The Item_outer_ref class based on the Item_direct_ref class was always used
to represent an outer field. But if the outer select is a grouping one and the
outer field isn't under an aggregate function which is aggregated in that
outer select an Item_ref object should be used to represent such a field.
If the outer select in which the outer field is resolved isn't grouping then
the Item_field class should be used to represent such a field.
This logic also should be used for an outer field resolved through its alias
name.
Now the Item_field::fix_outer_field() uses Item_outer_field objects to
represent aliased and non-aliased outer fields for grouping outer selects
only.
Now the fix_inner_refs() function chooses which class to use to access outer
field - the Item_ref or the Item_direct_ref. An object of the chosen class
substitutes the original field in the Item_outer_ref object.
The direct_ref and the found_in_select_list fields were added to the
Item_outer_ref class.
Geometry fields have a result type string and a
special subclass to cater for the differences
between them and the base class (just like
DATE/TIME).
When creating temporary tables for results of
functions that return results of type GEOMETRY
we must construct fields of the derived class
instead of the base class.
Fixed by creating a GEOMETRY field (Field_geom)
instead of a generic BLOB (Field_blob) in temp
tables for the results of GIS functions that
have GEOMETRY return type (Item_geometry_func).
This may lead to buffer overflow.
The String::qs_append() function will append a string
without checking if there's enough space.
So qs_append() must be called beforehand to ensure
there's enough space in the buffer for the subsequent
qs_append() calls.
Fixed Item_case_expr::print() to make sure there's
enough space before appending data by adding a call to
String::reserve() to make sure qs_append() will have
enough space.
Made year 2000 handling more uniform
Removed year 2000 handling out from calc_days()
The above removes some bugs in date/datetimes with year between 0 and 200
Now we get a note when we insert a datetime value into a date column
For default values to CREATE, don't give errors for warning level NOTE
Fixed some compiler failures
Added library ws2_32 for windows compilation (needed if we want to compile with IOCP support)
Removed duplicate typedef TIME and replaced it with MYSQL_TIME
Better (more complete) fix for: Bug#21103 "DATE column not compared as DATE"
Fixed properly Bug#18997 "DATE_ADD and DATE_SUB perform year2K autoconversion magic on 4-digit year value"
Fixed Bug#23093 "Implicit conversion of 9912101 to date does not match cast(9912101 as date)"
context was used as an argument of GROUP_CONCAT.
Ensured correct setting of the depended_from field in references
generated for set functions aggregated in outer selects.
A wrong value of this field resulted in wrong maps returned by
used_tables() for these references.
Made sure that a temporary table field is added for any set function
aggregated in outer context when creation of a temporary table is
needed to execute the inner subquery.
The problem in this bug is when we create temporary tables. When
temporary tables are created for unions, there is some
inferrence being carried out regarding the type of the column.
Whenever this column type is inferred to be REAL (i.e. FLOAT or
DOUBLE), MySQL will always try to maintain exact precision, and
if that is not possible (there are hardware limits, since FLOAT
and DOUBLE are stored as approximate values) will switch to
using approximate values. The problem here is that at this point
the information about number of significant digits is not
available. Furthermore, the number of significant digits should
be increased for the AVG function, however, this was not properly
handled. There are 4 parts to the problem:
#1: DOUBLE and FLOAT fields don't display their proper display
lengths in max_display_length(). This is hard-coded as 53 for
DOUBLE and 24 for FLOAT. Now changed to instead return the
field_length.
#2: Type holders for temporary tables do not preserve the
max_length of the Item's from which they are created, and is
instead reverted to the 53 and 24 from above. This causes
*all* fields to get non-fixed significant digits.
#3: AVG function does not update max_length (display length)
when updating number of decimals.
#4: The function that switches to non-fixed number of
significant digits should use DBL_DIG + 2 or FLT_DIG + 2 as
cut-off values (Since fixed precision does not use the 'e'
notation)
Of these points, #1 is the controversial one, but this
change is preferred and has been cleared with Monty. The
function causes quite a few unit tests to blow up and they had
to b changed, but each one is annotated and motivated. We
frequently see the magical 53 and 24 give way to more relevant
numbers.
after single-row table substitution could lead to a wrong result set.
The bug happened because the function Item_field::replace_equal_field
erroniously assumed that any field included in a multiple equality
with a constant has been already substituted for this constant.
This not true for fields becoming constant after row substitutions
for constant tables.
construct references invalid name.
Derived tables currently cannot use outer references.
Thus there is no outer context for them.
The 4.1 code takes this fact into account while the
Item_field::fix_outer_field code of 5.0 lost the check that blocks
any attempts to resolve names in outer context for derived tables.
can be specified
Currently MySQL allows one to specify what indexes to ignore during
join optimization. The scope of the current USE/FORCE/IGNORE INDEX
statement is only the FROM clause, while all other clauses are not
affected.
However, in certain cases, the optimizer
may incorrectly choose an index for sorting and/or grouping, and
produce an inefficient query plan.
This task provides the means to specify what indexes are
ignored/used for what operation in a more fine-grained manner, thus
making it possible to manually force a better plan. We do this
by extending the current IGNORE/USE/FORCE INDEX syntax to:
IGNORE/USE/FORCE INDEX [FOR {JOIN | ORDER | GROUP BY}]
so that:
- if no FOR is specified, the index hint will apply everywhere.
- if MySQL is started with the compatibility option --old_mode then
an index hint without a FOR clause works as in 5.0 (i.e, the
index will only be ignored for JOINs, but can still be used to
compute ORDER BY).
See the WL#3527 for further details.
The flag alias_name_used was not set on for the outer references
in subqueries. It resulted in replacement of any outer reference
resolved against an alias for a full field name when the frm
representation of a view with a subquery was generated.
If the subquery and the outer query referenced the same table in
their from lists this replacement effectively changed the meaning
of the view and led to wrong results for selects from this view.
Modified several functions to ensure setting the right value of
the alias_name_used flag for outer references resolved against
aliases.
Post fix for bug#23800.
The Item_field constructor now increases the select_n_where_fields counter.
sql_yacc.yy:
Post fix for bug#23800.
Take into account fields that might be added by subselects.
sql_lex.h:
Post fix for bug#23800.
Added the select_n_where_fields variable to the st_select_lex class.
sql_lex.cc:
Post fix for bug#23800.
Initialization of the select_n_where_fields variable.
Fixed compile-pentium64 scripts
Fixed wrong estimate of update_with_key_prefix in sql-bench
Merge bk-internal.mysql.com:/home/bk/mysql-5.1 into mysql.com:/home/my/mysql-5.1
Fixed unsafe define of uint4korr()
Fixed that --extern works with mysql-test-run.pl
Small trivial cleanups
This also fixes a bug in counting number of rows that are updated when we have many simultanous queries
Move all connection handling and command exectuion main loop from sql_parse.cc to sql_connection.cc
Split handle_one_connection() into reusable sub functions.
Split create_new_thread() into reusable sub functions.
Added thread_scheduler; Preliminary interface code for future thread_handling code.
Use 'my_thread_id' for internal thread id's
Make thr_alarm_kill() to depend on thread_id instead of thread
Make thr_abort_locks_for_thread() depend on thread_id instead of thread
In store_globals(), set my_thread_var->id to be thd->thread_id.
Use my_thread_var->id as basis for my_thread_name()
The above changes makes the connection we have between THD and threads more soft.
Added a lot of DBUG_PRINT() and DBUG_ASSERT() functions
Fixed compiler warnings
Fixed core dumps when running with --debug
Removed setting of signal masks (was never used)
Made event code call pthread_exit() (portability fix)
Fixed that event code doesn't call DBUG_xxx functions before my_thread_init() is called.
Made handling of thread_id and thd->variables.pseudo_thread_id uniform.
Removed one common 'not freed memory' warning from mysqltest
Fixed a couple of usage of not initialized warnings (unlikely cases)
Suppress compiler warnings from bdb and (for the moment) warnings from ndb
created for sorting.
Any outer reference in a subquery was represented by an Item_field object.
If the outer select employs a temporary table all such fields should be
replaced with fields from that temporary table in order to point to the
actual data. This replacement wasn't done and that resulted in a wrong
subquery evaluation and a wrong result of the whole query.
Now any outer field is represented by two objects - Item_field placed in the
outer select and Item_outer_ref in the subquery. Item_field object is
processed as a normal field and the reference to it is saved in the
ref_pointer_array. Thus the Item_outer_ref is always references the correct
field. The original field is substituted for a reference in the
Item_field::fix_outer_field() function.
New function called fix_inner_refs() is added to fix fields referenced from
inner selects and to fix references (Item_ref objects) to these fields.
The new Item_outer_ref class is a descendant of the Item_direct_ref class.
It additionally stores a reference to the original field and designed to
behave more like a field.
