maria-developers team mailing list archive

[Nirbhay Choubey <nirbhay@xxxxxxxxxxx>]

Hi Sachin!

On Fri, Jan 27, 2017 at 12:53 AM, SachinSetiya <sachin.setiya@xxxxxxxxxxx>
wrote:

> revision-id: d44c14e1e0dea312779ba0a8633583ee94284295
> (mariadb-10.1.21-2-gd44c14e)
> parent(s): a14638581b4c8ef175e68dccff07967d819b3b7e
> author: Sachin Setiya
> committer: Sachin Setiya
> timestamp: 2017-01-27 11:23:17 +0530
> message:
>
> MDEV-10812 WSREP causes responses being sent to protocol commands that
> must not send a response
>
> Problem:- When using wsrep (w/ galera) and issuing commands that can cause
> deadlocks, deadlock exception errors are sent in responses to commands
> such as close prepared statement and close connection which, by spec, must
> not send a
>

In commit message, we normally limit line width to 60 chars.


> response.
>
> Solution:- In dispatch_command, we will handle COM_QUIT and COM_STMT_CLOSE
> commands even in case of error.


I think you forgot to add the patch credit you had in previous commits.


>
---
>  mysql-test/suite/galera/r/galera_mdev_10812.result | 11 +++++++++
>  mysql-test/suite/galera/t/galera_mdev_10812.test   | 27
> ++++++++++++++++++++++
>  sql/sql_parse.cc                                   | 10 +++++++-
>  3 files changed, 47 insertions(+), 1 deletion(-)
>
> diff --git a/mysql-test/suite/galera/r/galera_mdev_10812.result
> b/mysql-test/suite/galera/r/galera_mdev_10812.result
> new file mode 100644
> index 0000000..fba1000
> --- /dev/null
> +++ b/mysql-test/suite/galera/r/galera_mdev_10812.result
> @@ -0,0 +1,11 @@
> +#
> +# MDEV-10812: On COM_STMT_CLOSE/COM_QUIT, when wsrep_conflict_state
> +# is ABORTED, it causes wrong response to be sent to the client
> +#
> +SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
> +CREATE TABLE t1(a INT PRIMARY KEY);
> +INSERT INTO t1 VALUES(1),(2),(3);
> +START TRANSACTION ;
> +UPDATE t1 SET a=a+100;
> +UPDATE t1 SET a=a+100;
> +DROP TABLE t1;
> diff --git a/mysql-test/suite/galera/t/galera_mdev_10812.test
> b/mysql-test/suite/galera/t/galera_mdev_10812.test
> new file mode 100644
> index 0000000..4539ab6
> --- /dev/null
> +++ b/mysql-test/suite/galera/t/galera_mdev_10812.test
> @@ -0,0 +1,27 @@
> +--source include/galera_cluster.inc
> +--source include/have_innodb.inc
> +
> +--echo #
> +--echo # MDEV-10812: On COM_STMT_CLOSE/COM_QUIT, when wsrep_conflict_state
> +--echo # is ABORTED, it causes wrong response to be sent to the client
> +--echo #
> +
> +#  First create a deadlock
> +--connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1
> +SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
> +CREATE TABLE t1(a INT PRIMARY KEY);
> +INSERT INTO t1 VALUES(1),(2),(3);
> +START TRANSACTION ;
> +UPDATE t1 SET a=a+100;
> +
> +--sleep 2
> +--connection node_2
> +UPDATE t1 SET a=a+100;
> +
> +--sleep 2
> +--connection node_1a
> +# here we get deadlock error
> +--disconnect node_1a
> +
> +--connection node_2
> +DROP TABLE t1;
> diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
> index 033e88a..cb0bd41 100644
> --- a/sql/sql_parse.cc
> +++ b/sql/sql_parse.cc
> @@ -1265,7 +1265,9 @@ bool dispatch_command(enum enum_server_command
> command, THD *thd,
>      {
>        wsrep_client_rollback(thd);
>      }
> -    if (thd->wsrep_conflict_state== ABORTED)
> +    /* We let COM_QUIT and COM_STMT_CLOSE to execute even if wsrep
> aborted. */
> +    if (thd->wsrep_conflict_state == ABORTED &&
> +        command != COM_STMT_CLOSE && command != COM_QUIT)
>      {
>        my_error(ER_LOCK_DEADLOCK, MYF(0), "wsrep aborted transaction");
>        WSREP_DEBUG("Deadlock error for: %s", thd->query());
> @@ -1918,6 +1920,12 @@ bool dispatch_command(enum enum_server_command
> command, THD *thd,
>
>    if (WSREP(thd))
>    {
> +    /*
> +      MDEV-10812
> +      In the case of COM_QUIT/COM_CLOSE thread status should be disabled.
>

s/COM_CLOSE/COM_STMT_CLOSE/


> +    */
> +    DBUG_ASSERT((command != COM_QUIT && command != COM_STMT_CLOSE)
> +                || thd->get_stmt_da()->is_disabled());
>

Could you check the indentation of the above line?

Considering above changes, I have no more suggestions. Ok to push.

Best,
Nirbhay


>      /* wsrep BF abort in query exec phase */
>      mysql_mutex_lock(&thd->LOCK_wsrep_thd);
>      do_end_of_statement= thd->wsrep_conflict_state != REPLAYING &&
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