WITH COMPOSITE KEY COLUMNS

Problem:-
While running a SELECT query with several AGGR(DISTINCT) function 
and these are referring to different field of same composite key, 
Returned incorrect value.

Analysis:-

In a table, where we have composite key like (a,b,c)
and when we give a query like

select COUNT(DISTINCT b), SUM(DISTINCT a) from ....

here, we first make a list of items in Aggr(distinct) function
(which is a, b), where order of item doesn't matter. 
and then we see, whether we have a composite key where the prefix 
of index columns matches the items of the aggregation function.
(in this case we have a,b,c).

if yes, so we can use loose index scan and we need not perform 
duplicate removal to distinct in our aggregate function.

In our table, we traverse column marked with <-- and get the result as
(a,b,c)      count(distinct b)           sum(distinct a)
             treated as count b          treated as sum(a)
(1,1,2)<--              1                      1		
(1,2,2)<--              1++=2                  1+1=2
(1,2,3)		
(2,1,2)<--              2++=3                  1+1+2=4
(2,2,2)<--              3++=4                  1+1+2+2=6
(2,2,3)

result will be 4,6, but it should be (2,3)

As in this case, our assumption is incorrect. If we have
query like 
select count(distinct a,b), sum(distinct a,b)from ..
then we can use loose index scan

Solution:-
In our query, when we have more then one aggr(distinct) function 
then they should refer to same  fields like

select count(distinct a,b), sum(distinct a,b) from .. 

-->we can use loose scan index as both aggr(distinct) refer to same fields a,b.

If they are referring to different field like

select count(distinct a), sum(distinct b) from .. 

-->will not use loose scan index as both aggr(distinct) refer to different fields.

No commit message

innobase_convert_to_filename_charset() was by mistake kept within
the conditional compilation of UNIV_COMPILE_TEST_FUNCS.  Now placing
the function out of UNIV_COMPILE_TEST_FUNCS.  Also, removed the
unnecessary log message (as in 5.6+).

Reverting fix for Bug#16119355 in 5.1 as this needs two patches 
from 5.5+ to work for a certain case

is included only in the builtin InnoDB, and it is missed in InnoDB
plugin.  Adding this function in InnoDB plugin as well.

No commit message

              NUMBER ALREADY USED BY 5.6

The problem was that the patch for Bug#13004581 added a new error
message to 5.5. This causes it to use an error number already used
in 5.6 by ER_CANNOT_LOAD_FROM_TABLE_V2. Which means that error
message number stability between GA releases is broken.

This patch fixes the problem by removing the error message and
using ER_UNKNOWN_ERROR instead.

                           STRING CONVERSION FUNCTIONS
            
Problem:
While executing the prepared statement, user variable is
set to memory which would be freed at the end of
execution.
If the statement is executed again, valgrind throws
error when accessing this pointer.
            
Analysis:
            
1. First time when Item_func_set_user_var::check is called,
memory is allocated for "value" to store the result.
(In the call to copy_if_not_alloced).
2. While sending the result, Item_func_set_user_var::check
is called again. But, this time, its called with
"use_result_field" set to true. 
As a result, we call result_field->val_str(&value).
3. Here memory allocated for "value" gets freed. And "value"
gets set to "result_field", with "str_length" being that of
result_field's.
4. In the call to JOIN::cleanup, result_field's memory gets
freed as this is allocated in a chunk as part of the
temporary table which is needed to execute the query.
5. Next time, when execute of the same statement is called,
"value" will be set to memory which is already freed.
Valgrind error occurs as "str_length" is positive 
(set at Step 3)
            
Note that user variables list is stored as part of the Lex object
in set_var_list. Hence the persistance across executions.
      
Solution:
Patch for Bug#11764371 fixed in mysql-5.6+ fixes this problem 
as well.So backporting the same.
      
In the solution for Bug#11764371, we create another object of 
user_var and repoint it to temp_table's field. As a result while 
deleting the alloced buffer in Step 3, since the cloned object 
does not own the buffer, deletion will not happen.
So at step 5 when we execute the statement second time, the 
original object will be used and since deletion did not happen 
valgrind will not complain about dangling pointer.


sql/item_func.h:
  Add constructors.
sql/sql_select.cc:
  Change user variable assignment functions to read from fields after
  tables have been unlocked.

The problem happened due to broken left expression in Item_in_optimizer object.
In case of the bug left expression is runtime created Item_outer_ref item which
is deleted at the end of the statement and one of Item_in_optimizer arguments
becomes bad when re-executed. The fix is to use real_item() instead of original
left expression. Note: It feels a bit weird that after preparing, the field is
directly part of the generated Item_func_eq, whereas in execution it is replaced
with an Item_outer_ref wrapper object.


sql/item_subselect.cc:
  use left_expr->real_item() instead of original left expression
  because left_expr can be runtime created Ref item which is deleted
  at the end of the statement. Thus one of 'substitution' arguments
  can be broken in case of PS.

TRANSACTION ROLLBACK

Problem:
=======
"prepare_commit_mutex" is acquired during "innobase_xa_prepare"
and it is freed only in "innobase_commit". After prepare,
if the commit operation fails the transaction is rolled back
but the mutex is not released.

Analysis:
========
During transaction commit process transaction is prepared and
the "prepare_commit_mutex" is acquired to preserve the order
of commit. After prepare write to binlog is initiated.

File: sql/handler.cc
      if (error || (is_real_trans && xid &&
----->             (error= !(cookie= tc_log->log_xid(thd, xid)))))
      {
        ha_rollback_trans(thd, all);

In the above code "tc_log->log_xid" operation fails.

When the write to binlog fails the transaction is rolled back
with out freeing the mutex. A subsequent "INSERT" operation
tries to acquire the same mutex during its commit process
and the server aborts.

Fix:
===
"prepare_commit_mutex" is freed during "innobase_rollback".

storage/innobase/handler/ha_innodb.cc:
  Added code to free "prepare_commit_mutex"

The problem was that if UPDATE with subselect caused a
deadlock inside InnoDB, this deadlock was not properly
handled by the SQL layer. This meant that the SQL layer
would try to unlock the row after InnoDB had rolled
back the transaction. This caused an assertion inside
InnoDB.
  
This patch fixes the problem by checking for errors
reported by SQL_SELECT::skip_record() and not calling
unlock_row() if any errors have been reported.

This bug is similar to Bug#13586591, but for UPDATE
rather than DELETE. Similar issues in filesort/opt_range/
sql_select will be investigated and handled in the scope
of Bug#16767929

Bug #16754901 PARS_INFO_FREE NOT CALLED IN DICT_CREATE_ADD_FOREIGN_TO_DICTIONARY

Problem:

There are two situations here.  The constraint name is explicitly
given by the user and the constraint name is automatically generated
by InnoDB.  In the case of generated constraint name, it is formed by
adding table name as prefix.  The table names are stored internally in
my_charset_filename.  In the case of constraint name explicitly given
by the user, it is stored in UTF8 format itself.  So, in some
situations the constraint name is in utf8 and in some situations it is
in my_charset_filename format.  Hence this problem.

Solution:

Always store the foreign key constraint name in UTF-8 even when
automatically generated.

Bug #16754901 PARS_INFO_FREE NOT CALLED IN DICT_CREATE_ADD_FOREIGN_TO_DICTIONARY

Problem:

There was a memory leak in the function dict_create_add_foreign_to_dictionary().
The allocated pars_info_t object is not freed in the error code path.

Solution:

Allocate the pars_info_t object after the error checking.

rb#2368 in review

No commit message

eliminate a race condition over recv_sys->n_addrs which might result in a database corruption
in recovery, without reporting a recovery error.

recv_recover_page_func(): move the code segment that decrements recv_sys->n_addrs
  to the end of the function, after the call to mtr_commit()

rb://2282 approved by Inaam

GROUP BY, MYISAM 

Merge fix for Bug#16222245 from mysql-5.1 to mysql-5.5

GROUP BY, MYISAM 

Problem:-
In a query, where we are using loose index scan optimization and 
we have MIN() causes segmentation fault(where table row length 
is less then key_length).

Analysis:

While using loose index scan for MIN(), we call key_copy(), to copy 
the key data from record.
This function is using temporary record buffer to store key data 
from the record buffer.But in case where the key length is greater 
then the buffer length, this will cause a segmentation fault.


Solution:
Give a proper buffer to store a key record.


sql/opt_range.cc:
  We can't use record buffer to store key data.So, give a proper buffer to store a key record.

After a clean shutdown, InnoDB will not check the *.ibd file headers,
for maximum performance. This is unchanged before and after this
patch.

What this fix addresses is the case when crash recovery is
needed. Previously, InnoDB could load a corrupted tablespace file.

buf_page_is_corrupted(): Add the parameter check_lsn.

fil_check_first_page(): New function, to perform a consistency check
on the first page of a file. This can be overridden by setting
innodb_force_recovery.

fil_read_first_page(), fil_open_single_table_tablespace(),
fil_load_single_table_tablespace(): Invoke fil_check_first_page().

open_or_create_data_files(): Check the status of
fil_open_single_table_tablespace().

rb#2352 approved by Jimmy Yang

  
When logging to the binary log in row, updates and deletes to a BLACKHOLE
engine table are skipped.
  
It is impossible to log binary log in row format for updates and deletes to
a BLACKHOLE engine table, as no row events can be generated in these cases.
After fix, generate a warning for UPDATE/DELETE statements that modify a
BLACKHOLE table, as row events are not logged in row format.

SINGLE DATABASE; MYSQLBINLOG
      
Problem: If last subevent inside a RBR event
is skipped while replaying a binary log
using mysqlbinlog with --database=... option,
generated output is missing end marker('/*!*/;)
for that RBR event. Thence causing syntax error
while replaying the generated output.
      
Fix: Append end marker ('/*!*/;) if the last 
subevent is getting skipped.
Append end marker if the last 
subevent is getting skipped.

client/mysqlbinlog.cc:
  Append end marker if the last 
  subevent is getting skipped.

      MYSQL_READ_DEFAULT_FILE
Parsing of the plugin-dir config file option was not working due to a typo.
Fixed the typo. No test case can be added due to lack of support for 
defaults-exitra-file testing in mysql-test-run.pl.
Thanks to Sinisa for contributing the fix.

No commit message

No commit message

OPENING MISSING PARTITION

In the ha_innobase::open() call, for normal tables, there is no retry logic.
But for partitioned tables, there is a retry logic introduced as fix for:

http://bugs.mysql.com/bug.php?id=33349  
https://support.mysql.com/view.php?id=21080

The Bug#33349, does not provide sufficient information to analyze the original
problem.  The original problem reported by bug#33349 is also minor (just an
annoyance and no loss of functionality).  Most importantly, the retry logic
has been introduced without any associated test case.

So we are removing the retry logic for partitioned tables.  When the original
problem occurs, a different solution will be explored.

Problem:
In query like
select 1 from .. order by match .. against ...;
causes a debug assert failue.

Analysis:
In union type query like

(select * from order by a) order by b;
or
(select * from order by a) union (select * from order by b);

We skip resolving of order by a for 1st query and order by of a and b in 
2nd query.


This means that, in case when our order by have Item_func_match class, 
we skip resolving it.
But we maintain a ft_func_list and at the time of optimization, when we 
Perform FULLTEXT search before all regular searches on the bases of the 
list we call Item_func_match::init_search() which will cause debug assert 
as the item is not resolved.


Solution:
We will skip execution if the item is not fixed and we will not 
fix index(Item_func_match::fix_index()) for which 
Item_func_match::fix_field() is not called so that on later changes 
we can check the dependency on fix field.
bz

sql/item_func.cc:
  skiping execution, if item is not resolved.

Problem:
In query like
select 1 from .. order by match .. against ...;
causes a debug assert failue.

Analysis:
In union type query like

(select * from order by a) order by b;
or
(select * from order by a) union (select * from order by b);

We skip resolving of order by a for 1st query and order by of a and b in 
2nd query.


This means that, in case when our order by have Item_func_match class, 
we skip resolving it.
But we maintain a ft_func_list and at the time of optimization, when we 
Perform FULLTEXT search before all regular searches on the bases of the 
list we call Item_func_match::init_search() which will cause debug assert 
as the item is not resolved.


Solution:
We will skip execution if the item is not fixed and we will not 
fix index(Item_func_match::fix_index()) for which 
Item_func_match::fix_field() is not called so that on later changes 
we can check the dependency on fix field.


sql/item_func.cc:
  skiping execution, if item is not resolved.