The cause of im_daemon_life_cycle.imtest random failures was the following
behaviour of some implementations of LINUX threads: let's suppose that a
process has several threads (in LINUX threads, there is a separate process for
each thread). When the main process gets killed, the parent receives SIGCHLD
before all threads (child processes) die. In other words, the parent receives
SIGCHLD, when its child is not completely dead.
In terms of IM, that means that IM-angel receives SIGCHLD when IM-main is not dead
and still holds some resources. After receiving SIGCHLD, IM-angel restarts
IM-main, but IM-main failed to initialize, because previous instance (copy) of
IM-main still holds server socket (TCP-port).
Another problem here was that IM-angel restarted IM-main only if it was killed
by signal. If it exited with error, IM-angel thought it's intended / graceful
shutdown and exited itself.
So, when the second instance of IM-main failed to initialize, IM-angel thought
it's intended shutdown and quit.
The fix is
1. to change IM-angel so that it restarts IM-main if it exited with error code;
2. to change IM-main so that it returns proper exit code in case of failure.
- Starting time of a query sent by file bootstrapping wasn't initialized
and starting time defaulted to 0. This later used value by the Now-
item and is translated to 1970-01-01 11:00:00.
- marking the time with thd->set_time() before the call to
mysql_parse resolves this issue.
operations)
Before this change, the boolean predicates:
- X IS TRUE,
- X IS NOT TRUE,
- X IS FALSE,
- X IS NOT FALSE
were implemented by expanding the Item tree in the parser, by using a
construct like:
Item_func_if(Item_func_ifnull(X, <value>), <value>, <value>)
Each <value> was a constant integer, either 0 or 1.
A bug in the implementation of the function IF(a, b, c), in
Item_func_if::fix_length_and_dec(), would cause the following :
When the arguments b and c are both unsigned, the result type of the
function was signed, instead of unsigned.
When the result of the if function is signed, space for the sign could be
counted twice (in the max() expression for a signed argument, and in the
total), causing the member max_length to be too high.
An effect of this is that the final type of IF(x, int(1), int(1)) would be
int(2) instead of int(1).
With this fix, the problems found in Item_func_if::fix_length_and_dec()
have been fixed.
While it's semantically correct to represent 'X IS TRUE' with
Item_func_if(Item_func_ifnull(X, <value>), <value>, <value>),
there are however more problems with this construct.
a)
Building the parse tree involves :
- creating 5 Item instances (3 ints, 1 ifnull, 1 if),
- creating each Item calls my_pthread_getspecific_ptr() once in the operator
new(size), and a second time in the Item::Item() constructor, resulting
in a total of 10 calls to get the current thread.
Evaluating the expression involves evaluating up to 4 nodes at runtime.
This representation could be greatly simplified and improved.
b)
Transforming the parse tree internally with if(ifnull(...)) is fine as long
as this transformation is internal to the server implementation.
With views however, the result of the parse tree is later exposed by the
::print() functions, and stored as part of the view definition.
Doing this has long term consequences:
1)
The original semantic 'X IS TRUE' is lost, and replaced by the
if(ifnull(...)) expression. As a result, SHOW CREATE VIEW does not restore
the original code.
2)
Should a future version of MySQL implement the SQL BOOLEAN data type for
example, views created today using 'X IS NULL' can be exported using
mysqldump, and imported again. Such views would be converted correctly and
automatically to use a BOOLEAN column in the future version.
With 'X IS TRUE' and the current implementations, views using these
"boolean" predicates would not be converted during the export/import, and
would use integer columns instead.
The difference traces back to how SHOW CREATE VIEW preserves 'X IS NULL' but
does not preserve the 'X IS TRUE' semantic.
With this fix, internal representation of 'X IS TRUE' booleans predicates
has changed, so that:
- dedicated Item classes are created for each predicate,
- only 1 Item is created to represent 1 predicate
- my_pthread_getspecific_ptr() is invoked 1 time instead of 10
- SHOW CREATE VIEW preserves the original semantic, and prints 'X IS TRUE'.
Note that, because of the fix in Item_func_if, views created before this fix
will:
- correctly use a int(1) type instead of int(2) for boolean predicates,
- incorrectly print the if(ifnull(...), ...) expression in SHOW CREATE VIEW,
since the original semantic (X IS TRUE) has been lost.
- except for the syntax used in SHOW CREATE VIEW, these views will operate
properly, no action is needed.
Views created after this fix will operate correctly, and will preserve the
original code semantic in SHOW CREATE VIEW.
ENUMs weren't allowed to have character 0xff, a perfectly good character in some locales.
This was circumvented by mapping 0xff in ENUMs to ',', thereby prevent actual commas from
being used. Now if 0xff makes an appearance, we find a character not used in the enum and
use that as a separator. If no such character exists, we throw an error.
Any solution would have broken some sort of existing behaviour. This solution should
serve both fractions (those with 0xff and those with ',' in their enums), but
WILL REQUIRE A DUMP/RESTORE CYCLE FROM THOSE WITH 0xff IN THEIR ENUMS. :-/
That is, mysqldump with their current server, and restore when upgrading to one with
this patch.
The crash happens because second filling of the same I_S table happens in
case of subselect with order by. table->sort.io_cache previously allocated
in create_sort_index() is deleted during second filling
(function get_schema_tables_result). There are two places where
I_S table can be filled: JOIN::exec and create_sort_index().
To fix the bug we should check if the table was already filled
in one of these places and skip processing of the table in second.
The function make_unireg_sortorder ignored the fact that any
view field is represented by a 'ref' object.
This could lead to wrong results for the queries containing
both GROUP BY and ORDER BY clauses.
A wrong order of statements in QUICK_GROUP_MIN_MAX_SELECT::reset
caused a crash when a query with DISTINCT was executed by a loose scan
for an InnoDB table that had been emptied.
present.
A view created with CREATE VIEW ... ORDER BY ... cannot be resolved with
the MERGE algorithm, even when no other part of the CREATE VIEW statement
would require the view to be resolved using the TEMPTABLE algorithm.
The check for presence of the ORDER BY clause in the underlying select is
removed from the st_lex::can_be_merged() function.
The ORDER BY list of the underlying select is appended to the ORDER BY list
Objects of the class Item_equal contain an auxiliary member
eval_item of the type cmp_item that is used only for direct
evaluation of multiple equalities. Currently a multiple equality
is evaluated directly only in the cases when the equality holds
at most for one row in the result set.
The compare collation of eval_item was determined incorectly.
It could lead to returning incorrect results for some queries.
View check option clauses were ignored for updates of multi-table
views when the updates could not be performed on fly and the rows
to update had to be put into temporary tables first.
with a column of the DATETIME type could return a wrong
result set if the WHERE clause included a BETWEEN condition
on the column.
Fixed the method Item_func_between::fix_length_and_dec
where the aggregation type for BETWEEN predicates calculated
incorrectly if the first argument was a view column of the
DATETIME type.
Before this change, a local variables in stored procedures / stored functions
or triggers, when declared with a type of bit(N), would not evaluate their
value properly.
The problem was that the data was incorrectly typed as a string,
causing for example bit b'1', implemented as a byte 0x01, to be interpreted
as a string starting with the character 0x01. This later would cause
implicit conversions to integers or booleans to fail.
The root cause of this problem was an incorrect translation between field
types, like bit(N), and internal types used when representing values in Item
objects.
Also, before this change, the function HEX() would sometime print extra "0"
characters when invoked with bit(N) values.
With this fix, the type translation (sp_map_result_type, sp_map_item_type)
has been changed so that bit(N) fields are represented with integer values.
A consequence is that, for the function HEX(), when called with a stored
procedure local variable of type bit(N) as argument, HEX() is provided with an
integer instead of a string, and therefore does not print "0" padding.
A test case for Bug 12976 was present in the test suite, and has been updated.
updated.
INSERT ... ON DUPLICATE KEY UPDATE reports that a record was updated when
the duplicate key occurs even if the record wasn't actually changed
because the update values are the same as those in the record.
Now the compare_record() function is used to check whether the record was
changed and the update of a record reported only if the record differs
from the original one.
- Small difference in output from 'X509_NAME_Oneline' between OpenSSL and yaSSL. OpenSSL uses
an extension that allow's the email adress of the cert holder.
- Imported patch for yaSSL "add email to DN output"
Ignoring error codes from type conversion allows default (wrong) values to
go unnoticed in the formation of index search conditions.
Fixed by correctly checking for conversion errors.
fails
The bug was introduced with the push of the fix for bug#20953: after
the error on view creation we never reset the error state, so some
valid statements would give the same error after that.
The solution is to properly reset the error state.
This performance degradation for UPDATEs could be observed in the update
statements for which the search key cannot be converted to any valid
value of the type of the search column, like for a the condition
int_fld=99999999999999999999999999, though it can be guaranteed here
that there is no row with such a key value.
