Commit 308b6792 authored by unknown's avatar unknown

Bug#4118: multi-table UPDATE takes WRITE lock on read table

  Ensures that WRITE lock is not obtained on all tables referenced.


mysql-test/r/lock_multi.result:
  Bug#4118
    New test for multi-update locking
mysql-test/r/multi_update.result:
  Bug#4118
    Fix test
mysql-test/t/lock_multi.test:
  Bug#4118
    New test for multi-update locking
mysql-test/t/multi_update.test:
  Bug#4118
    Fix test
sql/sql_parse.cc:
  Bug#4118
    Split multi-update to its own case statement in sql_parse.cc
sql/sql_update.cc:
  Bug#4118
    Overview of locking checking:    
      1. Open and acquire READ lock
      2. Check to see which tables need WRITE lock
      3. Unlock tables and relock
sql/sql_yacc.yy:
  Bug#4118
    Split multi-update to its own case statement in sql_parse.cc
parent 3a9e48e4
...@@ -17,6 +17,18 @@ unlock tables; ...@@ -17,6 +17,18 @@ unlock tables;
n n
1 1
drop table t1; drop table t1;
create table t1 (a int, b int);
create table t2 (c int, d int);
insert into t1 values(1,1);
insert into t1 values(2,2);
insert into t2 values(1,2);
lock table t1 read;
update t1,t2 set c=a where b=d;
select c from t2;
c
2
drop table t1;
drop table t2;
create table t1 (a int); create table t1 (a int);
create table t2 (a int); create table t2 (a int);
lock table t1 write, t2 write; lock table t1 write, t2 write;
......
...@@ -151,7 +151,6 @@ Table 't2' was locked with a READ lock and can't be updated ...@@ -151,7 +151,6 @@ Table 't2' was locked with a READ lock and can't be updated
UPDATE t1,t2 SET t1.d=t2.d,t2.d=30 WHERE t1.n=t2.n; UPDATE t1,t2 SET t1.d=t2.d,t2.d=30 WHERE t1.n=t2.n;
Table 't2' was locked with a READ lock and can't be updated Table 't2' was locked with a READ lock and can't be updated
UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n; UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n;
Table 't2' was locked with a READ lock and can't be updated
unlock tables; unlock tables;
LOCK TABLES t1 write, t2 write; LOCK TABLES t1 write, t2 write;
UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n; UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n;
......
...@@ -50,6 +50,30 @@ connection reader; ...@@ -50,6 +50,30 @@ connection reader;
reap; reap;
drop table t1; drop table t1;
#
# Test problem when using locks with multi-updates
# It should not block when multi-update is reading on a read-locked table
#
connection locker;
create table t1 (a int, b int);
create table t2 (c int, d int);
insert into t1 values(1,1);
insert into t1 values(2,2);
insert into t2 values(1,2);
lock table t1 read;
connection writer;
--sleep 2
send update t1,t2 set c=a where b=d;
connection reader;
--sleep 2
select c from t2;
connection writer;
reap;
connection locker;
drop table t1;
drop table t2;
# #
# Test problem when using locks on many tables and droping a table that # Test problem when using locks on many tables and droping a table that
# is to-be-locked by another thread # is to-be-locked by another thread
......
...@@ -151,8 +151,6 @@ LOCK TABLES t1 write, t2 read; ...@@ -151,8 +151,6 @@ LOCK TABLES t1 write, t2 read;
DELETE t1.*, t2.* FROM t1,t2 where t1.n=t2.n; DELETE t1.*, t2.* FROM t1,t2 where t1.n=t2.n;
--error 1099 --error 1099
UPDATE t1,t2 SET t1.d=t2.d,t2.d=30 WHERE t1.n=t2.n; UPDATE t1,t2 SET t1.d=t2.d,t2.d=30 WHERE t1.n=t2.n;
# The following should be fixed to not give an error
--error 1099
UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n; UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n;
unlock tables; unlock tables;
LOCK TABLES t1 write, t2 write; LOCK TABLES t1 write, t2 write;
......
...@@ -1927,21 +1927,26 @@ mysql_execute_command(void) ...@@ -1927,21 +1927,26 @@ mysql_execute_command(void)
send_error(&thd->net,ER_WRONG_VALUE_COUNT); send_error(&thd->net,ER_WRONG_VALUE_COUNT);
DBUG_VOID_RETURN; DBUG_VOID_RETURN;
} }
if (select_lex->table_list.elements == 1) if (check_one_table_access(thd, UPDATE_ACL, tables, 0))
{ goto error; /* purecov: inspected */
if (check_one_table_access(thd, UPDATE_ACL, tables, 0))
goto error; /* purecov: inspected */
res= mysql_update(thd,tables, res= mysql_update(thd,tables,
select_lex->item_list, select_lex->item_list,
lex->value_list, lex->value_list,
select_lex->where, select_lex->where,
(ORDER *) select_lex->order_list.first, (ORDER *) select_lex->order_list.first,
select_lex->select_limit, select_lex->select_limit,
lex->duplicates); lex->duplicates);
break;
case SQLCOM_MULTI_UPDATE:
if (check_db_used(thd,tables))
goto error;
if (select_lex->item_list.elements != lex->value_list.elements)
{
send_error(&thd->net,ER_WRONG_VALUE_COUNT);
DBUG_VOID_RETURN;
} }
else
{ {
const char *msg= 0; const char *msg= 0;
TABLE_LIST *table; TABLE_LIST *table;
......
...@@ -401,25 +401,101 @@ int mysql_multi_update(THD *thd, ...@@ -401,25 +401,101 @@ int mysql_multi_update(THD *thd,
int res; int res;
multi_update *result; multi_update *result;
TABLE_LIST *tl; TABLE_LIST *tl;
const bool locked= !(thd->locked_tables);
DBUG_ENTER("mysql_multi_update"); DBUG_ENTER("mysql_multi_update");
if ((res=open_and_lock_tables(thd,table_list))) for (;;)
DBUG_RETURN(res); {
table_map update_map= 0;
int tnr= 0;
if ((res= open_tables(thd, table_list)))
DBUG_RETURN(res);
thd->select_limit=HA_POS_ERROR; /*
Only need to call lock_tables if (thd->locked_tables == NULL)
*/
if (locked && ((res= lock_tables(thd, table_list))))
DBUG_RETURN(res);
/* thd->select_limit=HA_POS_ERROR;
Ensure that we have update privilege for all tables and columns in the
SET part
*/
for (tl= table_list ; tl ; tl=tl->next)
{
TABLE *table= tl->table;
table->grant.want_privilege= (UPDATE_ACL & ~table->grant.privilege);
}
if (setup_fields(thd, table_list, *fields, 1, 0, 0)) /*
DBUG_RETURN(-1); Ensure that we have update privilege for all tables and columns in the
SET part
While we are here, initialize the table->map field.
*/
for (tl= table_list ; tl ; tl=tl->next)
{
TABLE *table= tl->table;
table->grant.want_privilege= (UPDATE_ACL & ~table->grant.privilege);
table->map= (table_map) 1 << (tnr++);
}
if (!setup_fields(thd, table_list, *fields, 1, 0, 0))
{
List_iterator_fast<Item> field_it(*fields);
Item_field *item;
while ((item= (Item_field *) field_it++))
update_map|= item->used_tables();
DBUG_PRINT("info",("update_map=0x%08x", update_map));
}
else
DBUG_RETURN(-1);
/*
Unlock the tables in preparation for relocking
*/
if (locked)
{
pthread_mutex_lock(&LOCK_open);
mysql_unlock_tables(thd, thd->lock);
thd->lock= 0;
pthread_mutex_unlock(&LOCK_open);
}
/*
Set the table locking strategy according to the update map
*/
for (tl= table_list ; tl ; tl=tl->next)
{
TABLE *table= tl->table;
if (update_map & table->map)
{
DBUG_PRINT("info",("setting table `%s` for update", tl->alias));
tl->lock_type= thd->lex.lock_option;
tl->updating= 1;
}
else
{
DBUG_PRINT("info",("setting table `%s` for read-only", tl->alias));
tl->lock_type= TL_READ;
tl->updating= 0;
}
if (locked)
tl->table->reginfo.lock_type= tl->lock_type;
}
/*
Relock the tables
*/
if (!(res=lock_tables(thd,table_list)))
break;
if (!locked)
DBUG_RETURN(res);
List_iterator_fast<Item> field_it(*fields);
Item_field *item;
while ((item= (Item_field *) field_it++))
/* item->cleanup(); XXX Use this instead in MySQL 4.1+ */
item->field= item->result_field= 0;
close_thread_tables(thd);
}
/* /*
Count tables and setup timestamp handling Count tables and setup timestamp handling
......
...@@ -2751,10 +2751,18 @@ update: ...@@ -2751,10 +2751,18 @@ update:
lex->select->order_list.next= (byte**) &lex->select->order_list.first; lex->select->order_list.next= (byte**) &lex->select->order_list.first;
} }
opt_low_priority opt_ignore join_table_list opt_low_priority opt_ignore join_table_list
SET update_list where_clause opt_order_clause delete_limit_clause SET update_list
{ {
set_lock_for_tables($3); if (Lex->select->table_list.elements > 1)
{
LEX *lex=Lex;
lex->sql_command= SQLCOM_MULTI_UPDATE;
lex->lock_option= $3;
}
else
set_lock_for_tables($3);
} }
where_clause opt_order_clause delete_limit_clause {}
; ;
update_list: update_list:
......
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