init_read_record() - (records.cc:274)
      
Item_cond::used_tables_cache was accessed in
records.cc#init_read_record() without being initialized. It had
not been initialized because it was wrongly assumed that the
Item's variables would not be accessed, and hence
quick_fix_field() was used instead of fix_fields() to save a few
CPU cycles at creation time.

The fix is to properly initilize the Item by replacing
quick_fix_field() with fix_fields().

           deadlock was encountered

The bug is caused by an inconsistent handling of the IGNORE
clause.  A read from a const table caused a lock timeout
(ER_LOCK_TIMEOUT) in innodb.  Since the IGNORE clause was
given, the timeout was converted into a warning instead of
an error, thus not populating the diagnostics area.  When
innodb subsequently marked the transaction for rollback,
mysql asserted since the diag.area was empty.

This patch consists of only a test case, as the bug itself
was fixed by the patch for Bug #46539

       on any access

Archive engine for 5.1 (and latter) version uses a modified 
version of zlib (azlib). These two version are incompatible
so a proper upgrade is needed before tables created in 5.0 
can be used reliable.

This upgrade can be performed using repair. But due to lack 
of test its risky to allow upgrade for now. This patch addresses
only the crashing issue. Any attempt to repair will be blocked.

Eventually repair can be allowed to run through (which will also
cause an upgrade from older version to newer) but only after a 
thorough testing.

The crash occurs because SAFEMALLOC is defined for the MySQL server
but not for the Archive or Federated engines, resulting in a 
parameter mismatch between the function prototype and definition
for functions using the CALLER_INFO macro.

  memory

The server was doing a bad class typecast causing setting of 
wrong value for the maximum number of items in an internal
structure used in equality propagation.
Fixed by not doing the wrong typecast and asserting the type
of the Item where it should be done.

 values
 
 We should re-set the access method functions when changing the access
 method when switching to another index to avoid sorting.
 
 Fixed by doing a little re-engineering : encapsulating all the function
 assignment into a special function and calling it when flipping the 
 indexes.

            only const tables

The problem was caused by two shortcuts in the optimizer that
are inapplicable in the ROLLUP case.

Normally in a case when only const tables are involved in a
query, DISTINCT clause can be safely optimized away since there
may be only one row produced by the join. Similarly, we don't
need to create a temporary table to resolve DISTINCT/GROUP
BY/ORDER BY. Both of these are inapplicable when the WITH
ROLLUP modifier is present.

Fixed by disabling the said optimizations for the WITH ROLLUP
case.

Just change mysql_foo to mysql_cv_foo for one cache-id variable name.  There
was only one bad variable name, present in 5.0 and 5.1, but not in the -pe
branch.

  special chars

This script failed when the user tried passwords with multiple spaces, \, # or
' characters.  Now proper escaping and quoting is used in all contexts.

This problem occurs in the Perl version of this script, too, so fix it in both
places.

Remove a bash-ism (if ! ...).

Bug#41756 "Strange error messages about locks from InnoDB".

In JT_EQ_REF (join_read_key()) access method,
don't try to unlock rows in the handler, unless certain that
a) they were locked
b) they are not used.

Unlocking of rows is done by the logic of the nested join loop,
and is unaware of the possible caching that the access method may
have. This could lead to double unlocking, when a row
was unlocked first after reading into the cache, and then
when taken from cache, as well as to unlocking of rows which
were actually used (but taken from cache).

Delegate part of the unlocking logic to the access method,
and in JT_EQ_REF count how many times a record was actually
used in the join. Unlock it only if it's usage count is 0.

Implemented review comments.

When a sessione is closed, all temporary tables of the session are automatically 
dropped and are binlogged. But it will be binlogged with wrong database names when
the length of the temporary tables' database names are greater than the 
length of the current database name or the current database is not set.

Query_log_event's db_len is forgot to set when Query_log_event's db is set.
This patch wrote code to set db_len immediately after db has set.

Backport a ndb patch: fix bug with crash during restart, where
a mbyte incorrectly could be skipped, leading to "end of log
wo/ finding gci".

Term::ReadKey"

Add the missing module import.  Also, while here, fix a few glaring problems
with the script, and ensure that it behaves properly.  It seems this script
may have never been working correctly (e.g., reading password didn't chomp()
the result, so password was set with \n at the end; comparing the re-typed
password to original was done with inverted test).

Add END { cleanup(); } block to ensure the script removes temporary working
files.

Add SIG{INT} / SIG{QUIT} handler.

Do a bit of reorganization to make the code easier to understand.

Limit failed connection attempts to 3.

Use ./bin/mysql if it exists, and then fall back on mysql in PATH (before it
assumed 'mysql' in the path).  Print a nicer error if 'mysql' can't be called.

This has been tested on Windows (ActivePerl from cmd.exe, no cygwin needed)
and Linux.

            with temporary tables

There were two problems the test case from this bug was
triggering:

1. JOIN::rollup_init() was supposed to wrap all constant Items
into another object for queries with the WITH ROLLUP modifier
to ensure they are never considered as constants and therefore
are written into temporary tables if the optimizer chooses to
employ them for DISTINCT/GROUP BY handling.

However, JOIN::rollup_init() was called before
make_join_statistics(), so Items corresponding to fields in
const tables could not be handled as intended, which was
causing all kinds of problems later in the query execution. In
particular, create_tmp_table() assumed all constant items
except "hidden" ones to be removed earlier by remove_const()
which led to improperly initialized Field objects for the
temporary table being created. This is what was causing crashes
and valgrind errors in storage engines.

2. Even when the above problem had been fixed, the query from
the test case produced incorrect results due to some
DISTINCT/GROUP BY optimizations being performed by the
optimizer that are inapplicable in the WITH ROLLUP case.

Fixed by disabling inapplicable DISTINCT/GROUP BY optimizations
when the WITH ROLLUP modifier is present, and splitting the
const-wrapping part of JOIN::rollup_init() into a separate
method which is now invoked after make_join_statistics() when
the const tables are already known.

  subquery returning multiple rows

Error handling was missing when handling subqueires in WHERE 
and when assigning a SELECT result to a @variable.
This caused crash(es). 

Fixed by adding error handling code to both the WHERE 
condition evaluation and to assignment to an @variable.

having clause...

The fix for bug 46184 was not very complete. It was not covering
views using temporary tables and multiple tables in a FROM clause.
Fixed by reverting the fix for 46184 and making a more general
check that is checking at the right execution stage and for all
of the non-supported cases.
Now PROCEDURE ANALYZE on non-top level SELECT is also forbidden.
Updated the analyse.test and subselect.test accordingly.

Queries with nested outer joins may lead to crashes or 
bad results because an internal data structure is not handled
correctly.
The optimizer uses bitmaps of nested JOINs to determine
if certain table can be placed at a certain place in the
JOIN order.
It does maintain a bitmap describing in which JOINs 
last placed table is nested.
When it puts a table it makes sure the bit of every JOIN that
contains the table in question is set (because JOINs can be nested).
It does that by recursively setting the bit for the next enclosing
JOIN when this is the first table in the JOIN and recursively 
resetting the bit if it's the last table in the JOIN.
When it removes a table from the join order it should do the
opposite : recursively unset the bit if it's the only remaining 
table in this join and and recursively set the bit if it's removing
the last table of a JOIN.
There was an error in how the bits was set for the upper levels :
when removing a table it was setting the bit for all the enclosing 
nested JOINs even if there were more tables left in the current JOIN
(which practically means that the upper nested JOINs were not affected).
Fixed by stopping the recursion at the relevant level.

test result fix

  inside subquery

Re-setting a fulltext index was a no-operation if not all
the matches of a search were consumed by reading them.
This was preventing a joined table using a fulltext index
in a subquery that requires only 1 row of output (e.g. EXISTS) 
from working correctly because the second execution of the 
sub-query has the fulltext index cursor in a wrong state and
was not finding results.
Fixed by making the re-init code _ftb_init_index_search() 
to re-set open cursors in addition to depleted ones.

  
The prefix --skip- didn't work on 64 bit big endian machines
because of how the value pointer was casted.