with other alterations causes lost tables
Using RENAME clause combined with other clauses of ALTER TABLE led to
data loss (the data was there but not accessible). This could happen if the
changes do not change the table much. Adding and droppping of fields and
indices was safe. Renaming a column with MODIFY or CHANGE was unsafe operation,
if the actual column didn't change (changing from int to int, which is a noop)
Depending on the storage engine (SE) the behavior is different:
1)MyISAM/MEMORY - the ALTER TABLE statement completes
without any error but next SELECT against the new table fails.
2)InnoDB (and every other transactional table) - The ALTER TABLE statement
fails. There are the the following files in the db dir -
`new_table_name.frm` and a temporary table's frm. If the SE is file
based, then the data and index files will be present but with the old
names. What happens is that for InnoDB the table is not renamed in the
internal DDIC.
Fixed by adding additional call to mysql_rename_table() method, which should
not include FRM file rename, because it has been already done during file
names juggling.
ALTER TABLE DISABLE KEYS doesn't work when modifying the table
ENABLE|DISABLE KEYS combined with another ALTER TABLE option, different
than RENAME TO did nothing. Also, if the table had disabled keys
and was ALTER-ed then the end table was with enabled keys.
Fixed by checking whether the table had disabled keys and enabling them
in the copied table.
(this is the 5.0 patch, because 4.1 differs)
There was an improper order of doing chained operations.
To the documentor: ENABLE|DISABLE KEYS combined with RENAME TO, and no other
ALTER TABLE clause, leads to server crash independent of the presence of
indices and data in the table.
There was an improper order of doing chained operations.
To the documentor: ENABLE|DISABLE KEYS combined with RENAME TO, and no other
ALTER TABLE clause, leads to server crash independent of the presence of
indices and data in the table.
Continued implementation of WL#1324 (table name to filename encoding)
The intermediate (not temporary) files of the new table
during ALTER TABLE was visible for SHOW TABLES. These
intermediate files are copies of the original table with
the changes done by ALTER TABLE. After all the data is
copied over from the original table, these files are renamed
to the original tables file names. So they are not temporary
files. They persist after ALTER TABLE, but just with another
name.
In 5.0 the intermediate files are invisible for SHOW TABLES
because all file names beginning with "#sql" were suppressed.
This failed since 5.1.6 because even temporary table names were
converted when making file names from them. The prefix became
converted to "@0023sql". Converting the prefix during SHOW TABLES
would suppress the listing of user tables that start with "#sql".
The solution of the problem is to continue the implementation of
the table name to file name conversion feature. One requirement
is to suppress the conversion for temporary table names.
This change is straightforward for real temporary tables as there
is a function that creates temporary file names.
But the generated path names are located in TMPDIR and have no
relation to the internal table name. This cannot be used for
ALTER TABLE. Its intermediate files need to be in the same
directory as the old table files. And it is necessary to be
able to deduce the same path from the same table name repeatedly.
Consequently the intermediate table files must be handled like normal
tables. Their internal names shall start with tmp_file_prefix
(#sql) and they shall not be converted like normal table names.
I added a flags parameter to all relevant functions that are
called from ALTER TABLE. It is used to suppress the conversion
for the intermediate table files.
The outcome is that the suppression of #sql in SHOW TABLES
works again. It does not suppress user tables as these are
converted to @0023sql on file level.
This patch does also fix ALTER TABLE ... RENAME, which could not
rename a table with non-ASCII characters in its name.
It does also fix the problem that a user could create a table like
`#sql-xxxx-yyyy`, where xxxx is mysqld's pid and yyyy is the thread
ID of some other thread, which prevented this thread from running
ALTER TABLE.
Some of the above problems are mentioned in Bug 1405, which can
be closed with this patch.
This patch does also contain some minor fixes for other forgotten
conversions. Still known problems are reported as bugs 21370,
21373, and 21387.
The problem is that in a MyISAM table the following column
after a varchar field gets corrupted, if varchar field is
extended.
This should be made to work without a copy in the future, but
I'm not sure if this code is ready yet. This fix will force copy
in this case. It will not do any harm to have it here, only makes
alter table a bit slower in this case. If this should work for
MyISAM, then the bug is somewhere else in that code.
Until it works, I propose this as a temporary fix or a workaround.
Test case for the bug has been added.
- Encoding itself, implemented as a charset
"filename". Originally planned to use '.'
as an escape character, but now changed to '@'
for two reasons: "ls" does not return
file names starting with '.' considering them
as a kind of hidden files; some platforms
do not allow several dots in a file name.
- replacing many calls of my_snprintf() and
strnxmov() to the new build_table_filename().
- Adding MY_APPEND_EXT mysys flag, to append
an extention rather that replace it.
- Replacing all numeric constants in fn_format
flag arguments to their mysys definitions, e.g.
MY_UNPACK_FILENAME,
- Predictability in several function/methods:
when a table name can appear with or withot .frm
extension. Some functions/methods were changed
so accept names strictly with .frm, other - strictly
without .frm extensions. Several DBUG_ASSERTs were
added to check whether an extension is passed.
Many files:
table name to file name encoding
mysql_priv.h:
Prototypes for new table name encoding tools.
ctype-utf8.c:
Implementing "filename" charset for
table name to file name encoding.
row0mysql.c:
Fixing table name prefix.
mf_format.c:
Adding MY_APPEND_EXT processing.
Many files:
Fixing tests.
my_sys.h:
Adding new flag to append rather than replace an extension.
m_ctype.h:
Adding "filename" charset definition.
new file
mysql_fix_privilege_tables.sql, mysql_create_system_tables.sh:
Adding true BINARY/VARBINARY: fixing "password" type, not to be 0x00-padding.
Many files:
Adding true BINARY/VARBINARY: fixing tests not to output 0x00 bytes.
Adding true BINARY/VARBINARY: new pad_char structure member.
ctype-bin.c:
Adding true BINARY/VARBINARY: new pad_char structure member.
New strnxfrm, with two trailing length bytes.
field.cc:
Adding true BINARY/VARBINARY.
Ensure that ccache is also used for C programs
mysql: Ensure that 'delimiter' works the same way in batch mode as in normal mode
mysqldump: Change to use ;; (instead of //) as a stored procedure/trigger delimiter
Fixed test cases by adding missing DROP's and rename views to be of type 'v#'
Removed MY_UNIX_PATH from fn_format()
Removed current_db_used from TABLE_LIST
Removed usage of 'current_thd' in Item_splocal
Removed some compiler warnings
A bit faster longlong2str code
result set".
To enable full access to contents of I_S tables from stored functions
or statements that use them, we manipulate with thread's open tables
state and ensure that we won't cause deadlock when we open tables by
ignoring flushes and name-locks.
Building of contents of I_S.TABLES no longer requires locking of tables
since we use use handler::info() method with HA_STATUS_AUTO flag instead
of handler::update_auto_increment() for obtaining information about
auto-increment values. But this also means that handlers have to implement
support for HA_STATUS_AUTO flag (particularly InnoDB needs it).
Count null_bits separately from field offsets and adjust them in case of primary key parts.
(Previously a CREATE TABLE with a lot of null fields that was part of a primary key caused MySQL to wrongly count the number of bytes needed to store null bits)
This is a more complete bug fix for #6236
