Remove some sql_print_error() calls which were triggered by user error (i.e., not server-level events at all).
Also, convert an sql_print_error -> sql_print_information for a non-error server event.
Make the encryption functions MD5(), SHA1() and ENCRYPT() return binary results.
Make MAKE_SET() and EXPORT_SET() use the correct character set for their default separator strings.
* 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 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.
The implementation of the method Item_func_reverse::val_str
for the REVERSE function modified the argument of the function.
This led to wrong results for expressions that contained
REVERSE(ref) if ref occurred somewhere else in the expressions.
Produce a warning if DATA/INDEX DIRECTORY is specified in
ALTER TABLE statement.
Ignoring of these options is documented in the symbolic links
section of the manual.
'SELECT DISTINCT a,b FROM t1' should not use temp table if there is unique
index (or primary key) on a.
There are a number of other similar cases that can be calculated without the
use of a temp table : multi-part unique indexes, primary keys or using GROUP BY
instead of DISTINCT.
When a GROUP BY/DISTINCT clause contains all key parts of a unique
index, then it is guaranteed that the fields of the clause will be
unique, therefore we can optimize away GROUP BY/DISTINCT altogether.
This optimization has two effects:
* there is no need to create a temporary table to compute the
GROUP/DISTINCT operation (or the temporary table will be smaller if only GROUP
is removed and DISTINCT stays or if DISTINCT is removed and GROUP BY stays)
* this causes the statement in effect to become updatable in Connector/Java
because the result set columns will be direct reference to the primary key of
the table (instead to the temporary table that it currently references).
Implemented a check that will optimize away GROUP BY/DISTINCT for queries like
the above.
Currently it will work only for single non-constant table in the FROM clause.
An UNIQUE KEY consisting of NOT NULL columns
was displayed as PRIMARY KEY in "DESC t1".
According to the code, that was intentional
behaviour for some reasons unknown to me.
This code was written before bitkeeper time,
so I cannot check who and why made this.
After discussing on dev-public, a decision
was made to remove this code
Server crashed in some cases when a query required a MIN/MAX
agrregation for a 'ucs2' field.
In these cases the aggregation caused calls of the function
update_tmptable_sum_func that indirectly invoked
the method Item_sum_hybrid::min_max_update_str_field()
containing a call to strip_sp for a ucs2 character set.
The latter led directly to the crash as it used my_isspace
undefined for the ucs2 character set.
Actually the call of strip_sp is not needed at all in this
situation and has been removed by the fix.
The AsBinary function returns VARCHAR data type with binary collation.
It can cause problem for clients that treat that kind of data as
different from BLOB type.
So now AsBinary returns BLOB.
This bug in Field_string::cmp resulted in a wrong comparison
with keys in partial indexes over multi-byte character fields.
Given field a is declared as a varchar(16) collate utf8_unicode_ci
INDEX(a(4)) gives us an example of such an index.
Wrong key comparisons could lead to wrong result sets if
the selected query execution plan used a range scan by
a partial index over a utf8 character field.
This also caused wrong results in many other cases.
functions in queries
Using MAX()/MIN() on table with disabled indexes (by ALTER TABLE)
results in error 124 (wrong index) from storage engine.
The problem was that optimizer use disabled index to optimize
MAX()/MIN(). Normally it must skip disabled index and perform
table scan.
This patch skips disabled indexes for min/max optimization.
Added test case for bug#18759 Incorrect string to numeric conversion.
select.test:
Added test case for bug#18759 Incorrect string to numeric conversion.
item_cmpfunc.cc:
Cleanup after fix for bug#18360 removal
there was two problems about charsets in embedded server
1. mysys/charset.c - defined there default_charset_info variable is
modified by both server and client code (particularly when
--default-charset option is handled)
In embedded server we get two codelines modifying one variable.
I created separate default_client_charset_info for client code
2. mysql->charset and mysql->options.charset initialization isn't
properly done for embedded server - necessary calls added
