result max length changed for the 'decimal' fields
so test results have to be fixed

my_decimal in some cases can contain more decimal digits than
is officially supported (DECIMAL_MAX_PRECISION), so we need to
prepare bigger buffer for the resulting string.

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  sergbook.mysql.com:/usr/home/serg/Abk/mysql-5.0

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/d2/hf/mrg/mysql-4.1-opt

into  moonbone.local:/mnt/gentoo64/work/28261-bug-5.0-opt-mysql

into  olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug28337

is involved.

The Arg_comparator::compare_datetime() comparator caches its arguments if
they are constants i.e. const_item() returns true. The
Item_func_get_user_var::const_item() returns true or false based on
the current query_id and the query_id where the variable was created.
Thus even if a query can change its value its const_item() still will return
true. All this leads to a wrong comparison result when an object of the
Item_func_get_user_var class is involved.

Now the Arg_comparator::can_compare_as_dates() and the
get_datetime_value() functions never cache result of the GET_USER_VAR()
function (the Item_func_get_user_var class).

subqueries in WHERE conditions.
This bug was introduced by the patch for bug 27321.

into  trift2.:/MySQL/M50/push-5.0

into  trift2.:/MySQL/M50/push-5.0

into  mysql.com:/home/hf/work/8663/my50-8663

into  mysql.com:/home/hf/work/8663/my50-8663

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-4.1-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build-work

into  adventure.(none):/home/thek/Development/cpp/mysql-5.0-runtime

 - Problem was reported as a SP variable using itself as 
   right value inside SUBSTR caused corruption of data. 
 - This bug could not be verified in either 5.0bk or 5.1bk
 - Added test case to prevent future regressions.

into  linux-st28.site:/home/martin/mysql/src/5.0o-bug27573

into  vajra.(none):/opt/local/work/mysql-5.0-21483

Bug#21483 "Server abort or deadlock on INSERT DELAYED with another
implicit insert"
Also fixes and adds test cases for bugs:
20497 "Trigger with INSERT DELAYED causes Error 1165"
21714 "Wrong NEW.value and server abort on INSERT DELAYED to a
table with a trigger".
Post-review fixes.

Problem:
In MySQL INSERT DELAYED is a way to pipe all inserts into a
given table through a dedicated thread. This is necessary for
simplistic storage engines like MyISAM, which do not have internal
concurrency control or threading and thus can not
achieve efficient INSERT throughput without support from SQL layer.
DELAYED INSERT works as follows:
For every distinct table, which can accept DELAYED inserts and has
pending data to insert, a dedicated thread is created to write data
to disk. All user connection threads that attempt to
delayed-insert into this table interact with the dedicated thread in
producer/consumer fashion: all records to-be inserted are pushed
into a queue of the dedicated thread, which fetches the records and 
writes them.
In this design, client connection threads never open or lock
the delayed insert table.
This functionality was introduced in version 3.23 and does not take 
into account existence of triggers, views, or pre-locking.
E.g. if INSERT DELAYED is called from a stored function, which,
in turn, is called from another stored function that uses the delayed
table, a deadlock can occur, because delayed locking by-passes
pre-locking. Besides:
 * the delayed thread works directly with the subject table through
   the storage engine API and does not invoke triggers
 * even if it was patched to invoke triggers, if triggers,
   in turn, used other tables, the delayed thread would
   have to open and lock involved tables (use pre-locking).
 * even if it was patched to use pre-locking, without deadlock
   detection the delayed thread could easily lock out user 
   connection threads in case when the same table is used both
   in a trigger and on the right side of the insert query: 
   the delayed thread would not release locks until all inserts 
   are complete, and user connection can not complete inserts 
   without having locks on the tables used on the right side of the
   query.

Solution:

These considerations suggest two general alternatives for the
future of INSERT DELAYED:
 * it is considered a full-fledged alternative to normal INSERT
 * it is regarded as an optimisation that is only relevant 
   for simplistic engines.
Since we missed our chance to provide complete support of new
features when 5.0 was in development, the first alternative
currently renders infeasible.
However, even the second alternative, which is to detect
new features and convert DELAYED insert into a normal insert, 
is not easy to implement.
The catch-22 is that we don't know if the subject table has triggers
or is a view before we open it, and we only open it in the
delayed thread. We don't know if the query involves pre-locking
until we have opened all tables, and we always first create
the delayed thread, and only then open the remaining tables.
This patch detects the problematic scenarios and converts
DELAYED INSERT to a normal INSERT using the following approach:
 * if the statement is executed under pre-locking (e.g. from
   within a stored function or trigger) or the right
   side may require pre-locking, we detect the situation
   before creating a delayed insert thread and convert the statement
   to a conventional INSERT.
  * if the subject table is a view or has triggers, we shutdown
   the delayed thread and convert the statement to a conventional
   INSERT.

in the case of the overflow in the decimal->integer conversion
we didn't return the proper boundary value, but just the result
of the conversion we calculated on the moment of the error

into  olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug28272

function.

A wrong  condition was used to check that the
Arg_comparator::can_compare_as_dates() function calculated the value of the
string constant. When comparing a non-const STRING function with a constant
DATETIME function it leads to saving an arbitrary value as a cached value of
the DATETIME function.

Now the Arg_comparator::set_cmp_func() function initializes the const_value
variable to the impossible DATETIME value (-1) and this const_value is
cached only if it was changed by the Arg_comparator::can_compare_as_dates()
function.

into  olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug28272

Several string comparisons could never yield true because they had an 'x' guard
added to the variable but not to the constant value. Fix that by guarding both sides.

to NULL

For queries of the form SELECT MIN(key_part_k) FROM t1 
WHERE key_part_1 = const and ... and key_part_k-1 = const,
the opt_sum_query optimization tries to
use an index to substitute MIN/MAX functions with their values according
to the following rules:
1) Insert the minimum non-null values where the WHERE clause still matches, or
3) A row of nulls

However, the correct semantics requires that there is a third case 2)
such that a NULL value is substituted if there are only NULL values for 
key_part_k.

The patch modifies opt_sum_query() to handle this missing case.

into  vajra.(none):/opt/local/work/mysql-5.0-runtime

into  vajra.(none):/opt/local/work/mysql-5.0-runtime

into  vajra.(none):/opt/local/work/mysql-4.1-runtime

for a query over an empty table right after its creation. 
The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
The added test case can reproduce the crash only with InnoDB tables and
only with 5.0.x.