LOSS
ANALYSIS:
=========
When converting from a BLOB/TEXT type to a smaller
BLOB/TEXT type, no warning/error is reported to the user
informing about the truncation/data loss.
FIX:
====
We are now reporting a warning in non-strict mode and an
appropriate error in strict mode.
backport ce6c0e584e
MDEV-8960: Can't refer the same column twice in one ALTER TABLE
Problem was that if column was created in alter table when
it was refered again it was not tried to find from list
of current columns.
mysql_prepare_alter_table:
There is two cases
(1) If alter table adds a new column and then later alter
changes the field definition, there was no check from
list of new columns, instead an incorrect error was given.
(2) If alter table adds a new column and then later alter
changes the default, there was no check from list of
new columns, instead an incorrect error was given.
FILE
PROBLEM
In 5.5 when doing doing a rename of a column ,we ignore the case between
old and new column names while comparing them,so if the change is just
the case then we don't even mark the field FIELD_IS_RENAMED ,we just update
the frm file ,but don't recreate the table as is the norm when alter is
used.This leads to inconsistency in the innodb data dictionary which causes
index creation to fail.
FIX
According to the documentation any innodb column rename should trigger
rebuild of the table. Therefore for innodb tables we will do a strcmp()
between the column names and if there is case change in column name
we will trigger a rebuild.
TABLES IN INCORRECT ENGINE
PROBLEM:
CREATE/ALTER TABLE currently can move system tables like
mysql.db, user, host etc, to engines other than MyISAM. This is not
completely supported as of now, by mysqld. When some of system tables
like plugin, servers, event, func, *_priv, time_zone* are moved
to innodb, mysqld restart crashes. Currently system tables
can be moved to BLACKHOLE also!!!.
ANALYSIS:
The problem is that there is no check before creating or moving
a system table to some particular engine.
System tables are suppose to be residing in MyISAM. We can think
of restricting system tables to exist only in MyISAM. But, there could
be future needs of these system tables to be part of other engines
by design. For eg, NDB cluster expects some tables to be on innodb
or ndb engine. This calls for a solution, by which system
tables can be supported by any desired engine, with minimal effort.
FIX:
The solution provides a handlerton interface using which,
mysqld server can query particular storage engine handlerton for
system tables that it supports. This way each storage engine
layer can define their own system database and system tables.
The check_engine() function uses the new handlerton function
ha_check_if_supported_system_table() to check if db.tablename
provided in the DDL is supported by the SE.
Note: This fix has modified a test in help.test, which was moving
mysql.help_* to innodb. The primary intention of the test was not
to move them between engines.
TABLES IN INCORRECT ENGINE
PROBLEM:
CREATE/ALTER TABLE currently can move system tables like
mysql.db, user, host etc, to engines other than MyISAM. This is not
completely supported as of now, by mysqld. When some of system tables
like plugin, servers, event, func, *_priv, time_zone* are moved
to innodb, mysqld restart crashes. Currently system tables
can be moved to BLACKHOLE also!!!.
ANALYSIS:
The problem is that there is no check before creating or moving
a system table to some particular engine.
System tables are suppose to be residing in MyISAM. We can think
of restricting system tables to exist only in MyISAM. But, there could
be future needs of these system tables to be part of other engines
by design. For eg, NDB cluster expects some tables to be on innodb
or ndb engine. This calls for a solution, by which system
tables can be supported by any desired engine, with minimal effort.
FIX:
The solution provides a handlerton interface using which,
mysqld server can query particular storage engine handlerton for
system tables that it supports. This way each storage engine
layer can define their own system database and system tables.
The check_engine() function uses the new handlerton function
ha_check_if_supported_system_table() to check if db.tablename
provided in the DDL is supported by the SE.
Note: This fix has modified a test in help.test, which was moving
mysql.help_* to innodb. The primary intention of the test was not
to move them between engines.
TO POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
ALTER TABLE MODIFY/CHANGE ... FIRST did nothing except renaming
columns if new version of the table had exactly the same
structure as the old one (i.e. as result of such statement, names
of columns changed their order as specified but data in columns
didn't). The same thing happened for ALTER TABLE DROP COLUMN/ADD
COLUMN statements which were supposed to produce new version of
table with exactly the same structure as the old version of table.
I.e. in the latter case the result was the same as if old column
was renamed instead of being dropped and new column with default
as value being created.
Both these problems were caused by the fact that ALTER TABLE
implementation incorrectly interpreted both these situations as
simple renaming of columns and assumed that in-place ALTER TABLE
algorithm could have been used for them.
This patch fixes this problem by ensuring that in cases when some
column is moved to the first position or some column is dropped
the default ALTER TABLE algorithm involving table copying is
always used. This is achieved by detecting such situations in
mysql_prepare_alter_table() and setting Alter_info::change_level
to ALTER_TABLE_DATA_CHANGED for them.
mysql-test/r/alter_table.result:
Added test for bug #12652385 - "61493: REORDERING COLUMNS TO
POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
mysql-test/t/alter_table.test:
Added test for bug #12652385 - "61493: REORDERING COLUMNS TO
POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
sql/sql_table.cc:
Changed mysql_prepare_alter_table() to detect situations in
which we some column moved to the first position or some column
is dropped and ensure that such ALTER TABLE statements won't
be carried out using in-place algorithm. The latter could have
happened before this patch if new version of table had the same
structure as the old one (except the column names).
TO POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
ALTER TABLE MODIFY/CHANGE ... FIRST did nothing except renaming
columns if new version of the table had exactly the same
structure as the old one (i.e. as result of such statement, names
of columns changed their order as specified but data in columns
didn't). The same thing happened for ALTER TABLE DROP COLUMN/ADD
COLUMN statements which were supposed to produce new version of
table with exactly the same structure as the old version of table.
I.e. in the latter case the result was the same as if old column
was renamed instead of being dropped and new column with default
as value being created.
Both these problems were caused by the fact that ALTER TABLE
implementation incorrectly interpreted both these situations as
simple renaming of columns and assumed that in-place ALTER TABLE
algorithm could have been used for them.
This patch fixes this problem by ensuring that in cases when some
column is moved to the first position or some column is dropped
the default ALTER TABLE algorithm involving table copying is
always used. This is achieved by detecting such situations in
mysql_prepare_alter_table() and setting Alter_info::change_level
to ALTER_TABLE_DATA_CHANGED for them.
CLAUSE FAILS OR ABORTS SERVER".
Attempt to re-execute prepared ALTER TABLE statement which
involves .FRM-only changes and also have RENAME clause led
to unwarranted 'Table doesn't exist' error in production
builds and assertion failure for debug builds.
This problem stemmed from the fact that for such ALTER TABLE
mysql_alter_table() code changed table list element for table
to be altered when it tried to re-open table under new name.
Since this change was not reverted back before next
re-execution, it made this statement re-execution unsafe.
This fix addresses this problem by avoiding changing table list
element from the main table list in such a situation. Instead
temporary TABLE_LIST object is used.
mysql-test/r/alter_table.result:
Added test case for bug#11938039 "RE-EXECUTION OF FRM-ONLY
ALTER TABLE WITH RENAME CLAUSE FAILS OR ABORTS SERVER".
mysql-test/t/alter_table.test:
Added test case for bug#11938039 "RE-EXECUTION OF FRM-ONLY
ALTER TABLE WITH RENAME CLAUSE FAILS OR ABORTS SERVER".
sql/sql_table.cc:
Changed mysql_alter_table() not to modify table list element
for the table being altered while re-opening table after
.FRM-only changes. Doing this made .FRM-only ALTER TABLE
which also had RENAME clause unsafe for re-execution.
CLAUSE FAILS OR ABORTS SERVER".
Attempt to re-execute prepared ALTER TABLE statement which
involves .FRM-only changes and also have RENAME clause led
to unwarranted 'Table doesn't exist' error in production
builds and assertion failure for debug builds.
This problem stemmed from the fact that for such ALTER TABLE
mysql_alter_table() code changed table list element for table
to be altered when it tried to re-open table under new name.
Since this change was not reverted back before next
re-execution, it made this statement re-execution unsafe.
This fix addresses this problem by avoiding changing table list
element from the main table list in such a situation. Instead
temporary TABLE_LIST object is used.
The problem was that doing ALTER TABLE on a table which had a key
on a TEXT/BLOB column with a prefix longer than the maximum number
of characteres in this column (as per the character set), by mistake,
caused an error (Error 1170 - ER_BLOB_KEY_WITHOUT_LENGTH).
This bug not repeatable in 5.5.
This patch adds a regression test to alter_table.test and
contains no code changes.
The problem was that doing ALTER TABLE on a table which had a key
on a TEXT/BLOB column with a prefix longer than the maximum number
of characteres in this column (as per the character set), by mistake,
caused an error (Error 1170 - ER_BLOB_KEY_WITHOUT_LENGTH).
This bug not repeatable in 5.5.
This patch adds a regression test to alter_table.test and
contains no code changes.
table copy".
This patch only adds test case as the bug itself was addressed
by Ramil's fix for bug 50946 "fast index creation still seems
to copy the table".
table copy".
This patch only adds test case as the bug itself was addressed
by Ramil's fix for bug 50946 "fast index creation still seems
to copy the table".
corruption and crash results
An index creation statement where the index key
is larger/wider than the column it references
should throw an error.
A statement like:
CREATE TABLE t1 (a CHAR(1), PRIMARY KEY (A(255)))
did not error, but a segmentation fault followed when
an insertion was attempted on the table
The partial key validiation clause has been
restructured to (hopefully) better document which
uses of partial keys are valid.
corruption and crash results
An index creation statement where the index key
is larger/wider than the column it references
should throw an error.
A statement like:
CREATE TABLE t1 (a CHAR(1), PRIMARY KEY (A(255)))
did not error, but a segmentation fault followed when
an insertion was attempted on the table
The partial key validiation clause has been
restructured to (hopefully) better document which
uses of partial keys are valid.
freezes (win) the server
The check for equality was assuming the field object is always
created. If it's not it was de-referencing a NULL pointer.
Fixed to use the data in the create object instead.
freezes (win) the server
The check for equality was assuming the field object is always
created. If it's not it was de-referencing a NULL pointer.
Fixed to use the data in the create object instead.
- Moved some code from innodb_plugin to xtradb, to ensure that all tests runs
- Did changes in pbxt and maria storage engines becasue of changes in thd->query
- Reverted wrong code in sql_table.cc for how ROW_FORMAT is used.
This is a re-commit of Monty's merge to eliminate an extra commit from
MySQL-5.1.42 that was accidentally included in the merge.
This is a merge of the MySQL 5.1.41 clone-off (clone-5.1.41-build). In
case there are any extra changes done before final MySQL 5.1.41
release, these will need to be merged later before MariaDB 5.1.41
release.
An ALTER TABLE statement which added a column and added
a non-partial index on it failed with:
"ERROR 1089 (HY000): Incorrect sub part key; the used
key part isn't a string, the used length is longer than
the key part, or the storage engine doesn't support unique
sub keys"
In a check introduced to fix an earlier bug (no. 26794),
to allow for indices on spatial type columns, the
test expression was flawed (a logical OR was used instead
of a logical AND), which led to this regression.
The code in question does a sanity check on the key, and
the flawed code mistakenly classified any index created
in the way specified above as a partial index. Since
many data types does not allow partial indices, the
statement would fail.
An ALTER TABLE statement which added a column and added
a non-partial index on it failed with:
"ERROR 1089 (HY000): Incorrect sub part key; the used
key part isn't a string, the used length is longer than
the key part, or the storage engine doesn't support unique
sub keys"
In a check introduced to fix an earlier bug (no. 26794),
to allow for indices on spatial type columns, the
test expression was flawed (a logical OR was used instead
of a logical AND), which led to this regression.
The code in question does a sanity check on the key, and
the flawed code mistakenly classified any index created
in the way specified above as a partial index. Since
many data types does not allow partial indices, the
statement would fail.
We set up DATE and TIMESTAMP differently in field-creation than we
did in field-MD creation (for CREATE). Admirably, ALTER TABLE
detected this and didn't damage any data, but it did initiate a
full copy/conversion, which we don't really need to do.
Now we describe Field and Create_field the same for those types.
As a result, ALTER TABLE that only changes meta-data (like a
field's name) no longer forces a data-copy when there needn't
be one.
mysql-test/r/alter_table.result:
0 rows should be affected when a meta-data change is enough ALTER TABLE.
mysql-test/t/alter_table.test:
add test-case: show that we don't do a full data-copy on ALTER TABLE
when we don't need to.
sql/field.cc:
Remove Field_str::compare_str_field_flags() (now in Field/Create_field as
field_flags_are_binary().
Correct some field-lengths!
sql/field.h:
Clean-up: use defined constants rather than numeric literals for certain
field-lengths.
Add enquiry-functions binaryp() to classes Field and Create_field.
This replaces field.cc's Field_str::compare_str_field_flags().
We set up DATE and TIMESTAMP differently in field-creation than we
did in field-MD creation (for CREATE). Admirably, ALTER TABLE
detected this and didn't damage any data, but it did initiate a
full copy/conversion, which we don't really need to do.
Now we describe Field and Create_field the same for those types.
As a result, ALTER TABLE that only changes meta-data (like a
field's name) no longer forces a data-copy when there needn't
be one.
The problem was that appending values to the end of an existing
ENUM or SET column was being treated as table data modification,
preventing a immediately (fast) table alteration that occurs when
only table metadata is being modified.
The cause was twofold: adding a enumeration or set members to the
end of the list of valid member values was not being considered
a "compatible" table alteration, and for SET columns, the check
was being done upon the max display length and not the underlying
(pack) length of the field.
The solution is to augment the function that checks wether two ENUM
or SET fields are compatible -- by comparing the pack lengths and
performing a limited comparison of the member values.
mysql-test/r/alter_table.result:
Add test case result for Bug#45567
mysql-test/t/alter_table.test:
Add test case for Bug#45567
sql/field.cc:
Check whether two fields can be considered 'equal' for table
alteration purposes. Fields are equal if they retain the same
pack length and if new members are added to the end of the list.
sql/field.h:
Add comment and remove method.
The problem was that appending values to the end of an existing
ENUM or SET column was being treated as table data modification,
preventing a immediately (fast) table alteration that occurs when
only table metadata is being modified.
The cause was twofold: adding a enumeration or set members to the
end of the list of valid member values was not being considered
a "compatible" table alteration, and for SET columns, the check
was being done upon the max display length and not the underlying
(pack) length of the field.
The solution is to augment the function that checks wether two ENUM
or SET fields are compatible -- by comparing the pack lengths and
performing a limited comparison of the member values.
Author: Stewart Smith
mysql-test/r/alter_table.result:
Testing of ALTER TABLE .. DROP DEFAULT
mysql-test/r/limit.result:
Testing of LIMIT ... OFFSET
mysql-test/t/alter_table.test:
Testing of ALTER TABLE .. DROP DEFAULT
mysql-test/t/limit.test:
Testing of LIMIT ... OFFSET
added ability for TINY[MEDIUM] text fields
to be converted to greater subtype during
alter if necessary(altered charset)
mysql-test/r/alter_table.result:
test result
mysql-test/t/alter_table.test:
test case
sql/sql_table.cc:
added ability for TINY[MEDIUM] text fields
to be converted to greater subtype during
alter if necessary(altered charset)
