PROBLEMS

Description:- Server variable "--lower_case_tables_names"
when set to "0" on windows platform which does not support
case sensitive file operations leads to problems. A warning
message is printed in the error log while starting the
server with "--lower_case_tables_names=0". Also according to
the documentation, seting "lower_case_tables_names" to "0"
on a case-insensitive filesystem might lead to index
corruption.

Analysis:- The problem reported in the bug is:-
Creating an INNODB table 'a' and executing a query, "INSERT
INTO a SELECT a FROM A;" on a server started with
"--lower_case_tables_names=0" and running on a
case-insensitive filesystem leads innodb to flat spin.
Optimizer thinks that "a" and "A" are two different tables
as the variable "lower_case_table_names" is set to "0". As a
result, optimizer comes up with a plan which does not need a
temporary table. If the same table is used in select and
insert, a temporary table is needed. This incorrect
optimizer plan leads to infinite insertions.

Fix:- If the server is started with
"--lower_case_tables_names" set to 0 on a case-insensitive
filesystem, an error, "The server option
'lower_case_table_names'is configured to use case sensitive
table names but the data directory is on a case-insensitive
file system which is an unsupported combination. Please
consider either using a case sensitive file system for your
data directory or switching to a case-insensitive table name
mode.", is printed in the server error log and the server
exits.

Syncs "official" and our own Docker images

DESCRIPTION
===========
Inability of mysql LOAD XML command to handle empty XML
tags i.e. <row><tag/></row>. Also the behaviour is wrong
and (different than above) when there is a space in empty
tag i.e. <row><tag /></row>

ANALYSIS
========
In read_xml() the case where we encounter a close tag ('/')
we're decreasing the 'level' blindly which is wrong.
Actually when its an without-space-empty-tag (succeeding
char is '>'), we need to skip the decrement. In other words
whenever we hit a close tag ('/'), decrease the 'level'
only when (i) It's not an (without space) empty tag i.e.
<tag/> or, (ii) It is of format <row col="val" .../>

FIX
===
The switch case for '/' is modified. We've removed the
blind decrement of 'level'. We do it only when its not an
without-space-empty-tag. Also we are setting 'in_tag' to
false to let program know that we're done reading current
tag (required in the case of format <row col="val" .../>)

              VIEW


It appears that the code refactoring done as part of the
patch for the MySQL BUG#11749859 fixed this issue. This
issue is not reproducible on MySQL 5.5+ versions now.
As part of this patch, the test file "mysqldump.test" has
been updated to remove the comment which was referring to
the bug and also the line which suppresses the warning.

Analysis :
==========
During JOIN::prepare of sub-query which creates the
derived tables we call setup_procedure. Here we call
fix_fields for parameters of procedure clause. Calling
setup_procedure at this point may cause issue. If
sub-query is one of parameter being fixed it might
lead to complicated dependencies on derived tables
being prepared.

SOLUTION :
==========
In 5.6 with WL#6242, we have made procedure clause
parameters can only be NUM, so sub-queries are not
allowed as parameters. So in 5.5 we can block
sub-queries in procedure clause parameters.
This eliminates above conflicting dependencies.

PROBLEM

Whenever we insert in unique secondary index we take shared
locks on all possible duplicate record present in the table.
But while during a replace on the unique secondary index ,
we take exclusive and locks on the all duplicate record.
When the records are deleted, they are first delete marked
and later purged by the purge thread. While purging the
record we call the lock_update_delete() which in turn calls
lock_rec_inherit_to_gap() to inherit locks of the deleted
records. In repeatable read mode we inherit all the locks
from the record to the next record  but in the read commited
mode we skip inherting them as gap type locks. We make a
exception here if the lock on the records is  in shared mode
,we assume that it is set during insert for unique secondary
index and needs to be inherited to stop constraint violation.
We didnt handle the case when exclusive locks are set during
replace, we skip inheriting locks of these records and hence
causing constraint violation.

FIX

While inheriting the locks,check whether the transaction is
allowed to do TRX_DUP_REPLACE/TRX_DUP_IGNORE, if true
inherit the locks.

[ Revewied by Jimmy #rb9709]

The root cause is that x86 has a stronger memory model than the ARM
processors. And the GCC builtins didn't issue the correct fences when
setting/unsetting the lock word. In particular during the mutex release.

The solution is rewriting atomic TAS operations: replace '__sync_' by
'__atomic_' if possible.
Reviewed-by: Sunny Bains      <sunny.bains@oracle.com>
Reviewed-by: Bin Su           <bin.x.su@oracle.com>
Reviewed-by: Debarun Banerjee <debarun.banerjee@oracle.com>
Reviewed-by: Krunal Bauskar   <krunal.bauskar@oracle.com>
RB: 9782
RB: 9665
RB: 9783

send_result_set_metadata

Analysis
--------
Cursor inside trigger accessing NEW/OLD row leads server exit.

The reason for the bug was that implementation of function
create_tmp_table() was not considering Item::TRIGGER_FIELD_ITEM
as possible alternative for type of class being instantiated.
This was resulting in a mismatch between a number of columns
in result list and temp table definition. This mismatch leads
to the failure of assertion
DBUG_ASSERT(send_result_set_metadata.elements == item_list.elements)
in the method Materialized_cursor::send_result_set_metadata
in debug mode.

Fix:
---
Added code to consider Item::TRIGGER_FIELD_ITEM as valid
type while creating fields.

(cherry picked from commit 1bfe5f724bc4c24da635f632247e7d263aa53970)

Conflicts:
	mysql-test/lib/mtr_cases.pm

(cherry picked from commit 3eb933e0eb55f962404a04741767177e12a9885f)

Conflicts:
	mysql-test/mysql-test-run.pl

Issue: A select for update subquery in having clause
resulted deadlock and its transaction was rolled back
by innodb. val_XXX interfaces do not handle errors and
it do not propogate errors to its caller. sub_select
did not see this error when it called
evaluate_join_record and later made a call to innodb.
As transaction is rolled back innodb asserted.

Fix: Now evaluate_join_record checks if there is any
error reported and then return the same to its caller.

               FIND_USED_PARTITIONS | SQL/OPT_RANGE.CC:3884

Post-push fix.

               FIND_USED_PARTITIONS | SQL/OPT_RANGE.CC:3884

Issue:
-----
During partition pruning, first we identify the partition
in which row can reside and then identify the subpartition.
If we find a partition but not the subpartion then we hit
a debug assert. While finding the subpartition we check
the current thread's error status in part_val_int()
function after some operation. In this case the thread's
error status is already set to an error (multiple rows
returned) so the function returns no partition found and
results in incorrect behavior.

SOLUTION:
---------
Currently any error encountered in part_val_int is
considered a "partition not found" type error. Instead of
an assert, a check needs to be done and a valid error
returned.

			INSERT INDEX RECORD

Problem:
=======

IBUF_BITMAP_FREE bit in ibuf bitmap array is used to indicate the free
space available in leaf page. IBUF_BITMAP_FREE bit indicates free
space more than actual existing free space for the leaf page.

Solution:
=========

Ibuf_bitmap_array is not updated for the secondary index leaf page when
insert operation is done by updating a delete marked existing
record in the index.
Reviewed-by: Jimmy Yang <jimmy.yang@oracle.com>
RB: 9544

              IS REJECTED.

Analysis
========

View creation with named columns over UNION is rejected.
Consider the following view definition:

CREATE VIEW v1 (fld1, fld2) AS SELECT 1 AS a, 2 AS b
UNION ALL SELECT 1 AS a, 1 AS a;

A 'duplicate column' error was reported due to the duplicate
alias name in the secondary SELECT. The VIEW column names
are either explicitly specified or determined from the
first SELECT (which can be auto generated if not specified).
Since a duplicate column name check was performed even
for the secondary SELECTs, an error was reported.

Fix
====

Check for duplicate column names only for the named
columns if specified or only for the first SELECT.

               INCORRECT RESULTS

Issue:
-----
Updating varchar and text fields in the same update
statement can produce incorrect results. When a varchar
field is assigned to the text field and the varchar field
is then set to a different value, the text field's result
contains the varchar field's new value.

SOLUTION:
---------
Currently the blob type does not allocate space for the
string to be stored. Instead it contains a pointer to the
varchar string. So when the varchar field is changed as
part of the update statement, the value contained in the
blob also changes.

The fix would be to actually store the value by allocating
space for the blob's string. We can avoid allocating this
space when the varchar field is not being written into.

No commit message

Post-push fix: broken build on windows.
The problem is min/max macros from windows.h
which interfere with a template function callex max.

Solution: ADD_DEFINITIONS(-DNOMINMAX)

               DATABASE WHEN USING TABLE ALIASES

Issue:
-----
When using table aliases for deleting, MySQL checks
privileges against the current database and not the
privileges on the actual table or database the table
resides.


SOLUTION:
---------
While checking privileges for multi-deletes,
correspondent_table should be used since it points to the
correct table and database.

For WAIT events, fall back to other timers if CYCLE is not available.

               WARNINGS

Backporting to 5.1 and 5.5

YASSL-COMPILED SERVER/CLIENT

Description: thread_pool.thread_pool_connect hangs when the server and
client are compiled with yaSSL.

Bug-fix: Test thread_pool.thread_pool_connect was temporary disabled for
yaSSL. However, now that yaSSL is fixed it runs OK. The bug was
introduced by one of the yaSSL updates. set_current was not working for
i == 0. Now this is fixed. YASSL is updated to 2.3.7d

INITIAL STARTUP

Description: By using mysql_ssl_rsa_setup to get SSL enabled server
(after running mysqld --initialize) server don't answer properly
to "mysqladmin ping" first 30 secs after startup.

Bug-fix: YASSL validated certificate date to the minute but should have
to the second. This is why the ssl on the server side was not up right
away after new certs were created with mysql_ssl_rsa_setup. The fix for
that was submitted by Todd. YASSL was updated to 2.3.7c.

Affects at least 5.6 and 5.7. In customer case, the "client" happened to
be a replication slave, therefore his server crashed.

Bug-fix:
The bug was in yassl. Todd Ouska has provided us with the patch.

(cherry picked from commit 42ffa91aad898b02f0793b669ffd04f5c178ce39)

                MYSQLADMIN -U ROOT -P

DESCRIPTION
===========
Crash occurs when no command is given while executing
mysqladmin utility.

ANALYSIS
========
In mask_password() the final write to array 'temp_argv'
is done without checking if corresponding index 'argc'
is valid (non-negative) or not. In case its negative
(would happen when this function is called with 'argc'=0),
it may cause a SEGFAULT. Logically in such a case,
mask_password() should not have been called as it would do
no valid thing.

FIX
===
mask_password() is now called after checking 'argc'. This
function is now called only when 'argc' is positive
otherwise the process terminates

Problem :
---------
The specific issue reported in this bug is with range/list column
value that is allocated and initialized by evaluating partition
expression(item tree) during execution. After evaluation the range
list value is marked fixed [part_column_list_val]. During next
execution, we don't re-evaluate the expression and use the old value
since it is marked fixed.

Solution :
----------
One way to solve the issue is to mark all column values as not fixed
during clone so that the expression is always re-evaluated once we
attempt partition_info::fix_column_value_functions() after cloning
the part_info object during execution of DDL on partitioned table.
Reviewed-by: Jimmy Yang <Jimmy.Yang@oracle.com>
Reviewed-by: Mattias Jonsson <mattias.jonsson@oracle.com>

RB: 9424

Follow up patch to fix sys_vars.query_cache_min_res_unit_basic_32 test failure.

Valid min value for query_cache_min_res_unit is 512. But attempt
to set value greater than or equal to the ULONG_MAX(max value) is
resulting query_cache_min_res_unit value to 0. This result in
crash while searching for memory block lesser than the valid
min value to store query results.

Free memory blocks in query cache are stored in bins according
to their size. The bins are stored in size descending order.
For the memory block request the appropriate bin is searched using
binary search algorithm. The minimum free memory block request
expected is 512 bytes. And the appropriate bin is searched for block
greater than or equals to 512 bytes.

Because of the bug the query_cache_min_res_unit is set to 0. Due
to which there is a chance of request for memory blocks lesser
than the minimum size in free memory block bins. Search for bin
for this invalid input size fails and returns garbage index.
Accessing bins array element with this index is causing the issue
reported.

The valid value range for the query_cache_min_res_unit is
512 to ULONG_MAX(when value is greater than the max allowed value,
max allowed value is used i.e ULONG_MAX). While setting result unit
block size (query_cache_min_res_unit), size is memory aligned by
using a macro ALIGN_SIZE. The ALIGN_SIZE logic is as below,

  (input_size + sizeof(double) - 1) & ~(sizeof(double) - 1)

For unsigned long type variable when input_size is greater than
equal to ULONG_MAX-(sizeof(double)-1), above expression is
resulting in value 0.

Fix:
-----
Comparing value set for query_cache_min_res_unit with max
aligned value which can be stored in ulong type variable.
If it is greater then setting it to the max aligned value for
ulong type variable.

                MULTIPLE THREADS

Description:- The utility "mysqlimport" does not use
multiple threads for the execution with option
"--use-threads". "mysqlimport" while importing multiple
files and multiple tables, uses a single thread even if the
number of threads are specified with "--use-threads" option.

Analysis:- This utility uses ifdef HAVE_LIBPTHREAD to check
for libpthread library and if defined uses libpthread
library for mutlithreaing. Since HAVE_LIBPTHREAD is not
defined anywhere in the source, "--use-threads" option is
silently ignored.

Fix:- "-DTHREADS" is set to the COMPILE_FLAGS  which will
enable pthreads. HAVE_LIBPTHREAD macro is removed.

Problem :
---------
Issue-1: The root cause for the issues is that (col1 > 1) is not a
valid partition function and we should have thrown error at much early
stage [partition_info::check_partition_info]. We are not checking
sub-partition expression when partition expression is NULL.

Issue-2: Potential issue for future if any partition function needs to
change item tree during open/fix_fields. We should release changed
items, if any, before doing closefrm when we open the partitioned table
during creation in create_table_impl.

Solution :
----------
1.check_partition_info() - Check for sub-partition expression even if no
partition expression.
[partition by ... columns(...) subpartition by hash(<expr>)]

2.create_table_impl() - Assert that the change list is empty before doing
closefrm for partitioned table. Currently no supported partition function
seems to be changing item tree during open.
Reviewed-by: Mattias Jonsson <mattias.jonsson@oracle.com>

RB: 9345