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 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) .
dropping/creating tables".
The bug could lead to a crash when multi-delete statements were
prepared and used with temporary tables.
The bug was caused by lack of clean-up of multi-delete tables before
re-execution of a prepared statement. In a statement like
DELETE t1 FROM t1, t2 WHERE ... the first table list (t1) is
moved to lex->auxilliary_table_list and excluded from lex->query_tables
or select_lex->tables. Thus it was unaccessible to reinit_stmt_before_use
and not cleaned up before re-execution of a prepared statement.
"temporary table with data directory option fails"
myisam should not use user-specified table name when creating
temporary tables and use generated connection specific real name.
Test included.
CHECK TABLE could complain about a fully intact spatial index.
A wrong comparison operator was used for table checking.
The result was that it checked for non-matching spatial keys.
This succeeded if at least two different keys were present,
but failed if only the matching key was present.
I fixed the key comparison.
'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
This was another manifestation of the problems fixed in the
patch for bug 16674.
Wrong calculation of length of the search prefix in the pattern
string led here to a wrong result set for a query in 4.1.
The bug could be demonstrated for any multi-byte character set.
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.
The length of the prefix of the pattern string in the LIKE predicate that
determined the index range to be scanned was calculated incorrectly for
multi-byte character sets.
As a result of this in 4. 1 the the scanned range was wider then necessary
if the prefix contained not only one-byte characters.
In 5.0 additionally it caused missing some rows from the result set.
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
tables
Currently in INSERT ... SELECT ... LIMIT ... the compiler uses a
temporary table to store the results of SELECT ... LIMIT .. and then
uses that table as a source for INSERT. The problem is that in some cases
it actually skips the LIMIT clause in doing that and materializes the
whole SELECT result set regardless of the LIMIT.
This fix is limiting the process of filling up the temp table with only
that much rows that will be actually used by propagating the LIMIT value.
