This is a performance bug, related to the parsing or 'OR' and 'AND' boolean
expressions.

Let N be the number of expressions involved in a OR (respectively AND).

When N=1

For example, "select 1" involve only 1 term: there is no OR operator.

In 4.0 and 4.1, parsing expressions not involving OR had no overhead.
In 5.0, parsing adds some overhead, with Select->expr_list.

With this patch, the overhead introduced in 5.0 has been removed,
so that performances for N=1 should be identical to the 4.0 performances,
which are optimal (there is no code executed at all)

The overhead in 5.0 was in fact affecting significantly some operations.
For example, loading 1 Million rows into a table with INSERTs,
for a table that has 100 columns, leads to parsing 100 Millions of
expressions, which means that the overhead related to Select->expr_list
is executed 100 Million times ...

Considering that N=1 is by far the most probable expression,
this case should be optimal.

When N=2

For example, "select a OR b" involves 2 terms in the OR operator.

In 4.0 and 4.1, parsing expressions involving 2 terms created 1 Item_cond_or
node, which is the expected result.
In 5.0, parsing these expression also produced 1 node, but with some extra
overhead related to Select->expr_list : creating 1 list in Select->expr_list
and another in Item_cond::list is inefficient.

With this patch, the overhead introduced in 5.0 has been removed
so that performances for N=2 should be identical to the 4.0 performances.
Note that the memory allocation uses the new (thd->mem_root) syntax
directly.
The cost of "is_cond_or" is estimated to be neglectable: the real problem
of the performance degradation comes from unneeded memory allocations.

When N>=3

For example, "select a OR b OR c ...", which involves 3 or more terms.

In 4.0 and 4.1, the parser had no significant cost overhead, but produced
an Item tree which is difficult to evaluate / optimize during runtime.
In 5.0, the parser produces a better Item tree, using the Item_cond
constructor that accepts a list of children directly, but at an extra cost
related to Select->expr_list.

With this patch, the code is implemented to take the best of the two
implementations:
- there is no overhead with Select->expr_list
- the Item tree generated is optimized and flattened.

This is achieved by adding children nodes into the Item tree directly,
with Item_cond::add(), which avoids the need for temporary lists and memory
allocation

Note that this patch also provide an extra optimization, that the previous
code in 5.0 did not provide: expressions are flattened in the Item tree,
based on what the expression already parsed is, and not based on the order
in which rules are reduced.

For example : "(a OR b) OR c", "a OR (b OR c)" would both be represented
with 2 Item_cond_or nodes before this patch, and with 1 node only with this
patch. The logic used is based on the mathematical properties of the OR
operator (it's associative), and produces a simpler tree.

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

VIEW".

mysql_list_fields() C API function would incorrectly set MYSQL_FIELD::decimals
member for some view columns.

The problem was in an incomplete implementation of 
Item_ident_for_show::make_field(), which is responsible for view
columns metadata.

statement being KILLed".

When statement which was trying to obtain write lock on then table and
which was blocked by existing read lock was killed, concurrent statements
that were trying to obtain read locks on the same table and that were
blocked by the presence of this pending write lock were not woken up and
had to wait until this first read lock goes away.

This problem was caused by the fact that we forgot to wake up threads
which pending requests could have been satisfied after removing lock
request for the killed thread.

The patch solves the problem by waking up those threads in such situation.

Test for this bug will be added to 5.1 only as it has much better
facilities for its implementation. Particularly, by using I_S.PROCESSLIST
and wait_condition.inc script we can wait until thread will be blocked on
certain table lock without relying on unconditional sleep (which usage
increases time needed for test runs and might cause spurious test
failures on slower platforms).

 error 1159 ' ' (fixed by the patch for Bug 25679)

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

- Removed unused variable.

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

When a table was explicitly locked with LOCK TABLES no associated
tables from any related trigger on the subject table were locked.
As a result of this the user could experience unexpected locking
behavior and statement failures similar to "failed: 1100: Table'xx'
was not locked with LOCK TABLES".

This patch fixes this problem by making sure triggers are
pre-loaded on any statement if the subject table was explicitly
locked with LOCK TABLES.

between perm and temp tables. Review fixes.

The original bug report complains that if we locked a temporary table
with LOCK TABLES statement, we would not leave LOCK TABLES mode
when this temporary table is dropped.

Additionally, the bug was escalated when it was discovered than
when a temporary transactional table that was previously
locked with LOCK TABLES statement was dropped, futher actions with
this table, such as UNLOCK TABLES, would lead to a crash.

The problem originates from incomplete support of transactional temporary
tables. When we added calls to handler::store_lock()/handler::external_lock()
to operations that work with such tables, we only covered the normal
server code flow and did not cover LOCK TABLES mode. 
In LOCK TABLES mode, ::external_lock(LOCK) would sometimes be called without
matching ::external_lock(UNLOCK), e.g. when a transactional temporary table
was dropped. Additionally, this table would be left in the list of LOCKed 
TABLES.

The patch aims to address this inadequacy. Now, whenever an instance
of 'handler' is destroyed, we assert that it was priorly
external_lock(UNLOCK)-ed. All the places that violate this assert
were fixed.

This patch introduces no changes in behavior -- the discrepancy in
behavior will be fixed when we start calling ::store_lock()/::external_lock()
for all tables, regardless whether they are transactional or not, 
temporary or not.

into  mysql.com:/home/svoj/devel/mysql/BUG29957/mysql-5.0-engines

INSERT/DELETE/UPDATE followed by ALTER TABLE within LOCK TABLES
may cause table corruption on Windows.

That happens because ALTER TABLE writes outdated shared state
info into index file.

Fixed by removing obsolete workaround.

Affects MyISAM tables on Windows only.

into  xiphis.org:/anubis/antony/work/mysql-5.0-engines.merge

into  gleb.loc:/home/uchum/work/bk/5.0-opt

  "Federated Denial of Service"
  Federated storage engine used to attempt to open connections within
  the ::create() and ::open() methods which are invoked while LOCK_open
  mutex is being held by mysqld. As a result, no other client sessions
  can open tables while Federated is attempting to open a connection.
  Long DNS lookup times would stall mysqld's operation and a rogue
  connection string which connects to a remote server which simply
  stalls during handshake can stall mysqld for a much longer period of
  time.
  This patch moves the opening of the connection much later, when the
  federated actually issues queries, by which time the LOCK_open mutex is
  no longer being held.

into  gleb.loc:/home/uchum/work/bk/5.0-opt

binary SHOW CREATE TABLE or SELECT FROM I_S.

The problem is that mysqldump generates incorrect dump for a table
with non-ASCII column name if the mysqldump's character set is
ASCII.

The fix is to:
  1. Switch character_set_client for the mysqldump's connection
  to binary before issuing SHOW CREATE TABLE statement in order
  to avoid conversion.
  
  2. Dump switch character_set_client statements to UTF8 and back
  for CREATE TABLE statement.

This allows 5.0 to work with 5.1 databases.

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-29959

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

---
fix compile on Windows for bug25714.c

When the SQL_BIG_RESULT flag is specified SELECT should store items from the
select list in the filesort data and use them when sending to a client.
The get_addon_fields function is responsible for creating necessary structures
for that. But this function was allowed to do so only for SELECT and
INSERT .. SELECT queries. This makes the SQL_BIG_RESULT useless for
the CREATE .. SELECT queries.

Now the get_addon_fields allows storing select list items in the filesort
data for the CREATE .. SELECT queries.

into  xiphis.org:/anubis/antony/work/p2-bug25714.1.merge-5.0

  "getGeneratedKeys() does not work with FEDERATED table"
  mysql_insert() expected the storage engine to update the row data
  during the write_row() operation with the value of the new auto-
  increment field. The field must be updated when only one row has
  been inserted as mysql_insert() would ignore the thd->last_insert.
  This patch implements HA_STATUS_AUTO support in ha_federated::info()
  and ensures that ha_federated::write_row() does update the row's
  auto-increment value.
  The test case was written in C as the protocol's 'id' value is
  accessible through libmysqlclient and not via SQL statements.
  mysql-test-run.pl was extended to enable running the test binary.

In sql/sql_yacc.yy, use the %prec construct at the end of rule join_table

into  magare.gmz:/home/kgeorge/mysql/autopush/B29644-5.0-opt

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

  Limit the fix for bug 28591 to InnoDB only

If a primary key is defined over column c of enum type then 
the EXPLAIN command for a look-up query of the form
  SELECT * FROM t WHERE c=0
said that the query was with an impossible where condition though the
query correctly returned non-empty result set when the table indeed 
contained rows with error empty strings for column c. 

This kind of misbehavior was due to a bug in the function 
Field_enum::store(longlong,bool) that erroneously returned 1 if
the the value to be stored was equal to 0. 
Note that the method 
Field_enum::store(const char *from,uint length,CHARSET_INFO *cs)
correctly returned 0 if a value of the error empty string 
was stored. 

into  chilla.local:/home/mydev/mysql-5.0-axmrg

into  magare.gmz:/home/kgeorge/mysql/autopush/B28951-5.0-opt

into  mysql.com:/home/hf/work/29494/my41-29494

into  mysql.com:/home/hf/work/29494/my50-29494

into  mysql.com:/home/hf/work/29494/my50-29494

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

into  gleb.loc:/home/uchum/work/bk/5.0-opt