INC_HOST_ERRORS() IS CALLED.

Description: Reverting patch 3755 for bug#11753779

Problem: Some queries with subqueries and a HAVING clause that
consists only of a column not in the select or grouping lists causes
the server to crash.

During parsing, an Item_ref is constructed for the HAVING column. The
name of the column is resolved when JOIN::prepare calls fix_fields()
on its having clause. Since the column is not mentioned in the select
or grouping lists, a ref pointer is not found and a new Item_field is
created instead. The Item_ref is replaced by the Item_field in the
tree of HAVING clauses. Since the tree consists only of this item, the
pointer that is updated is JOIN::having. However,
st_select_lex::having still points to the Item_ref as the root of the
tree of HAVING clauses.

The bug is triggered when doing filesort for create_sort_index(). When
find_all_keys() calls select->cond->walk() it eventually reaches
Item_subselect::walk() where it continues to walk the having clauses
from lex->having. This means that it finds the Item_ref instead of the
new Item_field, and Item_ref::walk() tries to dereference the ref
pointer, which is still null.

The crash is reproducible only in 5.5, but the problem lies latent in
5.1 and trunk as well.

Fix: After calling fix_fields on the having clause in JOIN::prepare(),
set select_lex::having to point to the same item as JOIN::having.

This patch also fixes a bug in 5.1 and 5.5 that is triggered if the
query is executed as a prepared statement. The Item_field is created
in the runtime arena when the query is prepared, and the pointer to
the item is saved by st_select_lex::fix_prepare_information() and
brought back as a dangling pointer when the query is executed, after
the runtime arena has been reclaimed.

Fix: Backport fix from trunk that switches to the permanent arena
before calling Item_ref::fix_fields() in JOIN::prepare().

              INC_HOST_ERRORS() IS CALLED.

Issue       : Sequence of calling inc_host_errors()
              and reset_host_errors() required some
              changes in order to maintain correct
              connection error count.

Solution    : Call to reset_host_errors() is shifted
              to a location after which no calls to
              inc_host_errors() are made.

Problem
========
            
Replication breaks in the cases if the event length exceeds 
the size of master Dump thread's max_allowed_packet.
              
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet, on addition of the  
max_event_header length exceeds the max_allowed_packet of the DUMP thread.
This causes the Dump thread to break replication and throw an error.
                      
That can happen e.g with row-based replication in Update_rows event.
            
Fix
====
          
The problem is fixed in 2 steps:

1.) The Dump thread limit to read event is increased to the upper limit
    i.e. Dump thread reads whatever gets logged in the binary log.

2.) On the slave side we increase the the max_allowed_packet for the
    slave's threads (IO/SQL) by increasing it to 1GB.

    This is done using the new server option (slave_max_allowed_packet)
    included, is used to regulate the max_allowed_packet of the  
    slave thread (IO/SQL) by the DBA, and facilitates the sending of
    large packets from the master to the slave.

    This causes the large packets to be received by the slave and apply
    it successfully.

Patch for 5.1 and 5.5: fix typo in byte comparison in rr_cmp()

WHEN KILLING

Suppose there is a query waiting for a lock.  If the user kills
this query, then "Got error -1 when reading table" error message
must not be logged in the server log file.  Since this is a user
requested interruption, no spurious error message must be logged
in the server log.  This patch will remove the error message from
the log.

approved by joh and tatjana

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Problem: mysqlbinlog exits without any error code in case of
file write error. It is because of the fact that the calls
to Log_event::print() method does not return a value and the
thus any error were being ignored.

Resolution: We resolve this problem by checking for the 
IO_CACHE::error == -1 after every call to Log_event:: print()
and terminating the further execution.

rb://1088
approved by: Marko Makela

This bug was introduced in early stages of plugin. We were not
checking for an implicit lock on sec index rec for trx_id that is
stamped on current version of the clust_index in case where the
clust_index has a previous delete marked version.

INNODB_AUTOINC_LOCK_MODE=1 AND USING TRIGGER

When an insert stmt like "insert into t values (1),(2),(3)" is
executed, the autoincrement values assigned to these three rows are
expected to be contiguous.  In the given lock mode
(innodb_autoinc_lock_mode=1), the auto inc lock will be released
before the end of the statement.  So to make the autoincrement
contiguous for a given statement, we need to reserve the auto inc
values at the beginning of the statement.  

Modified the fix based on review comment by Svoj.  

Problem
========
            
SQL statements close to the size of max_allowed_packet produce binary
log events larger than max_allowed_packet.
              
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet + max_event_header
length. Now since the event length exceeds this size master Dump
thread is unable to send the packet on to the slave.
                      
That can happen e.g with row-based replication in Update_rows event.
            
Fix
====
          
The problem was fixed by increasing the max_allowed_packet for the
slave's threads (IO/SQL) by increasing it to 1GB.
This is done using the new server option included which is used to
regulate the max_allowed_packet of the slave thread (IO/SQL).
This causes the large packets to be received by the slave and apply
it successfully.

      
Problem: After the fix for Bug#12589870, a new field that
stores the length of db name was added in the buffer that
stores the query to be executed. Unlike for the plain user
session, the replication execution did not allocate the
necessary chunk in Query-event constructor. This caused an
invalid read while accessing this field.
      
Solution: We fix this problem by allocating a necessary chunk
in the buffer created in the Query_log_event::Query_log_event()
and store the length of database name.

PROBLEM:
Threads end-up in deadlock due to locks acquired as described
below,

con1: Run Query on a table. 
  It is important that this SELECT must back-off while
  trying to open the t1 and enter into wait_for_condition().
  The SELECT then is blocked trying to lock mysys_var->mutex
  which is held by con3. The very significant fact here is
  that mysys_var->current_mutex will still point to LOCK_open,
  even if LOCK_open is no longer held by con1 at this point.

con2: Try dropping table used in con1 or query some table.
  It will hold LOCK_open and be blocked trying to lock
  kernel_mutex held by con4.

con3: Try killing the query run by con1.
  It will hold THD::LOCK_thd_data belonging to con1 while
  trying to lock mysys_var->current_mutex belonging to con1.
  But current_mutex will point to LOCK_open which is held
  by con2.

con4: Get innodb engine status
  It will hold kernel_mutex, trying to lock THD::LOCK_thd_data
  belonging to con1 which is held by con3.

So while technically only con2, con3 and con4 participate in the
deadlock, con1's mysys_var->current_mutex pointing to LOCK_open
is a vital component of the deadlock.

CYCLE = (THD::LOCK_thd_data -> LOCK_open ->
         kernel_mutex -> THD::LOCK_thd_data)

FIX:
LOCK_thd_data has responsibility of protecting,
1) thd->query, thd->query_length
2) VIO
3) thd->mysys_var (used by KILL statement and shutdown)
4) THD during thread delete.

Among above responsibilities, 1), 2)and (3,4) seems to be three
independent group of responsibility. If there is different LOCK
owning responsibility of (3,4), the above mentioned deadlock cycle
can be avoid. This fix introduces LOCK_thd_kill to handle
responsibility (3,4), which eliminates the deadlock issue.

Note: The problem is not found in 5.5. Introduction MDL subsystem 
caused metadata locking responsibility to be moved from TDC/TC to
MDL subsystem. Due to this, responsibility of LOCK_open is reduced. 
As the use of LOCK_open is removed in open_table() and 
mysql_rm_table() the above mentioned CYCLE does not form.
Revision ID for changes,
open_table() = dlenev@mysql.com-20100727133458-m3ua9oslnx8fbbvz
mysql_rm_table() = jon.hauglid@oracle.com-20101116100012-kxep9txz2fxy3nmw

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The following scenario crashes our mysql server:

1.  set global innodb_file_per_table=1;
2.  create table t1(c1 int) engine=innodb;
3.  alter table t1 discard tablespace;
4.  alter table t1 add unique index(c1);

Step 4 crashes the server.  This patch introduces a check on discarded
tablespace to avoid the crash.

rb://1041 approved by Marko Makela

               FULLTEXT INDEX AND CONCURRENT DML.

Problem Statement:
------------------
1) Create a table with FT index.
2) Enable concurrent inserts.
3) In multiple threads do below operations repeatedly
   a) truncate table
   b) insert into table ....
   c) select ... match .. against .. non-boolean/boolean mode

After some time we could observe two different assert core dumps

Analysis:
--------
1)assert core dump at key_read_cache():
Two select threads operating in-parallel on same key 
root block.
1st select thread block->status is set to BLOCK_ERROR 
because the my_pread() in read_block() is returning '0'. 
Truncate table made the index file size as 1024 and pread 
was asked to get the block of count bytes(1024 bytes) 
from offset of 1024 which it cannot read since its 
"end of file" and retuning '0' setting 
"my_errno= HA_ERR_FILE_TOO_SHORT" and the key_file_length, 
key_root[0] is same i.e. 1024. Since block status has BLOCK_ERROR 
the 1st select thread enter into the free_block() and will 
be under wait on conditional mutex by making status as 
BLOCK_REASSIGNED and goes for wait_on_readers(). Other select 
thread will also work on the same block and sees the status as 
BLOCK_ERROR and enters into free_block(), checks for BLOCK_REASSIGNED 
and asserting the server.

2)assert core dump at key_write_cache():
One select thread and One insert thread.
Select thread gets the unlocks the 'keycache->cache_lock', 
which allows other threads to continue and gets the pread() 
return value as'0'(please see the explanation above) and 
tries to get the lock on 'keycache->cache_lock' and waits 
there for the lock.
Insert thread requests for the block, block will be assigned 
from the hash list and makes the page_status as 
'PAGE_WAIT_TO_BE_READ' and goes for the read_block(), waits 
in the queue since there are some other threads performing 
reads on the same block.
Select thread which was waiting for the 'keycache->cache_lock' 
mutex in the read_block() will continue after getting the my_pread() 
value as '0' and sets the block status as BLOCK_ERROR and goes to 
the free_block() and go to the wait_for_readers().
Now the insert thread will awake and continues. and checks 
block->status as not BLOCK_READ and it asserts.  

Fix:
---
In the full text code, multiple readers of index file is not guarded. 
Hence added below below code in _ft2_search() and walk_and_match().

to lock the key_root I have used below code in _ft2_search()
 if (info->s->concurrent_insert)
    mysql_rwlock_rdlock(&share->key_root_lock[0]);

and to unlock 
 if (info->s->concurrent_insert)
   mysql_rwlock_unlock(&share->key_root_lock[0]);

INNODB_AUTOINC_LOCK_MODE=1 AND USING TRIGGER

When an insert stmt like "insert into t values (1),(2),(3)" is
executed, the autoincrement values assigned to these three rows are
expected to be contiguous.  In the given lock mode
(innodb_autoinc_lock_mode=1), the auto inc lock will be released
before the end of the statement.  So to make the autoincrement
contiguous for a given statement, we need to reserve the auto inc
values at the beginning of the statement.  

rb://1074 approved by Alexander Nozdrin

Improved random number filtering verification on
rpl_filter_tables_not_exist test.

dict_table_replace_index_in_foreign_list(): Replace the dropped index
also in the foreign key constraints of child tables that are
referencing this table.

row_ins_check_foreign_constraint(): If the underlying index is
missing, refuse the operation.

rb:1051 approved by Jimmy Yang

    
Applied the fix that updates yaSSL to 2.2.1 and fixes parsing this 
particular certificate.
Added a test case with the certificate itself.

BY A CONCURRENT TRANSACTIO

The member function QUICK_RANGE_SELECT::init_ror_merged_scan() performs
a table handler clone. Innodb does not provide a clone operation.  
The ha_innobase::clone() is not there. The handler::clone() does not 
take care of the ha_innobase->prebuilt->select_lock_type.  Because of 
this what happens is that for one index we do a locking read, and 
for the other index we were doing a non-locking (consistent) read. 
The patch introduces ha_innobase::clone() member function.  
It is implemented similar to ha_myisam::clone().  It calls the 
base class handler::clone() and then does any additional operation 
required.  I am setting the ha_innobase->prebuilt->select_lock_type 
correctly. 

rb://1060 approved by Marko

                     CAUSES RESTORE PROBLEM
Problem Statement:
------------------
mysqldump is not having the dump stmts for general_log and slow_log
tables. That is because of the fix for Bug#26121. Hence, after 
dropping the mysql database, and applying the dump by enabling the 
logging, "'general_log' table not found" errors are logged into the 
server log file.

Analysis:
---------
As part of the fix for Bug#26121, we skipped the dumping of tables 
for general_log and slow_log, because the data dump of those tables 
are taking LOCKS, which is not allowed for log tables.

Fix:
----
We came up with an approach that instead of taking both meta data 
and data dump information for those tables, take only the meta data 
dump which doesn't need LOCKS.
As part of fixing the issue we came up with below algorithm.
Design before fix:
1) mysql database is having tables like db, event,... general_log,
   ... slow_log...
2) Skip general_log and slow_log while preparing the tables list
3) Take the TL_READ lock on tables which are present in the table 
   list and do 'show create table'.
4) Release the lock.

Design with the fix:
1) mysql database is having tables like db, event,... general_log,
   ... slow_log...
2) Skip general_log and slow_log while preparing the tables list
3) Explicitly call the 'show create table' for general_log and 
   slow_log
3) Take the TL_READ lock on tables which are present in the table 
   list and do 'show create table'.
4) Release the lock.

While taking the meta data dump for general_log and slow_log the 
"CREATE TABLE" is replaced with "CREATE TABLE IF NOT EXISTS". 
This is because we skipped "DROP TABLE" for those tables, 
"DROP TABLE" fails for these tables if logging is enabled. 
Customer is applying the dump by enabling logging so, if the dump 
has "DROP TABLE" it will fail. Hence, removed the "DROP TABLE" 
stmts for those tables.
  
After the fix we could observe "Table 'mysql.general_log' 
doesn't exist" errors initially that is because in the customer 
scenario they are dropping the mysql database by enabling the 
logging, Hence, those errors are expected. Once we apply the 
dump which is taken before the "drop database mysql", the errors 
will not be there.

Fixed not to check timeout during the check table.

rpl_auto_increment_bug45679.test is refined due to not fixed in 5.1 Bug11749859-39934.

The function mysql_show_binlog_events has a local stack variable
'LOG_INFO linfo;', which is assigned to thd->current_linfo, however
this variable goes out of scope and is destroyed before clean
thd->current_linfo.

The problem is solved by moving 'LOG_INFO linfo;' to function scope.

BUG#11761686 insert_id event is not filtered.
  
Two issues are covered.
  
INSERT into autoincrement field which is not the first part in the composed primary key 
is unsafe by autoincrement logging design. The case is specific to MyISAM engine
because Innodb does not allow such table definition.
  
However no warnings and row-format logging in the MIXED mode was done, and
that is fixed.
  
Int-, Rand-, User-var log-events were not filtered along with their parent
query that made possible them to screw up execution context of the following
query.
  
Fixed with deferring their execution until the parent query.

******
Bug#11754117 

Post review fixes.

Reason:
 This is a regression happened because of changes done in code refactoring 
 in 5.1 from 5.0.

Issue: 
 While doing "Show tables" lex->verbose was being checked to avoid opening
 FRM files to get table type. In case of "Show full table", lex->verbose
 is true to indicate table type is required. In 5.0, this check was
 present which got missing in >=5.5.

Fix:
 Added the required check to avoid opening FRM files unnecessarily in case
 of "Show tables".

Stored program cache produces wrong result in same THD.