock(&LOCK_thread_count));

  thd->db= 0;	                        // prevent db from being freed

  thd->query= 0;			// just to be sure

  thd->query_length= 0;

  thd->query_length= thd->db_length =0;

  VOID(pthread_mutex_unlock(&LOCK_thread_count));

  close_thread_tables(thd);      

  free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
@@ -1968,7 +1973,7 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli, 
{

  char *load_data_query= 0;

  init_sql_alloc(&thd->mem_root, thd->variables.query_alloc_block_size, 0);

  thd->db= (char*) rewrite_db(db);

  thd->db= (char*) rewrite_db(db); // thd->db_length is set later if needed

  DBUG_ASSERT(thd->query == 0);

  clear_all_errors(thd, rli);
@@ -2001,6 +2006,7 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli, 
  {

    thd->set_time((time_t)when);

    thd->current_tablenr = 0;

    thd->db_length= thd->db ? strlen(thd->db) : 0;

    VOID(pthread_mutex_lock(&LOCK_thread_count));

    thd->query_id = query_id++;

    VOID(pthread_mutex_unlock(&LOCK_thread_count));
@@ -2117,7 +2123,7 @@ Slave: load data infile on table '%s' at log position %s in log \ 
  VOID(pthread_mutex_lock(&LOCK_thread_count));

  thd->db= 0;

  thd->query= 0;

  thd->query_length= 0;

  thd->query_length= thd->db_length= 0;

  VOID(pthread_mutex_unlock(&LOCK_thread_count));

  close_thread_tables(thd);

  if (load_data_query)

sql/slave.cc

+9 −4
Original line number Diff line number Diff line
@@ -1124,6 +1124,7 @@ slaves can't replicate a 5.0 or newer master."; 
  Used by fetch_master_table (used by LOAD TABLE tblname FROM MASTER and LOAD

  DATA FROM MASTER). Drops the table (if 'overwrite' is true) and recreates it

  from the dump. Honours replication inclusion/exclusion rules.

  db must be non-zero (guarded by assertion).



  RETURN VALUES

    0           success
@@ -1134,8 +1135,8 @@ static int create_table_from_dump(THD* thd, NET* net, const char* db, 
				  const char* table_name, bool overwrite)

{

  ulong packet_len = my_net_read(net); // read create table statement

  char *query;

  char* save_db;

  char *query, *save_db;

  uint32 save_db_length;

  Vio* save_vio;

  HA_CHECK_OPT check_opt;

  TABLE_LIST tables;
@@ -1193,9 +1194,13 @@ static int create_table_from_dump(THD* thd, NET* net, const char* db, 
  thd->proc_info = "Creating table from master dump";

  // save old db in case we are creating in a different database

  save_db = thd->db;

  save_db_length= thd->db_length;

  thd->db = (char*)db;

  DBUG_ASSERT(thd->db);

  thd->db_length= strlen(thd->db);

  mysql_parse(thd, thd->query, packet_len); // run create table

  thd->db = save_db;		// leave things the way the were before

  thd->db_length= save_db_length;

  thd->options = save_options;

  

  if (thd->query_error)
@@ -2689,7 +2694,7 @@ log space"); 
		  IO_RPL_LOG_NAME, llstr(mi->master_log_pos,llbuff));

  VOID(pthread_mutex_lock(&LOCK_thread_count));

  thd->query = thd->db = 0; // extra safety

  thd->query_length = 0;

  thd->query_length= thd->db_length= 0;

  VOID(pthread_mutex_unlock(&LOCK_thread_count));

  if (mysql)

  {
@@ -2838,7 +2843,7 @@ the slave SQL thread with \"SLAVE START\". We stopped at log \ 
 err:

  VOID(pthread_mutex_lock(&LOCK_thread_count));

  thd->query = thd->db = 0; // extra safety

  thd->query_length = 0;

  thd->query_length= thd->db_length= 0;

  VOID(pthread_mutex_unlock(&LOCK_thread_count));

  thd->proc_info = "Waiting for slave mutex on exit";

  pthread_mutex_lock(&rli->run_lock);

sql/sql_db.cc

+9 −0
Original line number Diff line number Diff line
@@ -385,6 +385,15 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db, 
}





/*

  Changes the current database.



  NOTES

    Do as little as possible in this function, as it is not called for the

    replication slave SQL thread (for that thread, setting of thd->db is done

    in ::exec_event() methods of log_event.cc).

*/



bool mysql_change_db(THD *thd,const char *name)

{

  int length, db_length;