Commit 32db5b4c authored by unknown's avatar unknown

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
......@@ -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 @@ end:
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)
......
......@@ -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 @@ err:
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);
......
......@@ -385,6 +385,15 @@ err:
}
/*
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;
......
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