Due to an internal change in the server code in between 5.1 and 5.5
(wl#2649) the hash function used in KEY partitioning changed
for numeric and date/time columns (from binary hash calculation
to character based hash calculation).
Also enum/set changed from latin1 ci based hash calculation to
binary hash between 5.1 and 5.5. (bug#11759782).
These changes makes KEY [sub]partitioned tables on any of
the affected column types incompatible with 5.5 and above,
since the calculation of partition id differs.
Also since InnoDB asserts that a deleted row was previously
read (positioned), the server asserts on delete of a row that
is in the wrong partition.
The solution for this situation is:
1) The partitioning engine will check that delete/update will go to the
partition the row was read from and give an error otherwise, consisting
of the rows partitioning fields. This will avoid asserts in InnoDB and
also alert the user that there is a misplaced row. A detailed error
message will be given, including an entry to the error log consisting
of both table name, partition and row content (PK if exists, otherwise
all partitioning columns).
2) A new optional syntax for KEY () partitioning in 5.5 is allowed:
[SUB]PARTITION BY KEY [ALGORITHM = N] (list_of_cols)
Where N = 1 uses the same hashing as 5.1 (Numeric/date/time fields uses
binary hashing, ENUM/SET uses charset hashing) N = 2 uses the same
hashing as 5.5 (Numeric/date/time fields uses charset hashing,
ENUM/SET uses binary hashing). If not set on CREATE/ALTER it will
default to 2.
This new syntax should probably be ignored by NDB.
3) Since there is a demand for avoiding scanning through the full
table, during upgrade the ALTER TABLE t PARTITION BY ... command is
considered a no-op (only .frm change) if everything except ALGORITHM
is the same and ALGORITHM was not set before, which allows manually
upgrading such table by something like:
ALTER TABLE t PARTITION BY KEY ALGORITHM = 1 () or
ALTER TABLE t PARTITION BY KEY ALGORITHM = 2 ()
4) Enhanced partitioning with CHECK/REPAIR to also check for/repair
misplaced rows. (Also works for ALTER TABLE t CHECK/REPAIR PARTITION)
CHECK FOR UPGRADE:
If the .frm version is < 5.5.3
and uses KEY [sub]partitioning
and an affected column type
then it will fail with an message:
KEY () partitioning changed, please run:
ALTER TABLE `test`.`t1` PARTITION BY KEY ALGORITHM = 1 (a)
PARTITIONS 12
(i.e. current partitioning clause, with the addition of
ALGORITHM = 1)
CHECK without FOR UPGRADE:
if MEDIUM (default) or EXTENDED options are given:
Scan all rows and verify that it is in the correct partition.
Fail for the first misplaced row.
REPAIR:
if default or EXTENDED (i.e. not QUICK/USE_FRM):
Scan all rows and every misplaced row is moved into its correct
partitions.
5) Updated mysqlcheck (called by mysql_upgrade) to handle the
new output from CHECK FOR UPGRADE, to run the ALTER statement
instead of running REPAIR.
This will allow mysql_upgrade (or CHECK TABLE t FOR UPGRADE) to upgrade
a KEY [sub]partitioned table that has any affected field type
and a .frm version < 5.5.3 to ALGORITHM = 1 without rebuild.
Also notice that if the .frm has a version of >= 5.5.3 and ALGORITHM
is not set, it is not possible to know if it consists of rows from
5.1 or 5.5! In these cases I suggest that the user does:
(optional)
LOCK TABLE t WRITE;
SHOW CREATE TABLE t;
(verify that it has no ALGORITHM = N, and to be safe, I would suggest
backing up the .frm file, to be used if one need to change to another
ALGORITHM = N, without needing to rebuild/repair)
ALTER TABLE t <old partitioning clause, but with ALGORITHM = N>;
which should set the ALGORITHM to N (if the table has rows from
5.1 I would suggest N = 1, otherwise N = 2)
CHECK TABLE t;
(here one could use the backed up .frm instead and change to a new N
and run CHECK again and see if it passes)
and if there are misplaced rows:
REPAIR TABLE t;
(optional)
UNLOCK TABLES;
It was hard to understand what the error really meant.
The error checking in partitioning is done in several different
parts during the execution of a query which can make it
hard to return useful errors.
Added a new error for bad VALUES part in the per PARTITION clause.
Using the more verbose error that a column is not allowed in
the partitioning function instead of just that the function is
not allowed.
into partitioned MyISAM table
Problem was that the ha_data structure was introduced in 5.1
and only used for partitioning first, but with the intention
of be of use for others engines as well, and when used by other
engines it would clash if it also was partitioned.
Solution is to move the partitioning specific data to a separate
structure, with its own mutex (which is used for auto_increment).
Also did rename PARTITION_INFO to PARTITION_STATS since there
already exist a class named partition_info, also cleaned up
some related variables.
Problem was that the partition containing NULL values
was pruned away, since '2001-01-01' < '2001-02-00' but
TO_DAYS('2001-02-00') is NULL.
Added the NULL partition for RANGE/LIST partitioning on TO_DAYS()
function to be scanned too.
Also fixed a bug that added ALLOW_INVALID_DATES to sql_mode
(SELECT * FROM t WHERE date_col < '1999-99-99' on a RANGE/LIST
partitioned table would add it).
added new function test_if_data_home_dir() which checks that
path does not contain mysql data home directory.
Using of 'mysql data home'/'any db name' in
DATA DIRECTORY & INDEX DIRECTORY is disallowed
Problem was that the mix of handlers was not consistent between
CREATE and ALTER
changed so that it works like:
- All partitions must use the same engine
AND it must be the same as the table.
- if one does NOT specify an engine on the table level
then one must either NOT specify any engine on any
partition/subpartition OR for ALL partitions/subpartitions
Note: that after a table have been created, the storage engine
is specified for all parts of the table (table/partition/subpartition)
and so when using alter, one does not need to specify it (unless one
wants to change the storage engine, then one have to specify it on the
table level)
- Introduced val_int_endpoint() function which converts between func
argument intervals and func value intervals for monotonic functions.
- Made partition interval analyzer use part_expr->val_int_endpoint()
to check if the edge values should be included.
causing update of a different column
For efficiency some storage engines do not read a complete record
for update, but only the columns required for selecting the rows.
When updating a row of a partitioned table, modifying a column
that is part of the partition or subpartition expression, then
the row may need to move from one [sub]partition to another one.
This is done by inserting the new row into the target
[sub]partition and deleting the old row from the originating one.
For the insert we need a complete record.
If an above mentioned engine was used for a partitioned table, we
did not have a complete record in update_row(). The implicitly
executed write_row() got an incomplete record.
This is solved by instructing the engine to read a complete record
if one of the columns of the partition or subpartiton is to be
updated.
No testcase. This can be reproduced with Falcon only. The engines
contained in standard 5.1 do always return complete records on
update.
The following type conversions was done:
- Changed byte to uchar
- Changed gptr to uchar*
- Change my_string to char *
- Change my_size_t to size_t
- Change size_s to size_t
Removed declaration of byte, gptr, my_string, my_size_t and size_s.
Following function parameter changes was done:
- All string functions in mysys/strings was changed to use size_t
instead of uint for string lengths.
- All read()/write() functions changed to use size_t (including vio).
- All protocoll functions changed to use size_t instead of uint
- Functions that used a pointer to a string length was changed to use size_t*
- Changed malloc(), free() and related functions from using gptr to use void *
as this requires fewer casts in the code and is more in line with how the
standard functions work.
- Added extra length argument to dirname_part() to return the length of the
created string.
- Changed (at least) following functions to take uchar* as argument:
- db_dump()
- my_net_write()
- net_write_command()
- net_store_data()
- DBUG_DUMP()
- decimal2bin() & bin2decimal()
- Changed my_compress() and my_uncompress() to use size_t. Changed one
argument to my_uncompress() from a pointer to a value as we only return
one value (makes function easier to use).
- Changed type of 'pack_data' argument to packfrm() to avoid casts.
- Changed in readfrm() and writefrom(), ha_discover and handler::discover()
the type for argument 'frmdata' to uchar** to avoid casts.
- Changed most Field functions to use uchar* instead of char* (reduced a lot of
casts).
- Changed field->val_xxx(xxx, new_ptr) to take const pointers.
Other changes:
- Removed a lot of not needed casts
- Added a few new cast required by other changes
- Added some cast to my_multi_malloc() arguments for safety (as string lengths
needs to be uint, not size_t).
- Fixed all calls to hash-get-key functions to use size_t*. (Needed to be done
explicitely as this conflict was often hided by casting the function to
hash_get_key).
- Changed some buffers to memory regions to uchar* to avoid casts.
- Changed some string lengths from uint to size_t.
- Changed field->ptr to be uchar* instead of char*. This allowed us to
get rid of a lot of casts.
- Some changes from true -> TRUE, false -> FALSE, unsigned char -> uchar
- Include zlib.h in some files as we needed declaration of crc32()
- Changed MY_FILE_ERROR to be (size_t) -1.
- Changed many variables to hold the result of my_read() / my_write() to be
size_t. This was needed to properly detect errors (which are
returned as (size_t) -1).
- Removed some very old VMS code
- Changed packfrm()/unpackfrm() to not be depending on uint size
(portability fix)
- Removed windows specific code to restore cursor position as this
causes slowdown on windows and we should not mix read() and pread()
calls anyway as this is not thread safe. Updated function comment to
reflect this. Changed function that depended on original behavior of
my_pwrite() to itself restore the cursor position (one such case).
- Added some missing checking of return value of malloc().
- Changed definition of MOD_PAD_CHAR_TO_FULL_LENGTH to avoid 'long' overflow.
- Changed type of table_def::m_size from my_size_t to ulong to reflect that
m_size is the number of elements in the array, not a string/memory
length.
- Moved THD::max_row_length() to table.cc (as it's not depending on THD).
Inlined max_row_length_blob() into this function.
- More function comments
- Fixed some compiler warnings when compiled without partitions.
- Removed setting of LEX_STRING() arguments in declaration (portability fix).
- Some trivial indentation/variable name changes.
- Some trivial code simplifications:
- Replaced some calls to alloc_root + memcpy to use
strmake_root()/strdup_root().
- Changed some calls from memdup() to strmake() (Safety fix)
- Simpler loops in client-simple.c
the lexer API which internally uses unsigned char variables to
address its state map. The implementation of the lexer should be
internal to the lexer, and not influence the rest of the code.
New methods to handle VARCHAR strings and CHAR's which are not
using a binary collation.
Indentation fixes
Now strings are run through strnxfrm before they are processed
by the partition function
We do not allow collations where strnxfrm expands the string since
we want the resulting string to fit in the same value range as
the original.
Changed test for functions if they are supported.
3 categories:
1) Fully supported
2) Supported for single character collations
3) Supported for binary collations
* Produce right results for conditions that were transformed to "(partitioning_range) AND
(list_of_subpartitioning_ranges)": make each partition id set iterator auto-reset itself
after it has returned all partition ids in the sequence
* Fix "Range mapping" and "Range mapping" partitioning interval analysis functions to
correctly deal with NULL values.
