This is a backport of the patch for MDEV-9653 (fixed earlier in 10.1.13).
The code in Item_func_case::fix_length_and_dec() did not
calculate max_length and decimals properly.
In case of any numeric result (DECIMAL, REAL, INT) a generic method
Item_func_case::agg_num_lengths() was called, which could erroneously result
into a DECIMAL item with max_length==0 and decimals==0, so the constructor of
Field_new_decimals tried to create a field of DECIMAL(0,0) type,
which caused a crash.
Unlike Item_func_case, the code responsible for merging attributes in
Item_func_coalesce::fix_length_and_dec() works fine: it has specific execution
branches for all distinct numeric types and correctly creates a DECIMAL(1,0)
column instead of DECIMAL(0,0) for the same set of arguments.
The fix does the following:
- Moves the attribute merging code from Item_func_coalesce::fix_length_and_dec()
to a new method Item_func_hybrid_result_type::fix_attributes()
- Removes the wrong code from Item_func_case::fix_length_and_dec()
and reuses fix_attributes() in both Item_func_coalesce::fix_length_and_dec()
and Item_func_case::fix_length_and_dec()
- Fixes count_real_length() and count_decimal_length() to get an array
of Items as an argument, instead of using Item::args directly.
This is needed for Item_func_case::fix_length_and_dec().
- Moves methods Item_func::count_xxx_length() from "public" to "protected".
- Removes Item_func_case::agg_num_length(), as it's not used any more.
- Additionally removes Item_func_case::agg_str_length(),
as it also was not used (dead code).
SHOW PROCESSLIST output can be affected by not completed concurrent queries.
Removed this affected SHOW PROCESSLIST since it doesn't seem to affect original
problem.
Item_func_ifnull::date_op() and Item_func_coalesce::date_op() could
erroneously return 0000-00-00 instead of NULL when get_date()
was called with the TIME_FUZZY_DATES flag, e.g. from LEAST().
Problem was that created table was not marked as used (not set query_id) and so opening tables for stored function pick it up (as opened place holder for it) and used changing TABLE internals.
The select mentioned in the bug attempted to create a temporary table
using the maria storage engine. The table needs to have primary keys such that
duplicates can be removed. Unfortunately this use case has a longer
than allowed key and the tmp table got created without a temporary key.
We must not allow materialization for the subquery if the total key
length and key parts is greater than what the storage engine supports.
When one evaluates row-based comparison like (X, Y) = (A,B), one should
first call bring_value() for the Item that returns row value. If you
don't do that and just attempt to read values of X and Y, you get stale
values.
Semi-join/Materialization can take a row-based comparison apart and
make ref access from it. In that case, we need to call bring_value()
to get the index lookup components.
Consider a query with subquery in form t.key=(select ...). Suppose, the
parent query uses this equality for ref access.
It will attempt to evaluate the subquery in get_best_combination(),
right before the join->join_tab[...] array is filled. The problem was
that subquery optimization will attempt to look at parent's join->join_tab
to check how many times subquery will be executed (and crash).
Fixed by not doing that when the subquery is constant (non-constant
subqueries are only be evaluated during join execution, so they are not
affected)
UNIX_TIMESTAMP(STR_TO_DATE('201506', "%Y%M"
Issue:
-----
When an invalid date is supplied to the UNIX_TIMESTAMP
function from STR_TO_DATE, no check is performed before
converting it to a timestamp value.
SOLUTION:
---------
Add the check_date function and only if it succeeds,
proceed to the timestamp conversion.
No warning will be returned for dates having zero in
month/date, since partial dates are allowed. UNIX_TIMESTAMP
will return only a zero for such values.
The problem has been handled in 5.6+ with WL#946.
Item_func_coalesce::fix_length_and_dec() calls
Item_func::count_string_result_length()) which called agg_arg_charsets()
with wrong flags, so the collation derivation of the COALESCE result was
not properly set to DERIVATION_COERCIBLE. It erroneously stayed
DERIVATION_NUMERIC. So GREATEST() misinterpreted the argument as
a number rather that a string and did not calculate its own length properly.
mysqldump --routine fails to dump databases containing backslash ("\")
character. This happened because escaped database name was being used as an
identifier while changing current database. Such identifers are not supposed
to be escaped, they must be properly quoted instead.
DOING BAD DDL IN PREPARED STATEMENT
Analysis
========
A repeat execution of the prepared statement 'ALTER TABLE v1
CHECK PARTITION' where v1 is a view leads to server exit.
ALTER TABLE ... CHECK PARTITION is not applicable for views
and check for the same check is missing. This leads to
further execution and creation of derived table for the view
(Allocated under temp_table mem_root). Any reference to open
view or related pointers from second execution leads to
server exit as the same was freed at previous execution closure.
Fix:
======
Added check for view in mysql_admin_table() on PARTITION
operation. This will prevent mysql_admin_table() from
going ahead and creating temp table and related issues.
Changed message on admin table view operation error to
be more appropriate.
MDEV-8938 Server Crash on Update with joins
Make unique table check after setup_fields of update because unique table can materialize table and we do not need field resolving after materialization.
===========
When doing an upgrade, you execute mysql_upgrade. If
mysql_upgrade fails to connect or it connects with a user
without the proper privileges, it will return the error:
FATAL ERROR: Upgrade failed
which is not very informative.
ANALYSIS
========
In main() and check_version_match(), the condition for
errors are clubbed together and throw the same error msg.
The functions need to be splitted up and the corresponding
error msgs have to be displayed.
FIX
===
Splitted the functions and added the specific error msg.
Issue: main.events_1 will fail after 10-10-2015 due
to hardcoded dates specified with events.
Fix: Replace harcoded dates with current dates and offset.
IMPLEMENTED IN ALL CLIENT PROGRAMS
Description: Option "enable-cleartext-plugin" is not
available for the following client utilities:-
mysqldump
mysqlimport
mysqlshow
mysqlcheck
Analysis: The unavailability of this option limits the
features like PAM authentication from using the above
mentioned utilities.
Fix: Option "enable-cleartext-plugin" is implemented in the
above mentioned client utilities.
Issue:
======
The fulltext predicate is inside a subquery and involves
an outer reference; it thus cannot be used for FT index look-up,
but MySQL does not see it, which causes a illegal access.
Solution:
=========
Solution is backported from bug#21140088. Outer reference can
not be used as argument of the MATCH function. Added check for
outer reference.
When CHANGE MASTER was executed as a PS, its attributes were wrongly
getting reset toward the end of PREPARE. As a result, the subsequent
executions had no effect. Fixed by making sure that the CHANGE MASTER
attributes are preserved during the lifetime of the PS.
Problem was in rewriting left expression which had 2 references on it. Solved with making subselect reference main.
Item_in_optimized can have not Item_in_subselect reference in left part so type casting with no check is dangerous.
Item::cols() should be checked after Item::fix_fields().
FILE
PROBLEM
In 5.5 when doing doing a rename of a column ,we ignore the case between
old and new column names while comparing them,so if the change is just
the case then we don't even mark the field FIELD_IS_RENAMED ,we just update
the frm file ,but don't recreate the table as is the norm when alter is
used.This leads to inconsistency in the innodb data dictionary which causes
index creation to fail.
FIX
According to the documentation any innodb column rename should trigger
rebuild of the table. Therefore for innodb tables we will do a strcmp()
between the column names and if there is case change in column name
we will trigger a rebuild.
