Analysis: There were two problems. (1) if partition table was
created using lower_case_tables = 1 on windows we did find the
correct table but we did not set share->ib_table correctly.
(2) we did open table on dictionary but did not increase
mysql_open_tables.
Fix: In xtradb allow access to tables with incorrect
lower case names (warning is printed to error log). If
table is opened increase mysql_open_tables count to avoid
crash on flush tables.
Item_func_coalesce::fix_length_and_dec() calls
Item_func::count_string_result_length()) which called agg_arg_charsets()
with wrong flags, so the collation derivation of the COALESCE result was
not properly set to DERIVATION_COERCIBLE. It erroneously stayed
DERIVATION_NUMERIC. So GREATEST() misinterpreted the argument as
a number rather that a string and did not calculate its own length properly.
mysqldump --routine fails to dump databases containing backslash ("\")
character. This happened because escaped database name was being used as an
identifier while changing current database. Such identifers are not supposed
to be escaped, they must be properly quoted instead.
Analysis: debug only assertion I_S function (IS is XtraDB feature) is calling
buf_block_get_frame on any page it reads, which debug-asserts that the page is
buffer-fixed, which is not the case in I_S query.
Fixed by holding the buffer page mutex while the fields are read directly.
make it possible to change feedback plugin wait intervals
* only in debug builds
* and force the feedback report to be ignored
update the test to use this feature
MDEV-8938 Server Crash on Update with joins
Make unique table check after setup_fields of update because unique table can materialize table and we do not need field resolving after materialization.
When CHANGE MASTER was executed as a PS, its attributes were wrongly
getting reset toward the end of PREPARE. As a result, the subsequent
executions had no effect. Fixed by making sure that the CHANGE MASTER
attributes are preserved during the lifetime of the PS.
Problem was in rewriting left expression which had 2 references on it. Solved with making subselect reference main.
Item_in_optimized can have not Item_in_subselect reference in left part so type casting with no check is dangerous.
Item::cols() should be checked after Item::fix_fields().
The test restarts the server and expects that the feedback plugin
will send a report on shutdown, and will write about it in the error
log. But the server is only given 10 sec to shut down properly,
which is not always enough.
Added a parameter to restart_mysqld.inc, and set it to a bigger
value in feedback_plugin_send
The culprit is the feedback_plugin_load test, which is run both separately
and from inside feedback_plugin_send.test. The test queries I_S.FEEDBACK,
and every time it does, 'FEEDBACK used' value is increased.
Fixed by checking that the value is increased instead of recording the actual
value in the result file.
The real problem is that when innodb.xa_recovery test intentionally
crashes the server, system tables can be opened and marked as crashed,
and the next test in line gets blamed for the error which appears
in the error log.
Fixed by flushing the tables before crashing the server
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.
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
