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mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00

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
This commit is contained in:
unknown
2004-10-03 00:20:47 +01:00
parent 799505216f
commit a49f5cae9a
7 changed files with 155 additions and 33 deletions

View File

@ -17,6 +17,18 @@ unlock tables;
n
1
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 t2 (a int);
lock table t1 write, t2 write;

View File

@ -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;
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;
Table 't2' was locked with a READ lock and can't be updated
unlock tables;
LOCK TABLES t1 write, t2 write;
UPDATE t1,t2 SET t1.d=t2.d WHERE t1.n=t2.n;

View File

@ -50,6 +50,30 @@ connection reader;
reap;
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
# is to-be-locked by another thread

View File

@ -151,8 +151,6 @@ LOCK TABLES t1 write, t2 read;
DELETE t1.*, t2.* FROM t1,t2 where t1.n=t2.n;
--error 1099
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;
unlock tables;
LOCK TABLES t1 write, t2 write;