AsText() needs to know the maximum number of
characters a IEEE double precision value can
occupy to make sure there's enough buffer space.
The number was too small to hold all possible
values and this caused buffer overruns.
Fixed by correcting the calculation of the
maximum digits in a string representation of an
IEEE double precision value as printed by
String::qs_append(double).
- BUG#11986: Stored routines and triggers can fail if the code
has a non-ascii symbol
- BUG#16291: mysqldump corrupts string-constants with non-ascii-chars
- BUG#19443: INFORMATION_SCHEMA does not support charsets properly
- BUG#21249: Character set of SP-var can be ignored
- BUG#25212: Character set of string constant is ignored (stored routines)
- BUG#25221: Character set of string constant is ignored (triggers)
There were a few general problems that caused these bugs:
1. Character set information of the original (definition) query for views,
triggers, stored routines and events was lost.
2. mysqldump output query in client character set, which can be
inappropriate to encode definition-query.
3. INFORMATION_SCHEMA used strings with mixed encodings to display object
definition;
1. No query-definition-character set.
In order to compile query into execution code, some extra data (such as
environment variables or the database character set) is used. The problem
here was that this context was not preserved. So, on the next load it can
differ from the original one, thus the result will be different.
The context contains the following data:
- client character set;
- connection collation (character set and collation);
- collation of the owner database;
The fix is to store this context and use it each time we parse (compile)
and execute the object (stored routine, trigger, ...).
2. Wrong mysqldump-output.
The original query can contain several encodings (by means of character set
introducers). The problem here was that we tried to convert original query
to the mysqldump-client character set.
Moreover, we stored queries in different character sets for different
objects (views, for one, used UTF8, triggers used original character set).
The solution is
- to store definition queries in the original character set;
- to change SHOW CREATE statement to output definition query in the
binary character set (i.e. without any conversion);
- introduce SHOW CREATE TRIGGER statement;
- to dump special statements to switch the context to the original one
before dumping and restore it afterwards.
Note, in order to preserve the database collation at the creation time,
additional ALTER DATABASE might be used (to temporary switch the database
collation back to the original value). In this case, ALTER DATABASE
privilege will be required. This is a backward-incompatible change.
3. INFORMATION_SCHEMA showed non-UTF8 strings
The fix is to generate UTF8-query during the parsing, store it in the object
and show it in the INFORMATION_SCHEMA.
Basically, the idea is to create a copy of the original query convert it to
UTF8. Character set introducers are removed and all text literals are
converted to UTF8.
This UTF8 query is intended to provide user-readable output. It must not be
used to recreate the object. Specialized SHOW CREATE statements should be
used for this.
The reason for this limitation is the following: the original query can
contain symbols from several character sets (by means of character set
introducers).
Example:
- original query:
CREATE VIEW v1 AS SELECT _cp1251 'Hello' AS c1;
- UTF8 query (for INFORMATION_SCHEMA):
CREATE VIEW v1 AS SELECT 'Hello' AS c1;
This bug was introduced by the fix for the bug#27300. In this fix a section
of code was added to the Item::tmp_table_field_from_field_type method.
This section intended to create Field_geom fields for the Item_geometry_func
class and its descendants. In order to get the geometry type of the current
item it casted "this" to the Item_geometry_func* type. But the
Item::tmp_table_field_from_field_type method is also used for creation of
fields for UNION and in this case this method is called for an object of the
Item_type_holder class and the cast to the Item_geometry_func* type causes
a server crash.
Now the Item::tmp_table_field_from_field_type method correctly works when it's
called for both the Item_type_holder and the Item_geometry_func classes.
The new geometry_type variable is added to the Item_type_holder class.
The new method called get_geometry_type is added to the Item_field
and the Field classes. It returns geometry type from the field for the
Item_field and the Field_geom classes and fails an assert for other Field
descendants.
- added join cache indication in EXPLAIN (Extra column).
- prefer filesort over full scan over
index for ORDER BY (because it's faster).
- when switching from REF to RANGE because
RANGE uses longer key turn off sort on
the head table only as the resulting
RANGE access is a candidate for join cache
and we don't want to disable it by sorting
on the first table only.
Geometry fields have a result type string and a
special subclass to cater for the differences
between them and the base class (just like
DATE/TIME).
When creating temporary tables for results of
functions that return results of type GEOMETRY
we must construct fields of the derived class
instead of the base class.
Fixed by creating a GEOMETRY field (Field_geom)
instead of a generic BLOB (Field_blob) in temp
tables for the results of GIS functions that
have GEOMETRY return type (Item_geometry_func).
to 0 causes wrong (large) length to be read
from the row in _mi_calc_blob_length() when
storing NULL values in (e.g) POINT columns.
This large length is then used to allocate
a block of memory that (on some OSes) causes
trouble.
Fixed by calling the base class's
Field_blob::reset() from Field_geom::reset()
that is called when storing a NULL value into
the column.
Fix is to rewrite the MBR::overlaps() function, to compute the dimension of both
arguments, and the dimension of the intersection; test that all three dimensions are the
same (e.g., all are Polygons).
Add tests for all MBR* functions for various combinations of shapes, lines and points.
Having maybe_null flag unset for geometry/spatial functions leads to
wrong Item_func_isnull::val_int()'s results.
Fix: set maybe_null flag and add is_null() methods.
The problem is that the GEOMETRY NOT NULL can't automatically set
any value as a default one. We always tried to complete LOAD DATA
command even if there's not enough data in file. That doesn't work
for GEOMETRY NOT NULL. Now Field_*::reset() returns an error sign
and it's checked in mysql_load()
- Make the range-et-al optimizer produce E(#table records after table
condition is applied),
- Make the join optimizer use this value,
- Add "filtered" column to EXPLAIN EXTENDED to show
fraction of records left after table condition is applied
- Adjust test results, add comments
When a default of '' was specified for TEXT/BLOB columns, the specification
was silently ignored. This is presumably to be nice to applications (or
people) who generate their column definitions in a not-very-clever fashion.
For clarity, doing this now results in a warning, or an error in strict
mode.
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.
The idea is to add DEFINER-clause in CREATE PROCEDURE and CREATE FUNCTION
statements. Almost all support of definer in stored routines had been already
done before this patch.
NOTE: this patch changes behaviour of dumping stored routines in mysqldump.
Before this patch, mysqldump did not dump DEFINER-clause for stored routines
and this was documented behaviour. In order to get full information about stored
routines, one should have dumped mysql.proc table. This patch changes this
behaviour, so that DEFINER-clause is dumped.
Since DEFINER-clause is not supported in CREATE PROCEDURE | FUNCTION statements
before this patch, the clause is covered by additional version-specific comments.
