Item_string::clone_item() creates a new Item_string that
points exactly to the same buffer that the original one does.
Later, Item_string::print() uses c_ptr() for the original Item_string,
which reallocs the original buffer, and the clone remain with
the old freed buffer.
Refactoring the code not to use c_ptr() in Item_string::print().
The crash was caused by range optimizer using RANGE_OPT_PARAM::min_key
(and max_key) to store keys. Buffer size was a good upper bound for
range analysis and partition pruning, but not for EITS selectivity
calculations.
Fixed by making these buffers variable-size. The sizes are calculated
from [pseudo]indexes used for range analysis.
1. Removing the legacy code that disabled equal field propagation in cases
when comparison is done as VARBINARY. This is now correctly handled by
the new propagation code in Item_xxx::propagate_equal_fields() and
Field_str::can_be_substituted_to_equal_item (the bug fix).
2. Also, removing legacy (pre-MySQL-4.1) Arg_comparator methods
compare_binary_string() and compare_e_binary_string(), as VARBINARY
comparison is correcty handled in compare_string() and compare_e_string() by
the corresponding VARBINARY collation handler implemented in my_charset_bin.
(not really a part of the bug fix)
WHERE COALESCE(time_column)=TIME('00:00:00')
AND COALESCE(time_column)=DATE('2015-09-11')
MDEV-8814 Wrong result for WHERE datetime_column > TIME('00:00:00')
ALTER TABLE should either bypass enforce-storage-engine, or mysql_upgrade
should refuse to run
Allow user to alter contents of existing table without enforcing
storage engine. However, enforce storage engine on ALTER TABLE
x ENGINE=y;
MDEV-8754 Wrong result for SELECT..WHERE year_field=2020 AND NULLIF(year_field,2010)='2020'
Problems:
1. Item_func_nullif stored a copy of args[0] in a private member m_args0_copy,
which was invisible for the inherited Item_func menthods, like
update_used_tables(). As a result, after equal field propagation
things like Item_func_nullif::const_item() could return wrong result
and a non-constant NULLIF() was erroneously treated as a constant
at optimize_cond() time.
Solution: removing m_args0_copy and storing the return value item
in args[2] instead.
2. Equal field propagation did not work well for Item_fun_nullif.
Solution: using ANY_SUBST for args[0] and args[1], as they are in
comparison, and IDENTITY_SUBST for args[2], as it's not in comparison.
1. use include/show_binlog_events.inc instead of SHOW BINLOG EVENTS
2. use include/show_relaylog_eventc.inc too
3. in all other places where a number might appear in the result
file, include binlog_start_pos.inc, calculate the position
like pos=`select $binlog_start_pos + 100`; and use
replace_result $pos <pos>
