Hi! On Thu, Apr 16, 2020 at 1:17 PM Sergei Golubchik wrote:

Hi, Michael!

On Apr 13, Michael Widenius wrote:

...

revision-id: 3cbe15bd78c (mariadb-10.5.2-120-g3cbe15bd78c) parent(s): d4d332d196d author: Michael Widenius committer: Michael Widenius timestamp: 2020-04-09 01:37:01 +0300 message:

Fixed core dump in alter table if ADD PARTITION fails

I didn't add a test case as to reproduce this we need to have a failed write in on of the engines. Bug found and bug fix verified while debugging S3 and partitions.

--- sql/sql_partition.cc | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc index ef8ef5114a8..4e984fa775d 100644 --- a/sql/sql_partition.cc +++ b/sql/sql_partition.cc @@ -6817,7 +6817,8 @@ static void handle_alter_part_error(ALTER_PARTITION_PARAM_TYPE *lpt, DBUG_ENTER("handle_alter_part_error"); DBUG_ASSERT(table->m_needs_reopen);

- if (close_table) + /* The table may not be open if ha_partition::change_partitions() failed */ + if (close_table && !table->file->is_open())

This looks *very* confusing, like you close the table only if it's *not* open. But then the whole if() is very confusing, as it closes in both branches, so the meaning of "close_table" is totally not clear.

Agree it looks confusing but I am reasonable sure it did stop a crash. I can't verify that as it was very hard to repeat.

May be instead of this your fix you'd better cherry-pick 9c02b7d6670b069866 from MySQL? It removes close_table completely, so I expect it to work for S3 just as you wanted.

I ported the above to MariaDB and I agree it looks this is a better solution. Regards, Monty