A string buffers which were included in the 'view' data structure
were allocated on the stack, causing an invalid pointer when used
after the function returned.
The fix: use copy of values for view->md5 & view->queries
- Make send_row_on_empty_set() return FALSE when simplify_cond() has found out
that HAVING is always FALSE
re-committing to put the fix into 5.0 and 5.1
Visual Studio 2008 Express edition does not include message compiler mc.exe
It is not possible to build MySQL server if only VC2008 Express is installed,
because we use mc.exe to generate event log messages.
This patch removes the mc.exe dependency. Generated files message.h,
message.rc and MSG00001.bin are checked into source code repository.
Instructions on how to add or change messages are added to messages.mc
The problem was that the server did not robustly handle a
unilateral roll back issued by the Resource Manager (RM)
due to a resource deadlock within the transaction branch.
By not acknowledging the roll back, the server (TM) would
eventually corrupt the XA transaction state and crash.
The solution is to mark the transaction as rollback-only
if the RM indicates that it rolled back its branch of the
transaction.
fails after the first time
Two separate problems :
1. When flattening joins the linked list used for name resolution
(next_name_resolution_table) was not updated.
Fixed by updating the pointers when extending the table list
2. The items created by expanding a * (star) as a column reference
were marked as fixed, but no cached table was assigned to them
(unlike what Item_field::fix_fields does).
Fixed by assigning a cached table (so the re-preparation is done
faster).
Note that the fix for #2 hides the fix for #1 in most cases
(except when a table reference cannot be cached).
Server crashed during a sort order optimization
of a dependent subquery:
SELECT
(SELECT t1.a FROM t1, t2
WHERE t1.a = t2.b AND t2.a = t3.c
ORDER BY t1.a)
FROM t3;
Bitmap of tables, that the reference to outer table
column uses, in addition to the regular table bit
has the OUTER_REF_TABLE_BIT bit set.
The only_eq_ref_tables function traverses this map
bit by bit simultaneously with join->map2table list.
Obviously join->map2table never contains an entry
for the OUTER_REF_TABLE_BIT pseudo-table, so the
server crashed there.
The only_eq_ref_tables function has been modified
to traverse regular table bits only like the
update_depend_map function (resetting of the
OUTER_REF_TABLE_BIT there is enough, but
resetting of the whole set of PSEUDO_TABLE_BITS
is used there for sure).
The problem is that the offset argument of the limit clause
might be truncated on a 32-bits server built without big
tables support. The truncation was happening because the
original 64-bits long argument was being cast to a 32-bits
(ha_rows) offset counter.
The solution is to check if the conversing resulted in value
truncation and if so, the offset is set to the maximum possible
value that can fit on the type.
If delayed insert fails to upgrade the lock it was not
freeing the temporary memory storage used to keep
newly constructed blob values in memory.
Fixed by iterating over the remaining rows in the delayed
insert rowset and freeing the blob storage for each row.
No test suite because it involves concurrent delayed inserts
on a table and cannot easily be made deterministic.
Added a correct valgrind suppression for Fedora 9.
The problem is that field names constructed due to wild-card
expansion done inside a stored procedure could point to freed
memory if the expansion was performed after the first call to
the stored procedure.
The problem was solved by patch for Bug#38691. The solution
was to allocate the database, table and field names in the
in the statement memory instead of table memory.
The query cache module did not check for the SQL_NO_CACHE keyword before
attempting to query the hash lookup table. This had a small performance impact.
By introducing a check on the query string before obtaining the hash mutex
we can gain some performance if the SQL_NO_CACHE directive is used often.
Select with a "NULL NOT IN" condition containing complex
subselect from the same table as in the outer select failed
with an assertion.
The failure was caused by a concatenation of circumstances:
1) an inner select was optimized by make_join_statistics to use
the QUICK_RANGE_SELECT access method (that implies an index
scan of the table);
2) a subselect was independent (constant) from the outer select;
3) a condition was pushed down into inner select.
During the evaluation of a constant IN expression an optimizer
temporary changed the access method from index scan to table
scan, but an engine handler was already initialized for index
access by make_join_statistics. That caused an assertion.
Unnecessary index initialization has been removed from
the QUICK_RANGE_SELECT::init method (QUICK_RANGE_SELECT::reset
reinvokes this initialization).
with COALESCE and JOIN
The server returned to a client the VARBINARY column type
instead of the DATE type for a result of the COALESCE,
IFNULL, IF, CASE, GREATEST or LEAST functions if that result
was filesorted in an anonymous temporary table during
the query execution.
For example:
SELECT COALESCE(t1.date1, t2.date2) AS result
FROM t1 JOIN t2 ON t1.id = t2.id ORDER BY result;
To create a column of various date/time types in a
temporary table the create_tmp_field_from_item() function
uses the Item::tmp_table_field_from_field_type() method
call. However, fields of the MYSQL_TYPE_NEWDATE type were
missed there, and the VARBINARY columns were created
by default.
Necessary condition has been added.
derived table cause crash
When a multi-UPDATE command fails to lock some table, and
subsequently succeeds, the tables need to be reopened if
they were altered. But the reopening procedure failed for
derived tables.
Extra cleanup has been added.
When running Stored Routines the Status Variable "Questions" was wrongly
incremented. According to the manual it should contain the "number of
statements that clients have sent to the server"
Introduced a new status variable 'questions' to replace the query_id
variable which currently corresponds badly with the number of statements
sent by the client.
The new behavior is ment to be backward compatible with 4.0 and at the
same time work with new features in a similar way.
This is a backport from 6.0
``FLUSH TABLES WITH READ LOCK''
Concurrent execution of 1) multitable update with a
NATURAL/USING join and 2) a such query as "FLUSH TABLES
WITH READ LOCK" or "ALTER TABLE" of updating table led
to a server crash.
The mysql_multi_update_prepare() function call is optimized
to lock updating tables only, so it postpones locking to
the last, and if locking fails, it does cleanup of modified
syntax structures and repeats a query analysis. However,
that cleanup procedure was incomplete for NATURAL/USING join
syntax data: 1) some Field_item items pointed into freed
table structures, and 2) the TABLE_LIST::join_columns fields
was not reset.
Major change:
short-living Field *Natural_join_column::table_field has
been replaced with long-living Item*.
The '@' symbol can not be used in the host name according to rfc952.
The fix:
added function check_host_name(LEX_STRING *str)
which checks that all symbols in host name string are valid and
host name length is not more than max host name length
(just moved check_string_length() function from the parser into check_host_name()).
The problem:
I_S views table does not check the presence of SHOW_VIEW_ACL|SELECT_ACL
privileges for a view. It leads to discrepancy between SHOW CREATE VIEW
and I_S.VIEWS.
The fix:
added appropriate check.
When analyzing the possible index use cases the server was re-using an internal structure.
This is wrong, as this internal structure gets updated during the analysis.
Fixed by making a copy of the internal structure for every place it needs to be used.
Also stopped the generation of empty SEL_TREE structures that unnecessary
complicate the analysis.
from stored procedure.
Problem: we replace all references to local variables in stored procedures
with NAME_CONST(name, value) logging to the binary log. However, if the
value's collation differs we might get an 'illegal mix of collation'
error as we don't pass the collation to the function.
Fix: pass the value's collation to NAME_CONST().
Note: actually we should pass to NAME_CONST() the value's derivation as well.
It's impossible without the parser modifying. Now we always set the
derivation to DERIVATION_IMPLICIT, the same as local variables have.
Server created "arc" directories inside database directories and
maintained there useless copies of .frm files.
Creation and renaming procedures of those copies as well as
creation of "arc" directories has been discontinued.
Removal procedure has been kept untouched to be able to
cleanup existent database directories by the DROP DATABASE
query. Also view renaming procedure has been updated to remove
these directories.
JOIN for the subselect wasn't cleaned if we came upon an error
during sub_select() execution. That leads to the assertion failure
in close_thread_tables()
part of the 6.0 code backported
per-file comments:
mysql-test/r/sp-error.result
Bug#37949 Crash if argument to SP is a subquery that returns more than one row
test result
mysql-test/t/sp-error.test
Bug#37949 Crash if argument to SP is a subquery that returns more than one row
test case
sql/sp_head.cc
Bug#37949 Crash if argument to SP is a subquery that returns more than one row
lex->unit.cleanup() call added if not substatement
A stored procedure involving substrings could crash the server on certain
platforms because of invalid memory reads.
During storing the new blob-field value, the cached value's address range
overlapped that of the new field value. This caused problems when the
cached value storage was reallocated to provide access for a new
characater set representation. The patch checks the address ranges, and if
they overlap, the new field value is copied to a new storage before it is
converted to the new character set.
The fix for bug 31887 was incomplete : it assumes that all the
field types returned by the IS_NUM macro are descendants of
Item_num and tries to zero-fill the values before doing constant
substitution with such fields when they are compared to constant string
values.
The only exception to this is Field_timestamp : it's in the IS_NUM
macro, but is not a descendant of Field_num.
Fixed by excluding timestamp fields (Field_timestamp) when zero-filling
when converting the constant to compare with to a string.
Note that this will not exclude the timestamp columns from const
propagation.
The problem here is that symbols can not be loaded, because symbol
path is not set and default path does not include the directory
where PDB is located.
The problem is _not_ reproducible on the same machine where
mysqld.exe is built - if PDB is not found in the symbol path,
dbghelp would fallback to fully qualified PDB path as given in the
executable header and on the build host this will succeed.
The solution is to calculate symbol path and pass it to SymInitialize()
call.
in open_table()
Problem: repeating "CREATE... ( AUTOINCREMENT) ... SELECT" may lead to
an assertion failure.
Fix: reset table->auto_increment_field_not_null after each record
writing.
INSERT .. SELECT .. ON DUPLICATE KEY UPDATE col=DEFAULT
In order to get correct values from update fields that
belongs to the SELECT part in the INSERT .. SELECT .. ON
DUPLICATE KEY UPDATE statement, the server adds referenced
fields to the select list. Part of the code that does this
transformation is shared between implementations of
the DEFAULT(col) function and the DEFAULT keyword (in
the col=DEFAULT expression), and an implementation of
the DEFAULT keyword is incomplete.
returns unexpected result
If:
1. a table has a not nullable BIT column c1 with a length
shorter than 8 bits and some additional not nullable
columns c2 etc, and
2. the WHERE clause is like: (c1 = constant) AND c2 ...,
the SELECT query returns unexpected result set.
The server stores BIT columns in a tricky way to save disk
space: if column's bit length is not divisible by 8, the
server places reminder bits among the null bits at the start
of a record. The rest bytes are stored in the record itself,
and Field::ptr points to these rest bytes.
However if a bit length of the whole column is less than 8,
there are no remaining bytes, and there is nothing to store in
the record at its regular place. In this case Field::ptr points
to bytes actually occupied by the next column in a record.
If both columns (BIT and the next column) are NOT NULL,
the Field::eq function incorrectly deduces that this is the
same column, so query transformation/equal item elimination
code (see build_equal_items_for_cond) may mix these columns
and damage conditions containing references to them.
used causes server crash.
When the loose index scan access method is used values of aggregated functions
are precomputed by it. Aggregation of such functions shouldn't be performed
in this case and functions should be treated as normal ones.
The create_tmp_table function wasn't taking this into account and this led to
a crash if a query has MIN/MAX aggregate functions and employs temporary table
and loose index scan.
Now the JOIN::exec and the create_tmp_table functions treat MIN/MAX aggregate
functions as normal ones when the loose index scan is used.
