Commit 5397f8c9 authored by ramil/ram@mysql.com/ramil.myoffice.izhnet.ru's avatar ramil/ram@mysql.com/ramil.myoffice.izhnet.ru
Browse files

Fix for bug #35732: read-only blocks SELECT statements in InnoDB 

Problem: SELECTs prohibited for a transactional SE in autocommit mode
if read_only is set.

Fix: allow them.
parent 5d725bfd

mysql-test/r/read_only_innodb.result

+30 −0
Original line number Diff line number Diff line
@@ -16,3 +16,33 @@ ERROR HY000: The MySQL server is running with the --read-only option so it canno 
set global read_only=0;

drop table table_11733 ;

drop user test@localhost;

GRANT CREATE, SELECT, DROP ON *.* TO test@localhost;

CREATE TABLE t1(a INT) ENGINE=INNODB;

INSERT INTO t1 VALUES (0), (1);

SET GLOBAL read_only=1;

SELECT * FROM t1;

a

0

1

BEGIN;

SELECT * FROM t1;

a

0

1

COMMIT;

SET GLOBAL read_only=0;

FLUSH TABLES WITH READ LOCK;

SELECT * FROM t1;

a

0

1

BEGIN;

SELECT * FROM t1;

a

0

1

COMMIT;

UNLOCK TABLES;

DROP TABLE t1;

DROP USER test@localhost;

echo End of 5.1 tests

mysql-test/t/read_only_innodb.test

+42 −0
Original line number Diff line number Diff line
@@ -41,3 +41,45 @@ set global read_only=0; 
drop table table_11733 ;

drop user test@localhost;



disconnect con1;



#

# Bug #35732: read-only blocks SELECT statements in InnoDB

#

# Test 1: read only mode

GRANT CREATE, SELECT, DROP ON *.* TO test@localhost;

connect(con1, localhost, test, , test);



connection default;

CREATE TABLE t1(a INT) ENGINE=INNODB;

INSERT INTO t1 VALUES (0), (1);

SET GLOBAL read_only=1;



connection con1;

SELECT * FROM t1;

BEGIN;

SELECT * FROM t1;

COMMIT;



connection default;

SET GLOBAL read_only=0;



#

# Test 2: global read lock

#

FLUSH TABLES WITH READ LOCK;



connection con1;

SELECT * FROM t1;

BEGIN;

SELECT * FROM t1;

COMMIT;



connection default;

UNLOCK TABLES;

DROP TABLE t1;

DROP USER test@localhost;



disconnect con1;



--echo echo End of 5.1 tests

sql/handler.cc

+33 −25
Original line number Diff line number Diff line
@@ -953,15 +953,20 @@ int ha_prepare(THD *thd) 
  As a side effect, propagates the read-only/read-write flags

  of the statement transaction to its enclosing normal transaction.

  

  @retval TRUE   we must run a two-phase commit. Returned

                 if we have at least two engines with read-write changes.

  @retval FALSE  Don't need two-phase commit. Even if we have two

                 transactional engines, we can run two independent

                 commits if changes in one of the engines are read-only.

  If we have at least two engines with read-write changes we must

  run a two-phase commit. Otherwise we can run several independent

  commits as the only transactional engine has read-write changes

  and others are read-only.



  @retval   0   All engines are read-only.

  @retval   1   We have the only engine with read-write changes.

  @retval   >1  More than one engine have read-write changes.

                Note: return value might NOT be the exact number of

                engines with read-write changes.

*/



static

bool

uint

ha_check_and_coalesce_trx_read_only(THD *thd, Ha_trx_info *ha_list,

                                    bool all)

{
@@ -998,7 +1003,7 @@ ha_check_and_coalesce_trx_read_only(THD *thd, Ha_trx_info *ha_list, 
      break;

    }

  }

  return rw_ha_count > 1;

  return rw_ha_count;

}
@@ -1061,19 +1066,30 @@ int ha_commit_trans(THD *thd, bool all) 
#ifdef USING_TRANSACTIONS

  if (ha_info)

  {

    bool must_2pc;

    uint rw_ha_count;

    bool rw_trans;



    DBUG_EXECUTE_IF("crash_commit_before", abort(););



    /* Close all cursors that can not survive COMMIT */

    if (is_real_trans)                          /* not a statement commit */

      thd->stmt_map.close_transient_cursors();



    rw_ha_count= ha_check_and_coalesce_trx_read_only(thd, ha_info, all);

    /* rw_trans is TRUE when we in a transaction changing data */

    rw_trans= is_real_trans && (rw_ha_count > 0);



    if (is_real_trans && wait_if_global_read_lock(thd, 0, 0))

    if (rw_trans &&

        wait_if_global_read_lock(thd, 0, 0))

    {

      ha_rollback_trans(thd, all);

      DBUG_RETURN(1);

    }



    if (   is_real_trans

        && opt_readonly

        && ! (thd->security_ctx->master_access & SUPER_ACL)

        && ! thd->slave_thread

       )

    if (rw_trans &&

        opt_readonly &&

        !(thd->security_ctx->master_access & SUPER_ACL) &&

        !thd->slave_thread)

    {

      my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only");

      ha_rollback_trans(thd, all);
@@ -1081,15 +1097,7 @@ int ha_commit_trans(THD *thd, bool all) 
      goto end;

    }



    DBUG_EXECUTE_IF("crash_commit_before", abort(););



    /* Close all cursors that can not survive COMMIT */

    if (is_real_trans)                          /* not a statement commit */

      thd->stmt_map.close_transient_cursors();



    must_2pc= ha_check_and_coalesce_trx_read_only(thd, ha_info, all);



    if (!trans->no_2pc && must_2pc)

    if (!trans->no_2pc && (rw_ha_count > 1))

    {

      for (; ha_info && !error; ha_info= ha_info->next())

      {
@@ -1129,7 +1137,7 @@ int ha_commit_trans(THD *thd, bool all) 
      tc_log->unlog(cookie, xid);

    DBUG_EXECUTE_IF("crash_commit_after", abort(););

end:

    if (is_real_trans)

    if (rw_trans)

      start_waiting_global_read_lock(thd);

  }

#endif /* USING_TRANSACTIONS */

sql/lock.cc

+1 −0
Original line number Diff line number Diff line
@@ -1533,6 +1533,7 @@ void start_waiting_global_read_lock(THD *thd) 
  if (unlikely(thd->global_read_lock))

    DBUG_VOID_RETURN;

  (void) pthread_mutex_lock(&LOCK_global_read_lock);

  DBUG_ASSERT(protect_against_global_read_lock);

  tmp= (!--protect_against_global_read_lock &&

        (waiting_for_read_lock || global_read_lock_blocks_commit));

  (void) pthread_mutex_unlock(&LOCK_global_read_lock);