SELECT statement itself returns empty.

As a result of this bug 'SELECT AGGREGATE_FUNCTION(fld) ... GROUP BY'
can return one row instead of an empty result set.

When GROUP BY only has fields of constant tables
(with a single row), the optimizer deletes the group_list.
After that we lose the information about whether we had an
GROUP BY statement. Though it's important
as SELECT min(x) from empty_table; and
   SELECT min(x) from empty_table GROUP BY y; have to return
different results - the first query should return one row,
second - an empty result set.
So here we add the 'group_optimized_away' flag to remember this case
when GROUP BY exists in the query and is removed
by the optimizer, and check this flag in end_send_group()

unpack_fields() didn't expect NULL_LENGHT in the field's descriptions.
In this case we get NULL in the resulting string so cannot use
strdup_root to make a copy of it.
strdup_root changed with strmake_root as it's NULL-safe

into  ramayana.hindu.god:/home/tsmith/m/bk/maint/41

into  sin.intern.azundris.com:/home/tnurnberg/27198/41-27198

into  chilla.local:/home/mydev/mysql-4.1-axmrg

gettimeofday() can fail and presumably, so can time().
Keep an eye on it.

Since we have no data on this at all so far, we just
retry on failure (and log the event), assuming that
this is just an intermittant failure. This might of
course hang the threat until we succeed. Once we know
more about these failures, an appropriate more clever
scheme may be picked (only try so many times per thread,
etc., if that fails, return last "good" time() we got or
some such).  Using sql_print_information() to log as this
probably only occurs in high load scenarios where the debug-
trace likely is disabled (or might interfere with testing
the effect).  No test-case as this is a non-deterministic
issue.

into  sita.local:/Users/tsmith/m/bk/maint/41

into  chilla.local:/home/mydev/mysql-4.1-axmrg

into  chilla.local:/home/mydev/mysql-4.1-axmrg

into  gleb.loc:/home/uchum/work/bk/4.1-opt

into  sita.local:/Users/tsmith/m/bk/maint/41

into  anubis.xiphis.org:/usr/home/antony/work/mysql-4.1-engines.merge

into  chilla.local:/home/mydev/mysql-4.1-axmrg

Dropping an user defined function may cause server crash in
case this function is still in use by another thread.

The problem was that our hash implementation didn't update
hash link list properly when hash_update() was called.

into  maint1.mysql.com:/data/localhome/tsmith/bk/maint/41

into  gleb.loc:/home/uchum/work/bk/4.1-opt

  Test case update for bug #29294.

  Windows compilation error fix.

The `SELECT 'r' INTO OUTFILE ... FIELDS ENCLOSED BY 'r' ' statement
encoded the 'r' string to a 4 byte string of value x'725c7272'
(sequence of 4 characters: r\rr).
The LOAD DATA statement decoded this string to a 1 byte string of
value x'0d' (ASCII Carriage Return character) instead of the original
'r' character.
The same error also happened with the FIELDS ENCLOSED BY clause
followed by special characters: 'n', 't', 'r', 'b', '0', 'Z' and 'N'.

NOTE 1: This is a result of the undocumented feature: the LOAD DATA INFILE
recognises 2-byte input sequences like \n, \t, \r and \Z in addition
to documented 2-byte sequences: \0 and \N. This feature should be
documented (here backspace character is a default ESCAPED BY character,
in the real-life example it may be any ESCAPED BY character).

NOTE 2, changed behaviour:
Now the `SELECT INTO OUTFILE' statement with the `FIELDS ENCLOSED BY'
clause followed by one of: 'n', 't', 'r', 'b', '0', 'Z' or 'N' characters
encodes this special character itself by doubling it ('r' --> 'rr'),
not by prepending it with an escape character.

Sometimes special 0 ENUM values was ALTERed to normal
empty string ENUM values.

Special 0 ENUM value has the same string representation
as normal ENUM value defined as '' (empty string).
The do_field_string function was used to convert
ENUM data at an ALTER TABLE request, but this
function doesn't care about numerical "indices" of
ENUM values, i.e. do_field_string doesn't distinguish
a special 0 value from an empty string value.

A new copy function called do_field_enum has been added to
copy special 0 ENUM values without conversion to an empty
string.

into  maint1.mysql.com:/data/localhome/tsmith/bk/maint/41

into  gleb.loc:/home/uchum/work/bk/4.1-opt

into  mysql.com:/home/ram/work/b29079/b29079.4.1

Problem: long and long long types mess in a comparison may lead to wrong results on some platforms.
Fix: prefer [unsigned] long long as [u]longlong as it's used unconditionally in many places.

into  magare.gmz:/home/kgeorge/mysql/autopush/B29116-4.1-opt

 counters from relay

Updated the test to return columns vertically.

into  pilot.(none):/data/msvensson/mysql/mysql-4.1-maint

 - Add test case for this already existing feature 

we use net->vio in my_net_local_init, but in the my_net_init
implementation we set it after the call, so work with unspecified
net->vio value

into  maint1.mysql.com:/data/localhome/tsmith/bk/maint/41

into  trift2.:/MySQL/M41/push-4.1

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

into  trift2.:/MySQL/M41/push-4.1

into  trift2.:/MySQL/M41/push-4.1

into  chilla.local:/home/mydev/mysql-4.1-axmrg

into  trift2.:/MySQL/M41/push-4.1

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

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