Too restrictive assertion, can fail during purge

Regression from bug#14621190 due to disabled optimistic restoration
of cursor, which required full key lookup instead of verifying
if previously positioned btree cursor could be reused.

Fixed by enable optimistic restore and adjust cursor afterward.

rb#3324 approved by Marko.

Problem:
COM_CHANGE_USER allows brute-force attempts to crack a password at a very high
rate as it does not cause any significant delay after a login attempt has
failed. This issue was reproduced using John-The-Ripper password
cracking tool through which about 5000 passwords per second could be attempted.

Solution:
The non-GA version's solution was to disconnect the connection when a login
attempt failed. Now since our aim to to reduce the rate at which passwords 
are tested, we introduced a sleep(1) after every login attempt failed. This
significantly increased the delay with which the password was cracked.

Automerged from mysql-5.5 bug branch into latest mysql-5.5.

             AS A INNODB PARTITTION.
[Merged from 5.1]             

             AS A INNODB PARTITTION.

PROBLEM
-------
The correct engine_type was not being set during 
rebuild of the partition due to which the handler
was always created with the default engine,
which is innodb for 5.5+ ,therefore even if the
table was myisam, after rebuilding the partitions
ended up as innodb partitions.

FIX
---
Set the correct engine type during rebuild.  

[Approved by mattiasj #rb3599]

The assertion happens when: (i) the master and slave are configured to
use the semisync plugin; (ii) the DBA disables semisync on the master;
(iii) and he also unsets the option to wait for slaves ACK even if the
semisync slave count reaches 0 during the waiting period. This
combination of factors makes the server run into an assertion as soon
as the last semisync slave disconnects and its dump thread exits.
  
The root of the problem is the fact that when the dump thread
disconnects and calls the observer hook transmit_stop, which ends up
calling ReplSemiSyncMaster::remove_slave, there is no check whether
the master has already disabled semisync or not. If it has, the then a
second call to the switch_off member function must be avoided.
  
The quick fix is to avoid calling switch_off if the DBA has disabled
the semisync plugin interactively on the master. Also, the switch_off
member function should only be called if the plugin has not been
switched off already. This is basically the pattern throughout the
rest of the semisync plugin and no other calls seem vulnerable to
similar crashes/assertions.

(This a backport of the patch to 5.5, which is also vulnerable.)

--Implemented CHECK TABLE...QUICK.
  Introduce CHECK TABLE...QUICK that would skip the btr_validate_index()
  and btr_search_validate() call, and count the no. of records in each index.

Approved by Marko and Kevin. (rb#3567).

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Merging mysql-5.5 bug branch into latest mysql-5.5.

REPLICATION FILTERS ARE USED.
Merging fix from mysql-5.1

REPLICATION FILTERS ARE USED.

Problem:
When Filtered-slave applies Int_var_log_event and when it
tries to write the event to its own binlog, LAST_INSERT_ID
value is written wrongly.

Analysis:
THD::stmt_depends_on_first_successful_insert_id_in_prev_stmt
is a variable which is set when LAST_INSERT_ID() is used by
a statement. If it is set, first_successful_insert_id_in_
prev_stmt_for_binlog will be stored in the statement-based
binlog. This variable is CUMULATIVE along the execution of
a stored function or trigger: if one substatement sets it
to 1 it will stay 1 until the function/trigger ends,
thus making sure that first_successful_insert_id_in_
prev_stmt_for_binlog does not change anymore and is
propagated to the caller for binlogging. This is achieved
using the following code
if(!stmt_depends_on_first_successful_insert_id_in_prev_stmt)               
{                                                                           
  /* It's the first time we read it */                                      
  first_successful_insert_id_in_prev_stmt_for_binlog=                       
  first_successful_insert_id_in_prev_stmt;                                
  stmt_depends_on_first_successful_insert_id_in_prev_stmt= 1;               
}

Slave server, after receiving Int_var_log_event event from
master, it is setting
stmt_depends_on_first_successful_insert_id_in_prev_stmt
to true(*which is wrong*) and not setting
first_successful_insert_id_in_prev_stmt_for_binlog. Because
of this problem, when the actual DML statement with
LAST_INSERT_ID() is parsed by slave SQL thread,
first_successful_insert_id_in_prev_stmt_for_binlog is not
set. Hence the value zero (default value) is written to
slave's binlog.

Why only *Filtered slave* is effected when the code is
in common place:
-------------------------------------------------------
In Query_log_event::do_apply_event,
THD::stmt_depends_on_first_successful_insert_id_in_prev_stmt
is reset to zero at the end of the function. In case of
normal slave (No Filters), this variable will be reset. 
In Filtered slave, Slave SQL thread defers all IRU events's
execution until IRU's Query_log event is received. Once it
receives Query_log_event it executes all pending IRU events
and then it executes Query_log_event. Hence the variable is
not getting reset to 0, causing this bug.

Fix: As described above, the root cause was setting 
THD::stmt_depends_on_first_successful_insert_id_in_prev_stmt
when Int_var_log_event was executed by a SQL thread. Hence
removing the problematic line from the code.

Merging from mysql-5.1 to mysql-5.5

Description: Fix for bug CVE-2012-5611 (bug 67685) is 
incomplete. The ACL_KEY_LENGTH-sized buffers in acl_get() and 
check_grant_db() can be overflown by up to two bytes. That's 
probably not enough to do anything more serious than crashing 
mysqld.
Analysis: In acl_get() when "copy_length" is calculated it 
just adding the variable lengths. But when we are using them 
with strmov() we are adding +1 to each. This will lead to a 
three byte buffer overflow (i.e two +1's at strmov() and one 
byte for the null added by strmov() function). Similarly it 
happens for check_grant_db() function as well.
Fix: We need to add "+2" to "copy_length" in acl_get() 
and "+1" to "copy_length" in check_grant_db(). 

REPEATED TWICE IN BINLOG

Problem:
=======
If LOAD DATA ... SET ... is used the last argument of SET is
repeated twice in replication binlog.

Analysis:
========
LOAD DATA statements are reconstructed once again before
they are written to the binary log. When SET clauses are
specified as part of LOAD DATA statement, these SET clause
user command strings need to be stored in order to rebuild
the original user command. During parsing each column and
the value in the SET command are stored in two differenet
lists. All the values are stored in a string list.

When SET expression has more than one value as shown in the
following example:
SET a = @A, b = CONCAT(@b, '| 123456789');

Parser extracts values in the following manner i.e Item name
, value string, actual length of the value of the item with
in the string.

Item a:
Value for a:"= @A, b = CONCAT(@b, '| 123456789')
str_length = 4
Item b:
Value for b:"= CONCAT(@b, '| 123456789')
str_length = 27

During reconstructing the LOAD DATA command the above
strings are retrived as it is and appended to the LOAD DATA
statement. Hence it becomes as shown below.

SET `a`= @A, b = CONCAT(@b, '| 123456789'),
`b`= CONCAT(@b, '| 123456789')

Fix:
===
During reconstruction of SET command, retrieve exact item
value string rather than reading the entire string.

sql/sql_load.cc:
  Added code to extract the exact Item value.

Merge from mysql-5.1 into mysql-5.5.

WL#7266: Dump-thread additional concurrency tests                                                                                                                           

This worklog aims at testing the two following scenarios:

1) Whenever the mysql_binlog_send method (dump thread)
reaches the end of file when reading events from the binlog, before
checking if it should wait for more events, there was a test to
check if the file being read was still active, i.e, it was the last
known binlog. However, it was possible that something was written to
the binary log and then a rotation would happen, after EOF was
detected and before the check for active was performed. In this
case, the end of the binary log would not be read by the dump
thread, and this would cause the slave to lose updates.
This test verifies that the problem has been fixed. It waits during
this window while forcing a rotation in the binlog.

2) Verify dump thread can send events in active file, correctly after
encountering an IO error.

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               AND 'KILL SESSION' LEAD TO CRASH               

Analysis:
--------
This situation occurs when the connection executes query 
"show engine innodb status" and this connection is killed by
executing statement "kill <con>" by another connection.

In function "innodb_show_status", function "stat_print"
is called to print the status but return value of function
is not checked.  After killing connection, if write to 
connection fails then error is returned and same is set
in Diagnostic area. Since FALSE is returned from
"innodb_show_status" now, assert to check no error
is set in function "set_eof_status" (called from
my_eof) is failing. 

Fix:
----
Changed code to check return value of function "stat_print"
in "innodb_show_status".

ReplSemiSyncMaster::updateSyncHeader contains redundant assignments
to the local variable sync.

This patch removes them.

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ha_innobase::records_in_range() should return HA_POS_ERROR for the table during discarded without requesting pages.
The later other handler method should treat the error correctly.

Approved by Sunny in rb#3433

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Description:
------------
There are 2 issues reported in the bug report,

1. One session running a "long" select, then, from the other
session, you kill that first one, while select is
running, and it receives that message "Server shutdown in
progress".
Reported Date: 02-Apr-2006

=> Looks like this isuse is already fixed in 2009 by the patch
   pushed for bug28141. 

2. Killing query which goes to filesort, logs error entries like:

120416  9:17:28 [ERROR] mysqld: Sort aborted: Server shutdown in
                                              progress 
120416  9:18:48 [ERROR] mysqld: Sort aborted: Server shutdown in
                                              progress 
120416  9:19:39 [ERROR] mysqld: Sort aborted: Server shutdown in
                                              progress 
Reported Date: 16-Apr-2012                                              

=> This issue is introduced in 5.5+ versions. Fixing this issue
   in this patch.


Analysis:
---------
In function "filesort()", on error we are logging error message.
To the error message, the message related THD::killed_errno is
also appeneded, if it is set.(THD::kill_errno value is obtained
by calling member function THD::killed_errno)

In the scenario mentioned in this bug report, when we kill the
connection, THD::kill_errno is set to the THD::KILL_CONNECTION.
Enum type THD::KILL_CONNECTION corressponds to value 
ER_SERVER_SHUTDOWN. Because of this, "Server shutdown in ...." is
appended to the message logged.

Fix:
----
Modified code of "filesort()" function to append "KILL_QUERY"
status to error message when thread is killed and server
shutdown is not in progress.

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INDEX_READ_MAP HAD NO MATCH

If index_read_map is called for exact search and no matching records
exists it will position the cursor on the next record, but still having the
relative position to BTR_PCUR_ON.
This will make a call for index_next to read yet another next record,
instead of returning the record the cursor points to.

Fixed by setting pcur->rel_pos = BTR_PCUR_BEFORE if an exact
[prefix] search is done, but failed.

Also avoids optimistic restoration if rel_pos != BTR_PCUR_ON,
since btr_cur may be different than old_rec.

rb#3324, approved by Marko and Jimmy

As this mysql_install_db.pl file has always generated lots of confusion on Windows.  This fix will make sure to get it removed only from Windows

      Registry redirection was improper and hence not able to pick the value for the OLDERVERSION property. as a result in the install upgrade dialog null value wa being passed.

log_buffer_extend() should fill the new buffer with 0.