1. dbug state is now local to a thread
2. new macros: DBUG_EXPLAIN, DBUG_EXPLAIN_INITIAL,
DBUG_SET, DBUG_SET_INITIAL, DBUG_EVALUATE, DBUG_EVALUATE_IF
3. macros are do{}while(0) wrapped
4. incremental modifications to the dbug state (e.g. "+d,info:-t")
5. dbug code cleanup, style fixes
6. _db_on_ and DEBUGGER_ON/OFF removed
7. rest of MySQL code fixed because of 3 (missing ;) and 6
8. dbug manual updated
9. server variable @@debug (global and local) to control dbug from SQL!
a. -#T to print timestamps in the log
and possibly server crash in mysqld v5.0.
Reported MyISAM table was created in mysqld 4.1 and contains varchar field.
When binary files of that table was moved to 5.0, mysqld treats that varchar
field as a string field.
In order to make grouping server calculates group buffer, and because
that field is string server assumes it has fixed length and doesn't add
space for length, but later that field is converted to varchar field.
Due to this, when field values were actually copied, additional space for
length bytes is taken and buffer overrun occurs, which may lead to server crash.
The calc_group_buffer() function now reserves additional space for length
bytes for VAR_STRING fields, like for VARCHAR fields.
When an ambiguous field name is used in a group by clause a warning is issued
in the find_order_in_list function by a call to push_warning_printf.
An expression that was not always valid was passed to this call as the field
name parameter.
A query with a group by and having clauses could return a wrong
result set if the having condition contained a constant conjunct
evaluated to FALSE.
It happened because the pushdown condition for table with
grouping columns lost its constant conjuncts.
Pushdown conditions are always built by the function make_cond_for_table
that ignores constant conjuncts. This is apparently not correct when
constant false conjuncts are present.
The problem has manifested itself in the cases when we have a nested outer join
for which it can be inferred that one of the inner tables is a single row table.
functions are involved.
When subselect is a join with set functions and no record have been found in
it, end_send_group() sets null_row for all tables in order aggregate functions
to calculate their values correctly. Normally this null_row flag is cleared for
each table in sub_select(), but flush_cached_records() doesn't do so.
Due to this all fields from the table processed by flush_cached_records() are
always evaluated as nulls and whole select produces wrong result.
flush_cached_records() now clears null_row flag at the very beginning.
Remove wrong fix for Bug#14397 - OPTIMIZE TABLE with an open HANDLER causes a crash
Safety fix for bug #13855 "select distinct with group by caused server crash"
- Fixed tests
- Optimized new code
- Fixed some unlikely core dumps
- Better bug fixes for:
- #14397 - OPTIMIZE TABLE with an open HANDLER causes a crash
- #14850 (ERROR 1062 when a quering a view using a Group By on a column that can be null
- post-...-post review fixes
- Added "integer range walking" that allows to do partition pruning for "a <=? t.field <=? b"
by finding used partitions for a, a+1, a+2, ..., b-1, b.
