for wildcard values.
The server ignored escape character before wildcards during
the calculation of priority values for sorting of a privilege
list. (Actually the server counted an escape character as an
ordinary wildcard like % or _). I.e. the table name template
with a wildcard character like 'tbl_1' had higher priority in
a privilege list than concrete table name without wildcards
like 'tbl\_1', and some privileges of 'tbl\_1' was hidden
by privileges for 'tbl_1'.
The get_sort function has been modified to ignore escaped
wildcards as usual.
type conversion.
Instead of copying of whole character string from a temporary
buffer, the server copied a short-living pointer to that string
into a long-living structure. That has been fixed.
on table creates
The problem was in incompatible syntax for key definition in CREATE
TABLE.
5.0 supports only the following syntax for key definition (see "CREATE
TABLE syntax" in the manual):
{INDEX|KEY} [index_name] [index_type] (index_col_name,...)
While 5.1 parser supports the above syntax, the "preferred" syntax was
changed to:
{INDEX|KEY} [index_name] (index_col_name,...) [index_type]
The above syntax is used in 5.1 for the SHOW CREATE TABLE output, which
led to dumps generated by 5.1 being incompatible with 5.0.
Fixed by changing the parser in 5.0 to support both 5.0 and 5.1 syntax
for key definition.
The problem occurred when one had a subquery that had an equality X=Y where
Y referred to a named select list expression from the parent select. MySQL
crashed when trying to use the X=Y equality for ref-based access.
Fixed by allowing non-Item_field items in the described case.
The ROUND(X, D) function would change the Item::decimals field during
execution to achieve the effect of a dynamic number of decimal digits.
This caused a series of bugs:
Bug #30617:Round() function not working under some circumstances in InnoDB
Bug #33402:ROUND with decimal and non-constant cannot round to 0 decimal places
Bug #30889:filesort and order by with float/numeric crashes server
Fixed by never changing the number of shown digits for DECIMAL when
used with a nonconstant number of decimal digits.
The name resolution for correlated subqueries and HAVING clauses
failed to distinguish which of two was being performed when there
was a reference to an outer aliased field.
Fixed by adding the condition that HAVING clause name resulotion
is being performed.
value when inserting into a view.
The mysql_prepare_insert function checks all fields of the target table that
directly or indirectly (through a view) are specified in the INSERT
statement to have a default value. This check can be skipped if the INSERT
statement doesn't mention any insert fields. In case of a view this allows
fields that aren't mentioned in the view to bypass the check.
Now fields of the target table are always checked to have a default value
when insert goes into a view.
When resolving references we need to take into consideration
the view "fields" and allow qualified access to them.
Fixed by extending the reference resolution to process view
fields correctly.
server crash.
The filesort implementation has an optimization for subquery execution which
consists of reusing previously allocated buffers. In particular the call to
the read_buffpek_from_file function might be skipped when a big enough buffer
for buffer descriptors (buffpeks) is already allocated. Beside allocating
memory for buffpeks this function fills allocated buffer with data read from
disk. Skipping it might led to using an arbitrary memory as fields' data and
finally to a crash.
Now the read_buffpek_from_file function is always called. It allocates
new buffer only when necessary, but always fill it with correct data.
w/ Field_date instead of Field_newdate
Field_date was still used in temp table creation.
Fixed by using Field_newdate consistently throughout the server
except when reading tables defined with older MySQL version.
No test suite is possible because both Field_date and Field_newdate
return the same values in all the metadata calls.
In a union without braces, the order by at the end is applied to the
overall union. It therefore should not interfere with the individual
select parts of the union.
Fixed by changing our parser rules appropriately.
with null values
For queries containing GROUP_CONCAT(DISTINCT fields ORDER BY fields), there
was a limitation that the DISTINCT fields had to be the same as ORDER BY
fields, owing to the fact that one single sorted tree was used for keeping
track of tuples, ordering and uniqueness. Fixed by introducing a second
structure to handle uniqueness so that the original structure has only to
order the result.
subselects into account
It is forbidden to use the SELECT INTO construction inside UNION statements
unless on the last SELECT of the union. The parser records whether it
has seen INTO or not when parsing a UNION statement. But if the INTO was
legally used in an outer query, an error is thrown if UNION is seen in a
subquery. Fixed in 5.0 by remembering the nesting level of INTO tokens and
mitigate the error unless it collides with the UNION.
There were two problems when inferring the correct field types resulting from
UNION queries.
- If the type is NULL for all corresponding fields in the UNION, the resulting
type would be NULL, while the type is BINARY(0) if there is just a single
SELECT NULL.
- If one SELECT in the UNION uses a subselect, a temporary table is created
to represent the subselect, and the result type defaults to a STRING type,
hiding the fact that the type was unknown(just a NULL value).
Fixed by remembering whenever a field was created from a NULL value and pass
type NULL to the type coercion if that is the case, and creating a string field
as result of UNION only if the type would otherwise be NULL.
