The problem lies in how CURRENT_ROLE is defined. The
Item_func_current_role inherits from Item_func_sysconst, which defines
a safe_charset_converter to be a const_charset_converter.
During view creation, if there is no role previously set, the current_role()
function returns NULL.
This is captured on item instantiation and the
const_charset_converter call subsequently returns an Item_null.
In turn, the function is replaced with Item_null and the view is
then created with an Item_null instead of Item_func_current_role.
Without this patch, the first SHOW CREATE VIEW from the testcase would
have a where clause of WHERE role_name = NULL, while the second SHOW
CREATE VIEW would show a correctly created view.
The same applies for the DATABASE function, as it can change as well.
There is an additional problem with CURRENT_ROLE() when used in a
prepared statement. During prepared statement creation we used to set
the string_value of the function to the current role as well as the
null_value flag. During execution, if CURRENT_ROLE was not null, the
null_value flag was never set to not-null during fix_fields.
Item_func_current_user however can never be NULL so it did not show this
problem in a view before. At the same time, the CURRENT_USER() can not
be changed between prepared statement execution and creation so the
implementation where the value is stored during fix_fields is
sufficient.
Note also that DATABASE() function behaves differently during prepared
statements. See bug 25843 for details or commit
7e0ad09edf
An attempt to mark reference as dependent lead to transfering this property to
original view field and through it to other references of this field which
can't be dependent.
The function mysql_derived_merge() erroneously did not mark newly formed
AND formulas in ON conditions with the flag abort_on_null. As a result
not_null_tables() calculated incorrectly for these conditions. This
could prevent conversion of embedded outer joins into inner joins.
Changed a test case from table_elim.test to preserve the former execution
plan.
find_item_in_list() now recognize view fields like a fields even if they rever to an expression.
The problem of schema name do not taken into account for field with it and
derived table fixed.
Duplicating code removed
THD::>save_prep_leaf_list was set to true by multi-table update
statements with mergeable selects and never reset.
Make every statement reset it at start.
IS REJECTED.
Analysis
========
View creation with named columns over UNION is rejected.
Consider the following view definition:
CREATE VIEW v1 (fld1, fld2) AS SELECT 1 AS a, 2 AS b
UNION ALL SELECT 1 AS a, 1 AS a;
A 'duplicate column' error was reported due to the duplicate
alias name in the secondary SELECT. The VIEW column names
are either explicitly specified or determined from the
first SELECT (which can be auto generated if not specified).
Since a duplicate column name check was performed even
for the secondary SELECTs, an error was reported.
Fix
====
Check for duplicate column names only for the named
columns if specified or only for the first SELECT.
Do not use merge_for_insert for commands which use SELECT because optimizer can't work with such tables.
Fixes which makes multi-delete working with normally merged views.
~40% bugfixed(*) applied
~40$ bugfixed reverted (incorrect or we're not buggy)
~20% bugfixed applied, despite us being not buggy
(*) only changes in the server code, e.g. not cmakefiles
It is triple bug with one test suite:
1. Incorrect outer table detection
2. Incorrect leaf table processing for multi-update (should be full like for usual updates and inserts)
3. ON condition fix_fields() fould be called for all tables of the query.
- MDEV-5587 Server crashes in Locked_tables_list::restore_lock on CREATE OR REPLACE .. SELECT under LOCK
- MDEV-5586 Assertion `share->tdc.all_tables.is_empty() || remove_type != TDC_RT_REMOVE_ALL' fails in tdc_remove_table
- MDEV-5588 Strange error on CREATE OR REPLACE table over an existing view
mysql-test/r/create_or_replace.result:
Added test cases
mysql-test/r/lowercase_view.result:
New error message
mysql-test/r/merge.result:
New error message
mysql-test/r/multi_update.result:
New error message
mysql-test/r/subselect.result:
New error message
mysql-test/r/subselect_exists_to_in.result:
New error message
mysql-test/r/subselect_no_mat.result:
New error message
mysql-test/r/subselect_no_opts.result:
New error message
mysql-test/r/subselect_no_scache.result:
New error message
mysql-test/r/subselect_no_semijoin.result:
New error message
mysql-test/r/view.result:
New error message
mysql-test/suite/funcs_1/r/myisam_views-big.result:
New error message
mysql-test/t/create_or_replace.test:
New tests
mysql-test/t/view.test:
New error message
sql/share/errmsg-utf8.txt:
Added new error message
sql/sql_base.cc:
Updated error message
Do an automatic UNLOCK TABLES if we don't have any locked tables (safety fix)
sql/sql_db.cc:
Updated arguments
sql/sql_load.cc:
New error message
sql/sql_parse.cc:
Check that we are not using a table we are dropping and re-creating
sql/sql_table.cc:
Added parameter to mysql_rm_table_no_locks() to not automaticly do UNLOCK TABLES
Added better error message if trying to drop a view with DROP TABLE
Don't try to create something we select from
sql/sql_table.h:
Updated prototypes
