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 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.
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) .
the server's binlog file, might be set to a different directory. This adds a new
"vardir" parameter, which takes the name of the directory as a value, so that the
test_bug17667() test can find the binlog.
The ALL/ANY subqueries are the subject of MIN/MAX optimization. The matter
of this optimization is to embed MIN() or MAX() function into the subquery
in order to get only one row by which we can tell whether the expression
with ALL/ANY subquery is true or false.
But when it is applied to a subquery like 'select a_constant' the reported bug
occurs. As no tables are specified in the subquery the do_select() function
isn't called for the optimized subquery and thus no values have been added
to a MIN()/MAX() function and it returns NULL instead of a_constant.
This leads to a wrong query result.
For the subquery like 'select a_constant' there is no reason to apply
MIN/MAX optimization because the subquery anyway will return at most one row.
Thus the Item_maxmin_subselect class is more appropriate for handling such
subqueries.
The Item_in_subselect::single_value_transformer() function now checks
whether tables are specified for the subquery. If no then this subselect is
handled like a UNION using an Item_maxmin_subselect object.
To make MySQL compatible with some ODBC applications, you can find
the AUTO_INCREMENT value for the last inserted row with the following query:
SELECT * FROM tbl_name WHERE auto_col IS NULL.
This is done with a special code that replaces 'auto_col IS NULL' with
'auto_col = LAST_INSERT_ID'.
However this also resets the LAST_INSERT_ID to 0 as it uses it for a flag
so as to ensure that only the first SELECT ... WHERE auto_col IS NULL
after an INSERT has this special behaviour.
In order to avoid resetting the LAST_INSERT_ID a special flag is introduced
in the THD class. This flag is used to restrict the second and subsequent
SELECTs instead of LAST_INSERT_ID.
