The bug caused a crash of the server if a subquery with
ORDER BY DESC used the range access method.
The bug happened because the method QUICK_SELECT_DESC::reset
was not reworked after MRR interface had been introduced.
The bug was due to a loss happened during a refactoring made
on May 30 2005 that modified the function JOIN::reinit.
As a result of it for any subquery the value of offset_limit_cnt
was not restored for the following executions. Yet the first
execution of the subquery made it equal to 0.
The fix restores this value in the function JOIN::reinit.
mysqldump did not select the correct database before trying to dump
views from it. this resulted in an empty result set, which in turn
startled mysql-dump into a core-dump. this only happened for views,
not for tables, and was only visible with multiple databases that
weren't by sheer luck in the order mysqldump required, anyway. this
fixes by selecting the correct database before dumping views; it also
catches the empty set-condition if it should occur for other reasons.
DESCRIBE returned the type BIGINT for a column of a view if the column
was specified by an expression over values of the type INT.
E.g. for the view defined as follows:
CREATE VIEW v1 SELECT COALESCE(f1,f2) FROM t1
DESCRIBE returned type BIGINT for the only column of the view if f1,f2 are
columns of the INT type.
At the same time DESCRIBE returned type INT for the only column of the table
defined by the statement:
CREATE TABLE t2 SELECT COALESCE(f1,f2) FROM t1.
This inconsistency was removed by the patch.
Now the code chooses between INT/BIGINT depending on the
precision of the aggregated column type.
Thus both DESCRIBE commands above returns type INT for v1 and t2.
mysqldump did not select the correct database before trying to dump
views from it. this resulted in an empty result set, which in turn
startled mysql-dump into a core-dump. this only happened for views,
not for tables, and was only visible with multiple databases that
weren't by sheer luck in the order mysqldump required, anyway. this
fixes by selecting the correct database before dumping views; it also
catches the empty set-condition if it should occur for other reasons.
do not look for client-specific commands while inside a multi-line comment.
we will allow multi-comments pretty much anywhere within SQL-statements,
but client-specific commands (help, use, print, ...) must be the first token
in the input.
The Federated storage engine used Field methods that had arbitrary limits on
the amount of data they could process, which caused problems with data
over that limit (4K). By removing those Field methods and just using
features of the String class, we can avoid this problem.
The bug is thqt we use some nonstandard assembly codes in our strings
source, and some assemblers don't know what to do with them: Specifically,
Sun's Solaris assembler and Apple's Darwin assembler balk at them.
This patch, rather than trying to test for properties of the assembler,
which Autoconf doesn't have any decent facilites for, instead tries to
compile the code in question and disables assembly if it fails.
There's still the problem of unportable assembly, but I'll leave that
to someone who feels like rewriting and debugging it.
* don't use join cache when the incoming data set is already ordered
for ORDER BY
This choice must be made because join cache will effectively
reverse the join order and the results will be sorted by the index
of the table that uses join cache.
Changed the error reporting (and a crash) when inserting data into a
MERGE table that has no underlying tables or no INSERT_METHOD specified
by reporting that it is read-only.
may return a wrong result.
An Item_sum_hybrid object has the was_values flag which indicates whether any
values were added to the sum function. By default it is set to true and reset
to false on any no_rows_in_result() call. This method is called only in
return_zero_rows() function. An ALL/ANY subquery can be optimized by MIN/MAX
optimization. The was_values flag is used to indicate whether the subquery
has returned at least one row. This bug occurs because return_zero_rows() is
called only when we know that the select will return zero rows before
starting any scans but often such information is not known.
In the reported case the return_zero_rows() function is not called and
the was_values flag is not reset to false and yet the subquery return no rows
Item_func_not_all and Item_func_nop_all functions return a wrong
comparison result.
The end_send_group() function now calls no_rows_in_result() for each item
in the fields_list if there is no rows were found for the (sub)query.
The problem is that the author used the wrong function to send a warning to the
user about truncation of data. push_warning() takes a constant string and
push_warning_printf() takes a format and variable arguments to fill it.
Since the string we were complaining about contains percent characters, the
printf() code interprets the "%Y" et c. that the user sends. That's wrong, and
often causes a crash, especially if the date mentions seconds, "%s".
A alternate fix would be to use push_warning_printf(..., "%s", warn_buff) .
