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mariadb/sql/ha_partition.h
Kent Boortz 0f03af653c Updated/added copyright headers
2011-07-04 01:25:49 +02:00

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#ifndef HA_PARTITION_INCLUDED
#define HA_PARTITION_INCLUDED
/*
Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifdef __GNUC__
#pragma interface /* gcc class implementation */
#endif
#include "sql_partition.h" /* part_id_range, partition_element */
#include "queues.h" /* QUEUE */
enum partition_keywords
{
PKW_HASH= 0, PKW_RANGE, PKW_LIST, PKW_KEY, PKW_MAXVALUE, PKW_LINEAR,
PKW_COLUMNS
};
#define PARTITION_BYTES_IN_POS 2
#define PARTITION_ENABLED_TABLE_FLAGS (HA_FILE_BASED | HA_REC_NOT_IN_SEQ)
#define PARTITION_DISABLED_TABLE_FLAGS (HA_CAN_GEOMETRY | \
HA_CAN_FULLTEXT | \
HA_DUPLICATE_POS | \
HA_CAN_SQL_HANDLER | \
HA_CAN_INSERT_DELAYED)
/* First 4 bytes in the .par file is the number of 32-bit words in the file */
#define PAR_WORD_SIZE 4
/* offset to the .par file checksum */
#define PAR_CHECKSUM_OFFSET 4
/* offset to the total number of partitions */
#define PAR_NUM_PARTS_OFFSET 8
/* offset to the engines array */
#define PAR_ENGINES_OFFSET 12
class ha_partition :public handler
{
private:
enum partition_index_scan_type
{
partition_index_read= 0,
partition_index_first= 1,
partition_index_first_unordered= 2,
partition_index_last= 3,
partition_index_read_last= 4,
partition_read_range = 5,
partition_no_index_scan= 6
};
/* Data for the partition handler */
int m_mode; // Open mode
uint m_open_test_lock; // Open test_if_locked
char *m_file_buffer; // Content of the .par file
char *m_name_buffer_ptr; // Pointer to first partition name
plugin_ref *m_engine_array; // Array of types of the handlers
handler **m_file; // Array of references to handler inst.
uint m_file_tot_parts; // Debug
handler **m_new_file; // Array of references to new handlers
handler **m_reorged_file; // Reorganised partitions
handler **m_added_file; // Added parts kept for errors
partition_info *m_part_info; // local reference to partition
Field **m_part_field_array; // Part field array locally to save acc
uchar *m_ordered_rec_buffer; // Row and key buffer for ord. idx scan
/*
Current index.
When used in key_rec_cmp: If clustered pk, index compare
must compare pk if given index is same for two rows.
So normally m_curr_key_info[0]= current index and m_curr_key[1]= NULL,
and if clustered pk, [0]= current index, [1]= pk, [2]= NULL
*/
KEY *m_curr_key_info[3]; // Current index
uchar *m_rec0; // table->record[0]
QUEUE m_queue; // Prio queue used by sorted read
/*
Since the partition handler is a handler on top of other handlers, it
is necessary to keep information about what the underlying handler
characteristics is. It is not possible to keep any handler instances
for this since the MySQL Server sometimes allocating the handler object
without freeing them.
*/
ulong m_low_byte_first;
enum enum_handler_status
{
handler_not_initialized= 0,
handler_initialized,
handler_opened,
handler_closed
};
enum_handler_status m_handler_status;
uint m_reorged_parts; // Number of reorganised parts
uint m_tot_parts; // Total number of partitions;
uint m_num_locks; // For engines like ha_blackhole, which needs no locks
uint m_last_part; // Last file that we update,write,read
int m_lock_type; // Remembers type of last
// external_lock
part_id_range m_part_spec; // Which parts to scan
uint m_scan_value; // Value passed in rnd_init
// call
uint m_ref_length; // Length of position in this
// handler object
key_range m_start_key; // index read key range
enum partition_index_scan_type m_index_scan_type;// What type of index
// scan
uint m_top_entry; // Which partition is to
// deliver next result
uint m_rec_length; // Local copy of record length
bool m_ordered; // Ordered/Unordered index scan
bool m_pkey_is_clustered; // Is primary key clustered
bool m_create_handler; // Handler used to create table
bool m_is_sub_partitioned; // Is subpartitioned
bool m_ordered_scan_ongoing;
/*
If set, this object was created with ha_partition::clone and doesn't
"own" the m_part_info structure.
*/
ha_partition *m_is_clone_of;
MEM_ROOT *m_clone_mem_root;
/*
We keep track if all underlying handlers are MyISAM since MyISAM has a
great number of extra flags not needed by other handlers.
*/
bool m_myisam; // Are all underlying handlers
// MyISAM
/*
We keep track of InnoDB handlers below since it requires proper setting
of query_id in fields at index_init and index_read calls.
*/
bool m_innodb; // Are all underlying handlers
// InnoDB
/*
When calling extra(HA_EXTRA_CACHE) we do not pass this to the underlying
handlers immediately. Instead we cache it and call the underlying
immediately before starting the scan on the partition. This is to
prevent allocating a READ CACHE for each partition in parallel when
performing a full table scan on MyISAM partitioned table.
This state is cleared by extra(HA_EXTRA_NO_CACHE).
*/
bool m_extra_cache;
uint m_extra_cache_size;
/* The same goes for HA_EXTRA_PREPARE_FOR_UPDATE */
bool m_extra_prepare_for_update;
/* Which partition has active cache */
uint m_extra_cache_part_id;
void init_handler_variables();
/*
Variables for lock structures.
*/
THR_LOCK_DATA lock; /* MySQL lock */
bool auto_increment_lock; /**< lock reading/updating auto_inc */
/**
Flag to keep the auto_increment lock through out the statement.
This to ensure it will work with statement based replication.
*/
bool auto_increment_safe_stmt_log_lock;
/** For optimizing ha_start_bulk_insert calls */
MY_BITMAP m_bulk_insert_started;
ha_rows m_bulk_inserted_rows;
/** used for prediction of start_bulk_insert rows */
enum_monotonicity_info m_part_func_monotonicity_info;
public:
handler *clone(const char *name, MEM_ROOT *mem_root);
virtual void set_part_info(partition_info *part_info)
{
m_part_info= part_info;
m_is_sub_partitioned= part_info->is_sub_partitioned();
}
/*
-------------------------------------------------------------------------
MODULE create/delete handler object
-------------------------------------------------------------------------
Object create/delete methode. The normal called when a table object
exists. There is also a method to create the handler object with only
partition information. This is used from mysql_create_table when the
table is to be created and the engine type is deduced to be the
partition handler.
-------------------------------------------------------------------------
*/
ha_partition(handlerton *hton, TABLE_SHARE * table);
ha_partition(handlerton *hton, partition_info * part_info);
ha_partition(handlerton *hton, TABLE_SHARE *share,
partition_info *part_info_arg,
ha_partition *clone_arg,
MEM_ROOT *clone_mem_root_arg);
~ha_partition();
/*
A partition handler has no characteristics in itself. It only inherits
those from the underlying handlers. Here we set-up those constants to
enable later calls of the methods to retrieve constants from the under-
lying handlers. Returns false if not successful.
*/
bool initialize_partition(MEM_ROOT *mem_root);
/*
-------------------------------------------------------------------------
MODULE meta data changes
-------------------------------------------------------------------------
Meta data routines to CREATE, DROP, RENAME table and often used at
ALTER TABLE (update_create_info used from ALTER TABLE and SHOW ..).
update_table_comment is used in SHOW TABLE commands to provide a
chance for the handler to add any interesting comments to the table
comments not provided by the users comment.
create_handler_files is called before opening a new handler object
with openfrm to call create. It is used to create any local handler
object needed in opening the object in openfrm
-------------------------------------------------------------------------
*/
virtual int delete_table(const char *from);
virtual int rename_table(const char *from, const char *to);
virtual int create(const char *name, TABLE *form,
HA_CREATE_INFO *create_info);
virtual int create_handler_files(const char *name,
const char *old_name, int action_flag,
HA_CREATE_INFO *create_info);
virtual void update_create_info(HA_CREATE_INFO *create_info);
virtual char *update_table_comment(const char *comment);
virtual int change_partitions(HA_CREATE_INFO *create_info,
const char *path,
ulonglong * const copied,
ulonglong * const deleted,
const uchar *pack_frm_data,
size_t pack_frm_len);
virtual int drop_partitions(const char *path);
virtual int rename_partitions(const char *path);
bool get_no_parts(const char *name, uint *num_parts)
{
DBUG_ENTER("ha_partition::get_no_parts");
*num_parts= m_tot_parts;
DBUG_RETURN(0);
}
virtual void change_table_ptr(TABLE *table_arg, TABLE_SHARE *share);
virtual bool check_if_incompatible_data(HA_CREATE_INFO *create_info,
uint table_changes);
private:
int prepare_for_rename();
int copy_partitions(ulonglong * const copied, ulonglong * const deleted);
void cleanup_new_partition(uint part_count);
int prepare_new_partition(TABLE *table, HA_CREATE_INFO *create_info,
handler *file, const char *part_name,
partition_element *p_elem);
/*
delete_table, rename_table and create uses very similar logic which
is packed into this routine.
*/
uint del_ren_cre_table(const char *from, const char *to,
TABLE *table_arg, HA_CREATE_INFO *create_info);
/*
One method to create the table_name.par file containing the names of the
underlying partitions, their engine and the number of partitions.
And one method to read it in.
*/
bool create_handler_file(const char *name);
bool setup_engine_array(MEM_ROOT *mem_root);
bool read_par_file(const char *name);
bool get_from_handler_file(const char *name, MEM_ROOT *mem_root,
bool is_clone);
bool new_handlers_from_part_info(MEM_ROOT *mem_root);
bool create_handlers(MEM_ROOT *mem_root);
void clear_handler_file();
int set_up_table_before_create(TABLE *table_arg,
const char *partition_name_with_path,
HA_CREATE_INFO *info,
uint part_id,
partition_element *p_elem);
partition_element *find_partition_element(uint part_id);
public:
/*
-------------------------------------------------------------------------
MODULE open/close object
-------------------------------------------------------------------------
Open and close handler object to ensure all underlying files and
objects allocated and deallocated for query handling is handled
properly.
-------------------------------------------------------------------------
A handler object is opened as part of its initialisation and before
being used for normal queries (not before meta-data changes always.
If the object was opened it will also be closed before being deleted.
*/
virtual int open(const char *name, int mode, uint test_if_locked);
virtual int close(void);
/*
-------------------------------------------------------------------------
MODULE start/end statement
-------------------------------------------------------------------------
This module contains methods that are used to understand start/end of
statements, transaction boundaries, and aid for proper concurrency
control.
The partition handler need not implement abort and commit since this
will be handled by any underlying handlers implementing transactions.
There is only one call to each handler type involved per transaction
and these go directly to the handlers supporting transactions
currently InnoDB, BDB and NDB).
-------------------------------------------------------------------------
*/
virtual THR_LOCK_DATA **store_lock(THD * thd, THR_LOCK_DATA ** to,
enum thr_lock_type lock_type);
virtual int external_lock(THD * thd, int lock_type);
/*
When table is locked a statement is started by calling start_stmt
instead of external_lock
*/
virtual int start_stmt(THD * thd, thr_lock_type lock_type);
/*
Lock count is number of locked underlying handlers (I assume)
*/
virtual uint lock_count(void) const;
/*
Call to unlock rows not to be updated in transaction
*/
virtual void unlock_row();
/*
Check if semi consistent read
*/
virtual bool was_semi_consistent_read();
/*
Call to hint about semi consistent read
*/
virtual void try_semi_consistent_read(bool);
/*
-------------------------------------------------------------------------
MODULE change record
-------------------------------------------------------------------------
This part of the handler interface is used to change the records
after INSERT, DELETE, UPDATE, REPLACE method calls but also other
special meta-data operations as ALTER TABLE, LOAD DATA, TRUNCATE.
-------------------------------------------------------------------------
These methods are used for insert (write_row), update (update_row)
and delete (delete_row). All methods to change data always work on
one row at a time. update_row and delete_row also contains the old
row.
delete_all_rows will delete all rows in the table in one call as a
special optimisation for DELETE from table;
Bulk inserts are supported if all underlying handlers support it.
start_bulk_insert and end_bulk_insert is called before and after a
number of calls to write_row.
*/
virtual int write_row(uchar * buf);
virtual int update_row(const uchar * old_data, uchar * new_data);
virtual int delete_row(const uchar * buf);
virtual int delete_all_rows(void);
virtual int truncate();
virtual void start_bulk_insert(ha_rows rows);
virtual int end_bulk_insert();
private:
ha_rows guess_bulk_insert_rows();
void start_part_bulk_insert(THD *thd, uint part_id);
long estimate_read_buffer_size(long original_size);
public:
/*
Method for truncating a specific partition.
(i.e. ALTER TABLE t1 TRUNCATE PARTITION p).
@remark This method is a partitioning-specific hook
and thus not a member of the general SE API.
*/
int truncate_partition(Alter_info *, bool *binlog_stmt);
virtual bool is_fatal_error(int error, uint flags)
{
if (!handler::is_fatal_error(error, flags) ||
error == HA_ERR_NO_PARTITION_FOUND)
return FALSE;
return TRUE;
}
/*
-------------------------------------------------------------------------
MODULE full table scan
-------------------------------------------------------------------------
This module is used for the most basic access method for any table
handler. This is to fetch all data through a full table scan. No
indexes are needed to implement this part.
It contains one method to start the scan (rnd_init) that can also be
called multiple times (typical in a nested loop join). Then proceeding
to the next record (rnd_next) and closing the scan (rnd_end).
To remember a record for later access there is a method (position)
and there is a method used to retrieve the record based on the stored
position.
The position can be a file position, a primary key, a ROWID dependent
on the handler below.
-------------------------------------------------------------------------
*/
/*
unlike index_init(), rnd_init() can be called two times
without rnd_end() in between (it only makes sense if scan=1).
then the second call should prepare for the new table scan
(e.g if rnd_init allocates the cursor, second call should
position it to the start of the table, no need to deallocate
and allocate it again
*/
virtual int rnd_init(bool scan);
virtual int rnd_end();
virtual int rnd_next(uchar * buf);
virtual int rnd_pos(uchar * buf, uchar * pos);
virtual int rnd_pos_by_record(uchar *record);
virtual void position(const uchar * record);
/*
-------------------------------------------------------------------------
MODULE index scan
-------------------------------------------------------------------------
This part of the handler interface is used to perform access through
indexes. The interface is defined as a scan interface but the handler
can also use key lookup if the index is a unique index or a primary
key index.
Index scans are mostly useful for SELECT queries but are an important
part also of UPDATE, DELETE, REPLACE and CREATE TABLE table AS SELECT
and so forth.
Naturally an index is needed for an index scan and indexes can either
be ordered, hash based. Some ordered indexes can return data in order
but not necessarily all of them.
There are many flags that define the behavior of indexes in the
various handlers. These methods are found in the optimizer module.
-------------------------------------------------------------------------
index_read is called to start a scan of an index. The find_flag defines
the semantics of the scan. These flags are defined in
include/my_base.h
index_read_idx is the same but also initializes index before calling doing
the same thing as index_read. Thus it is similar to index_init followed
by index_read. This is also how we implement it.
index_read/index_read_idx does also return the first row. Thus for
key lookups, the index_read will be the only call to the handler in
the index scan.
index_init initializes an index before using it and index_end does
any end processing needed.
*/
virtual int index_read_map(uchar * buf, const uchar * key,
key_part_map keypart_map,
enum ha_rkey_function find_flag);
virtual int index_init(uint idx, bool sorted);
virtual int index_end();
/**
@breif
Positions an index cursor to the index specified in the hanlde. Fetches the
row if available. If the key value is null, begin at first key of the
index.
*/
virtual int index_read_idx_map(uchar *buf, uint index, const uchar *key,
key_part_map keypart_map,
enum ha_rkey_function find_flag);
/*
These methods are used to jump to next or previous entry in the index
scan. There are also methods to jump to first and last entry.
*/
virtual int index_next(uchar * buf);
virtual int index_prev(uchar * buf);
virtual int index_first(uchar * buf);
virtual int index_last(uchar * buf);
virtual int index_next_same(uchar * buf, const uchar * key, uint keylen);
virtual int index_read_last_map(uchar * buf, const uchar * key,
key_part_map keypart_map);
/*
read_first_row is virtual method but is only implemented by
handler.cc, no storage engine has implemented it so neither
will the partition handler.
virtual int read_first_row(uchar *buf, uint primary_key);
*/
/*
We don't implement multi read range yet, will do later.
virtual int read_multi_range_first(KEY_MULTI_RANGE **found_range_p,
KEY_MULTI_RANGE *ranges, uint range_count,
bool sorted, HANDLER_BUFFER *buffer);
virtual int read_multi_range_next(KEY_MULTI_RANGE **found_range_p);
*/
virtual int read_range_first(const key_range * start_key,
const key_range * end_key,
bool eq_range, bool sorted);
virtual int read_range_next();
private:
int common_index_read(uchar * buf, bool have_start_key);
int common_first_last(uchar * buf);
int partition_scan_set_up(uchar * buf, bool idx_read_flag);
int handle_unordered_next(uchar * buf, bool next_same);
int handle_unordered_scan_next_partition(uchar * buf);
uchar *queue_buf(uint part_id)
{
return (m_ordered_rec_buffer +
(part_id * (m_rec_length + PARTITION_BYTES_IN_POS)));
}
uchar *rec_buf(uint part_id)
{
return (queue_buf(part_id) +
PARTITION_BYTES_IN_POS);
}
int handle_ordered_index_scan(uchar * buf, bool reverse_order);
int handle_ordered_next(uchar * buf, bool next_same);
int handle_ordered_prev(uchar * buf);
void return_top_record(uchar * buf);
void column_bitmaps_signal();
public:
/*
-------------------------------------------------------------------------
MODULE information calls
-------------------------------------------------------------------------
This calls are used to inform the handler of specifics of the ongoing
scans and other actions. Most of these are used for optimisation
purposes.
-------------------------------------------------------------------------
*/
virtual int info(uint);
void get_dynamic_partition_info(PARTITION_STATS *stat_info,
uint part_id);
virtual int extra(enum ha_extra_function operation);
virtual int extra_opt(enum ha_extra_function operation, ulong cachesize);
virtual int reset(void);
private:
static const uint NO_CURRENT_PART_ID;
int loop_extra(enum ha_extra_function operation);
void late_extra_cache(uint partition_id);
void late_extra_no_cache(uint partition_id);
void prepare_extra_cache(uint cachesize);
public:
/*
-------------------------------------------------------------------------
MODULE optimiser support
-------------------------------------------------------------------------
-------------------------------------------------------------------------
*/
/*
NOTE !!!!!!
-------------------------------------------------------------------------
-------------------------------------------------------------------------
One important part of the public handler interface that is not depicted in
the methods is the attribute records
which is defined in the base class. This is looked upon directly and is
set by calling info(HA_STATUS_INFO) ?
-------------------------------------------------------------------------
*/
private:
/*
Helper function to get the minimum number of partitions to use for
the optimizer hints/cost calls.
*/
void partitions_optimizer_call_preparations(uint *num_used_parts,
uint *check_min_num,
uint *first);
ha_rows estimate_rows(bool is_records_in_range, uint inx,
key_range *min_key, key_range *max_key);
public:
/*
keys_to_use_for_scanning can probably be implemented as the
intersection of all underlying handlers if mixed handlers are used.
This method is used to derive whether an index can be used for
index-only scanning when performing an ORDER BY query.
Only called from one place in sql_select.cc
*/
virtual const key_map *keys_to_use_for_scanning();
/*
Called in test_quick_select to determine if indexes should be used.
*/
virtual double scan_time();
/*
The next method will never be called if you do not implement indexes.
*/
virtual double read_time(uint index, uint ranges, ha_rows rows);
/*
For the given range how many records are estimated to be in this range.
Used by optimiser to calculate cost of using a particular index.
*/
virtual ha_rows records_in_range(uint inx, key_range * min_key,
key_range * max_key);
/*
Upper bound of number records returned in scan is sum of all
underlying handlers.
*/
virtual ha_rows estimate_rows_upper_bound();
/*
table_cache_type is implemented by the underlying handler but all
underlying handlers must have the same implementation for it to work.
*/
virtual uint8 table_cache_type();
virtual ha_rows records();
/*
-------------------------------------------------------------------------
MODULE print messages
-------------------------------------------------------------------------
This module contains various methods that returns text messages for
table types, index type and error messages.
-------------------------------------------------------------------------
*/
/*
The name of the index type that will be used for display
Here we must ensure that all handlers use the same index type
for each index created.
*/
virtual const char *index_type(uint inx);
/* The name of the table type that will be used for display purposes */
virtual const char *table_type() const;
/* The name of the row type used for the underlying tables. */
virtual enum row_type get_row_type() const;
/*
Handler specific error messages
*/
virtual void print_error(int error, myf errflag);
virtual bool get_error_message(int error, String * buf);
/*
-------------------------------------------------------------------------
MODULE handler characteristics
-------------------------------------------------------------------------
This module contains a number of methods defining limitations and
characteristics of the handler. The partition handler will calculate
this characteristics based on underlying handler characteristics.
-------------------------------------------------------------------------
This is a list of flags that says what the storage engine
implements. The current table flags are documented in handler.h
The partition handler will support whatever the underlying handlers
support except when specifically mentioned below about exceptions
to this rule.
NOTE: This cannot be cached since it can depend on TRANSACTION ISOLATION
LEVEL which is dynamic, see bug#39084.
HA_READ_RND_SAME:
Not currently used. (Means that the handler supports the rnd_same() call)
(MyISAM, HEAP)
HA_TABLE_SCAN_ON_INDEX:
Used to avoid scanning full tables on an index. If this flag is set then
the handler always has a primary key (hidden if not defined) and this
index is used for scanning rather than a full table scan in all
situations.
(InnoDB, BDB, Federated)
HA_REC_NOT_IN_SEQ:
This flag is set for handlers that cannot guarantee that the rows are
returned accroding to incremental positions (0, 1, 2, 3...).
This also means that rnd_next() should return HA_ERR_RECORD_DELETED
if it finds a deleted row.
(MyISAM (not fixed length row), BDB, HEAP, NDB, InooDB)
HA_CAN_GEOMETRY:
Can the storage engine handle spatial data.
Used to check that no spatial attributes are declared unless
the storage engine is capable of handling it.
(MyISAM)
HA_FAST_KEY_READ:
Setting this flag indicates that the handler is equally fast in
finding a row by key as by position.
This flag is used in a very special situation in conjunction with
filesort's. For further explanation see intro to init_read_record.
(BDB, HEAP, InnoDB)
HA_NULL_IN_KEY:
Is NULL values allowed in indexes.
If this is not allowed then it is not possible to use an index on a
NULLable field.
(BDB, HEAP, MyISAM, NDB, InnoDB)
HA_DUPLICATE_POS:
Tells that we can the position for the conflicting duplicate key
record is stored in table->file->dupp_ref. (insert uses rnd_pos() on
this to find the duplicated row)
(MyISAM)
HA_CAN_INDEX_BLOBS:
Is the storage engine capable of defining an index of a prefix on
a BLOB attribute.
(BDB, Federated, MyISAM, InnoDB)
HA_AUTO_PART_KEY:
Auto increment fields can be part of a multi-part key. For second part
auto-increment keys, the auto_incrementing is done in handler.cc
(BDB, Federated, MyISAM, NDB)
HA_REQUIRE_PRIMARY_KEY:
Can't define a table without primary key (and cannot handle a table
with hidden primary key)
(No handler has this limitation currently)
HA_STATS_RECORDS_IS_EXACT:
Does the counter of records after the info call specify an exact
value or not. If it does this flag is set.
Only MyISAM and HEAP uses exact count.
HA_CAN_INSERT_DELAYED:
Can the storage engine support delayed inserts.
To start with the partition handler will not support delayed inserts.
Further investigation needed.
(HEAP, MyISAM)
HA_PRIMARY_KEY_IN_READ_INDEX:
This parameter is set when the handler will also return the primary key
when doing read-only-key on another index.
HA_NOT_DELETE_WITH_CACHE:
Seems to be an old MyISAM feature that is no longer used. No handler
has it defined but it is checked in init_read_record.
Further investigation needed.
(No handler defines it)
HA_NO_PREFIX_CHAR_KEYS:
Indexes on prefixes of character fields is not allowed.
(NDB)
HA_CAN_FULLTEXT:
Does the storage engine support fulltext indexes
The partition handler will start by not supporting fulltext indexes.
(MyISAM)
HA_CAN_SQL_HANDLER:
Can the HANDLER interface in the MySQL API be used towards this
storage engine.
(MyISAM, InnoDB)
HA_NO_AUTO_INCREMENT:
Set if the storage engine does not support auto increment fields.
(Currently not set by any handler)
HA_HAS_CHECKSUM:
Special MyISAM feature. Has special SQL support in CREATE TABLE.
No special handling needed by partition handler.
(MyISAM)
HA_FILE_BASED:
Should file names always be in lower case (used by engines
that map table names to file names.
Since partition handler has a local file this flag is set.
(BDB, Federated, MyISAM)
HA_CAN_BIT_FIELD:
Is the storage engine capable of handling bit fields?
(MyISAM, NDB)
HA_NEED_READ_RANGE_BUFFER:
Is Read Multi-Range supported => need multi read range buffer
This parameter specifies whether a buffer for read multi range
is needed by the handler. Whether the handler supports this
feature or not is dependent of whether the handler implements
read_multi_range* calls or not. The only handler currently
supporting this feature is NDB so the partition handler need
not handle this call. There are methods in handler.cc that will
transfer those calls into index_read and other calls in the
index scan module.
(NDB)
HA_PRIMARY_KEY_REQUIRED_FOR_POSITION:
Does the storage engine need a PK for position?
(InnoDB)
HA_FILE_BASED is always set for partition handler since we use a
special file for handling names of partitions, engine types.
HA_REC_NOT_IN_SEQ is always set for partition handler since we cannot
guarantee that the records will be returned in sequence.
HA_CAN_GEOMETRY, HA_CAN_FULLTEXT, HA_CAN_SQL_HANDLER, HA_DUPLICATE_POS,
HA_CAN_INSERT_DELAYED, HA_PRIMARY_KEY_REQUIRED_FOR_POSITION is disabled
until further investigated.
*/
virtual Table_flags table_flags() const
{
DBUG_ENTER("ha_partition::table_flags");
if (m_handler_status < handler_initialized ||
m_handler_status >= handler_closed)
DBUG_RETURN(PARTITION_ENABLED_TABLE_FLAGS);
DBUG_RETURN((m_file[0]->ha_table_flags() &
~(PARTITION_DISABLED_TABLE_FLAGS)) |
(PARTITION_ENABLED_TABLE_FLAGS));
}
/*
This is a bitmap of flags that says how the storage engine
implements indexes. The current index flags are documented in
handler.h. If you do not implement indexes, just return zero
here.
part is the key part to check. First key part is 0
If all_parts it's set, MySQL want to know the flags for the combined
index up to and including 'part'.
HA_READ_NEXT:
Does the index support read next, this is assumed in the server
code and never checked so all indexes must support this.
Note that the handler can be used even if it doesn't have any index.
(BDB, HEAP, MyISAM, Federated, NDB, InnoDB)
HA_READ_PREV:
Can the index be used to scan backwards.
(BDB, HEAP, MyISAM, NDB, InnoDB)
HA_READ_ORDER:
Can the index deliver its record in index order. Typically true for
all ordered indexes and not true for hash indexes.
In first step this is not true for partition handler until a merge
sort has been implemented in partition handler.
Used to set keymap part_of_sortkey
This keymap is only used to find indexes usable for resolving an ORDER BY
in the query. Thus in most cases index_read will work just fine without
order in result production. When this flag is set it is however safe to
order all output started by index_read since most engines do this. With
read_multi_range calls there is a specific flag setting order or not
order so in those cases ordering of index output can be avoided.
(BDB, InnoDB, HEAP, MyISAM, NDB)
HA_READ_RANGE:
Specify whether index can handle ranges, typically true for all
ordered indexes and not true for hash indexes.
Used by optimiser to check if ranges (as key >= 5) can be optimised
by index.
(BDB, InnoDB, NDB, MyISAM, HEAP)
HA_ONLY_WHOLE_INDEX:
Can't use part key searches. This is typically true for hash indexes
and typically not true for ordered indexes.
(Federated, NDB, HEAP)
HA_KEYREAD_ONLY:
Does the storage engine support index-only scans on this index.
Enables use of HA_EXTRA_KEYREAD and HA_EXTRA_NO_KEYREAD
Used to set key_map keys_for_keyread and to check in optimiser for
index-only scans. When doing a read under HA_EXTRA_KEYREAD the handler
only have to fill in the columns the key covers. If
HA_PRIMARY_KEY_IN_READ_INDEX is set then also the PRIMARY KEY columns
must be updated in the row.
(BDB, InnoDB, MyISAM)
*/
virtual ulong index_flags(uint inx, uint part, bool all_parts) const
{
return m_file[0]->index_flags(inx, part, all_parts);
}
/**
wrapper function for handlerton alter_table_flags, since
the ha_partition_hton cannot know all its capabilities
*/
virtual uint alter_table_flags(uint flags);
/*
extensions of table handler files
*/
virtual const char **bas_ext() const;
/*
unireg.cc will call the following to make sure that the storage engine
can handle the data it is about to send.
The maximum supported values is the minimum of all handlers in the table
*/
uint min_of_the_max_uint(uint (handler::*operator_func)(void) const) const;
virtual uint max_supported_record_length() const;
virtual uint max_supported_keys() const;
virtual uint max_supported_key_parts() const;
virtual uint max_supported_key_length() const;
virtual uint max_supported_key_part_length() const;
/*
All handlers in a partitioned table must have the same low_byte_first
*/
virtual bool low_byte_first() const
{ return m_low_byte_first; }
/*
The extra record buffer length is the maximum needed by all handlers.
The minimum record length is the maximum of all involved handlers.
*/
virtual uint extra_rec_buf_length() const;
virtual uint min_record_length(uint options) const;
/*
Primary key is clustered can only be true if all underlying handlers have
this feature.
*/
virtual bool primary_key_is_clustered()
{ return m_pkey_is_clustered; }
/*
-------------------------------------------------------------------------
MODULE compare records
-------------------------------------------------------------------------
cmp_ref checks if two references are the same. For most handlers this is
a simple memcmp of the reference. However some handlers use primary key
as reference and this can be the same even if memcmp says they are
different. This is due to character sets and end spaces and so forth.
For the partition handler the reference is first two bytes providing the
partition identity of the referred record and then the reference of the
underlying handler.
Thus cmp_ref for the partition handler always returns FALSE for records
not in the same partition and uses cmp_ref on the underlying handler
to check whether the rest of the reference part is also the same.
-------------------------------------------------------------------------
*/
virtual int cmp_ref(const uchar * ref1, const uchar * ref2);
/*
-------------------------------------------------------------------------
MODULE auto increment
-------------------------------------------------------------------------
This module is used to handle the support of auto increments.
This variable in the handler is used as part of the handler interface
It is maintained by the parent handler object and should not be
touched by child handler objects (see handler.cc for its use).
auto_increment_column_changed
-------------------------------------------------------------------------
*/
virtual void get_auto_increment(ulonglong offset, ulonglong increment,
ulonglong nb_desired_values,
ulonglong *first_value,
ulonglong *nb_reserved_values);
virtual void release_auto_increment();
private:
virtual int reset_auto_increment(ulonglong value);
virtual void lock_auto_increment()
{
/* lock already taken */
if (auto_increment_safe_stmt_log_lock)
return;
DBUG_ASSERT(table_share->ha_part_data && !auto_increment_lock);
if(table_share->tmp_table == NO_TMP_TABLE)
{
auto_increment_lock= TRUE;
mysql_mutex_lock(&table_share->ha_part_data->LOCK_auto_inc);
}
}
virtual void unlock_auto_increment()
{
DBUG_ASSERT(table_share->ha_part_data);
/*
If auto_increment_safe_stmt_log_lock is true, we have to keep the lock.
It will be set to false and thus unlocked at the end of the statement by
ha_partition::release_auto_increment.
*/
if(auto_increment_lock && !auto_increment_safe_stmt_log_lock)
{
mysql_mutex_unlock(&table_share->ha_part_data->LOCK_auto_inc);
auto_increment_lock= FALSE;
}
}
virtual void set_auto_increment_if_higher(Field *field)
{
ulonglong nr= (((Field_num*) field)->unsigned_flag ||
field->val_int() > 0) ? field->val_int() : 0;
lock_auto_increment();
DBUG_ASSERT(table_share->ha_part_data->auto_inc_initialized == TRUE);
/* must check when the mutex is taken */
if (nr >= table_share->ha_part_data->next_auto_inc_val)
table_share->ha_part_data->next_auto_inc_val= nr + 1;
unlock_auto_increment();
}
public:
/*
-------------------------------------------------------------------------
MODULE initialize handler for HANDLER call
-------------------------------------------------------------------------
This method is a special InnoDB method called before a HANDLER query.
-------------------------------------------------------------------------
*/
virtual void init_table_handle_for_HANDLER();
/*
The remainder of this file defines the handler methods not implemented
by the partition handler
*/
/*
-------------------------------------------------------------------------
MODULE foreign key support
-------------------------------------------------------------------------
The following methods are used to implement foreign keys as supported by
InnoDB. Implement this ??
get_foreign_key_create_info is used by SHOW CREATE TABLE to get a textual
description of how the CREATE TABLE part to define FOREIGN KEY's is done.
free_foreign_key_create_info is used to free the memory area that provided
this description.
can_switch_engines checks if it is ok to switch to a new engine based on
the foreign key info in the table.
-------------------------------------------------------------------------
virtual char* get_foreign_key_create_info()
virtual void free_foreign_key_create_info(char* str)
virtual int get_foreign_key_list(THD *thd,
List<FOREIGN_KEY_INFO> *f_key_list)
virtual uint referenced_by_foreign_key()
*/
virtual bool can_switch_engines();
/*
-------------------------------------------------------------------------
MODULE fulltext index
-------------------------------------------------------------------------
Fulltext stuff not yet.
-------------------------------------------------------------------------
virtual int ft_init() { return HA_ERR_WRONG_COMMAND; }
virtual FT_INFO *ft_init_ext(uint flags,uint inx,const uchar *key,
uint keylen)
{ return NULL; }
virtual int ft_read(uchar *buf) { return HA_ERR_WRONG_COMMAND; }
*/
/*
-------------------------------------------------------------------------
MODULE restart full table scan at position (MyISAM)
-------------------------------------------------------------------------
The following method is only used by MyISAM when used as
temporary tables in a join.
virtual int restart_rnd_next(uchar *buf, uchar *pos);
*/
/*
-------------------------------------------------------------------------
MODULE on-line ALTER TABLE
-------------------------------------------------------------------------
These methods are in the handler interface. (used by innodb-plugin)
They are used for on-line/fast alter table add/drop index:
-------------------------------------------------------------------------
*/
virtual int add_index(TABLE *table_arg, KEY *key_info, uint num_of_keys,
handler_add_index **add);
virtual int final_add_index(handler_add_index *add, bool commit);
virtual int prepare_drop_index(TABLE *table_arg, uint *key_num,
uint num_of_keys);
virtual int final_drop_index(TABLE *table_arg);
/*
-------------------------------------------------------------------------
MODULE tablespace support
-------------------------------------------------------------------------
Admin of table spaces is not applicable to the partition handler (InnoDB)
This means that the following method is not implemented:
-------------------------------------------------------------------------
virtual int discard_or_import_tablespace(my_bool discard)
*/
/*
-------------------------------------------------------------------------
MODULE admin MyISAM
-------------------------------------------------------------------------
-------------------------------------------------------------------------
OPTIMIZE TABLE, CHECK TABLE, ANALYZE TABLE and REPAIR TABLE are
mapped to a routine that handles looping over a given set of
partitions and those routines send a flag indicating to execute on
all partitions.
-------------------------------------------------------------------------
*/
virtual int optimize(THD* thd, HA_CHECK_OPT *check_opt);
virtual int analyze(THD* thd, HA_CHECK_OPT *check_opt);
virtual int check(THD* thd, HA_CHECK_OPT *check_opt);
virtual int repair(THD* thd, HA_CHECK_OPT *check_opt);
virtual bool check_and_repair(THD *thd);
virtual bool auto_repair() const;
virtual bool is_crashed() const;
private:
int handle_opt_partitions(THD *thd, HA_CHECK_OPT *check_opt, uint flags);
public:
/*
-------------------------------------------------------------------------
Admin commands not supported currently (almost purely MyISAM routines)
This means that the following methods are not implemented:
-------------------------------------------------------------------------
virtual int backup(TD* thd, HA_CHECK_OPT *check_opt);
virtual int restore(THD* thd, HA_CHECK_OPT *check_opt);
virtual int dump(THD* thd, int fd = -1);
virtual int net_read_dump(NET* net);
virtual uint checksum() const;
*/
/* Enabled keycache for performance reasons, WL#4571 */
virtual int assign_to_keycache(THD* thd, HA_CHECK_OPT *check_opt);
virtual int preload_keys(THD* thd, HA_CHECK_OPT* check_opt);
/*
-------------------------------------------------------------------------
MODULE enable/disable indexes
-------------------------------------------------------------------------
Enable/Disable Indexes are only supported by HEAP and MyISAM.
-------------------------------------------------------------------------
*/
virtual int disable_indexes(uint mode);
virtual int enable_indexes(uint mode);
virtual int indexes_are_disabled(void);
/*
-------------------------------------------------------------------------
MODULE append_create_info
-------------------------------------------------------------------------
append_create_info is only used by MyISAM MERGE tables and the partition
handler will not support this handler as underlying handler.
Implement this??
-------------------------------------------------------------------------
virtual void append_create_info(String *packet)
*/
};
#endif /* HA_PARTITION_INCLUDED */
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