Hi Varun, On Sat, Mar 24, 2018 at 03:31:59AM +0530, Varun wrote:

revision-id: b718e87caaf2d0a60c19cd042dfc04868f4bb0b4 (mariadb-5.5.56-187-gb718e87caaf) parent(s): dfc79ae949f6d831ff65a08a5d32d14b59ba06e6 author: Varun Gupta committer: Varun Gupta timestamp: 2018-03-24 03:31:18 +0530 message:

MDEV-11274: Executing EXPLAIN of complex query over join limit causes server to crash

For this case we have a view that is mergeable but we are not able to merge it in the parent select because that would exceed the maximum tables allowed in the join list, so we materialise this view TABLE_LIST::dervied is NULL for such views, it is only set for views which have ALGORITHM=TEMPTABLE Fixed by making sure TABLE_LIST::derived is set for views that could not be merged

--- mysql-test/r/view.result | 197 +++++++++++++++++++++++++++++++++++++++++++++++ mysql-test/t/view.test | 196 ++++++++++++++++++++++++++++++++++++++++++++++ sql/table.h | 2 + 3 files changed, 395 insertions(+)

diff --git a/sql/table.h b/sql/table.h index 98f8c7ad73f..7b58f62e659 100644 --- a/sql/table.h +++ b/sql/table.h @@ -46,6 +46,7 @@ struct TABLE_LIST; class ACL_internal_schema_access; class ACL_internal_table_access; class Field; +struct LEX;

/* Used to identify NESTED_JOIN structures within a join (applicable only to

What is the above needed for? Please remove this change. Ok to push after this is addressed.

@@ -2125,6 +2126,7 @@ struct TABLE_LIST DBUG_PRINT("enter", ("Alias: '%s' Unit: %p", (alias ? alias : "<NULL>"), get_unit())); + derived= get_unit(); derived_type= ((derived_type & (derived ? DTYPE_MASK : DTYPE_VIEW)) | DTYPE_TABLE | DTYPE_MATERIALIZE); set_check_materialized();

BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog