mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-16 20:12:31 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions
mariadb/sql/ha_partition.cc
unknown a59351e562 Makefile.am: 
Distribute "handlerton-win.cc"
mysqld.cc:
  Corrected word lenght for some innobase
  configuration variables
Makefile.am:
  Added Visual Studio 7 project file to EXTRA_DIST
ha_partition.cc, sql_partition.cc:
  Changed include to use "..." for Windows
handlerton-win.cc:
  Handle engine include/exclude with defines for Windows
  new file


sql/handlerton-win.cc:
  Handle engine include/exclude with defines for Windows
sql/sql_partition.cc:
  Changed include to use "..." for Windows
sql/ha_partition.cc:
  Changed include to use "..." for Windows
extra/yassl/Makefile.am:
  Added Visual Studio 7 project file to EXTRA_DIST
extra/yassl/taocrypt/Makefile.am:
  Added Visual Studio 7 project file to EXTRA_DIST
sql/mysqld.cc:
  Corrected word lenght for some innobase
  configuration variables
sql/Makefile.am:
  Distribute "handlerton-win.cc"
2005-11-26 05:35:37 +01:00

3270 lines
98 KiB
C++
Raw Blame History

/* Copyright (C) 2005 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
This handler was developed by Mikael Ronstrom for version 5.1 of MySQL.
It is an abstraction layer on top of other handlers such as MyISAM,
InnoDB, Federated, Berkeley DB and so forth. Partitioned tables can also
be handled by a storage engine. The current example of this is NDB
Cluster that has internally handled partitioning. This have benefits in
that many loops needed in the partition handler can be avoided.
Partitioning has an inherent feature which in some cases is positive and
in some cases is negative. It splits the data into chunks. This makes
the data more manageable, queries can easily be parallelised towards the
parts and indexes are split such that there are less levels in the
index trees. The inherent disadvantage is that to use a split index
one has to scan all index parts which is ok for large queries but for
small queries it can be a disadvantage.
Partitioning lays the foundation for more manageable databases that are
extremely large. It does also lay the foundation for more parallelism
in the execution of queries. This functionality will grow with later
versions of MySQL.
You can enable it in your buld by doing the following during your build
process:
./configure --with-partition
The partition is setup to use table locks. It implements an partition "SHARE"
that is inserted into a hash by table name. You can use this to store
information of state that any partition handler object will be able to see
if it is using the same table.
Please read the object definition in ha_partition.h before reading the rest
if this file.
*/
#ifdef __GNUC__
#pragma implementation // gcc: Class implementation
#endif
#include "mysql_priv.h"
#include "ha_partition.h"
static const char *ha_par_ext= ".par";
#ifdef NOT_USED
static int free_share(PARTITION_SHARE * share);
static PARTITION_SHARE *get_share(const char *table_name, TABLE * table);
#endif
/****************************************************************************
MODULE create/delete handler object
****************************************************************************/
static handler *partition_create_handler(TABLE_SHARE *share);
handlerton partition_hton = {
"partition",
SHOW_OPTION_YES,
"Partition Storage Engine Helper", /* A comment used by SHOW to describe an engine */
DB_TYPE_PARTITION_DB,
0, /* Method that initializes a storage engine */
0, /* slot */
0, /* savepoint size */
NULL /*ndbcluster_close_connection*/,
NULL, /* savepoint_set */
NULL, /* savepoint_rollback */
NULL, /* savepoint_release */
NULL /*ndbcluster_commit*/,
NULL /*ndbcluster_rollback*/,
NULL, /* prepare */
NULL, /* recover */
NULL, /* commit_by_xid */
NULL, /* rollback_by_xid */
NULL,
NULL,
NULL,
partition_create_handler, /* Create a new handler */
NULL, /* Drop a database */
NULL, /* Panic call */
NULL, /* Release temporary latches */
NULL, /* Update Statistics */
NULL, /* Start Consistent Snapshot */
NULL, /* Flush logs */
NULL, /* Show status */
NULL, /* Replication Report Sent Binlog */
HTON_NOT_USER_SELECTABLE
};
static handler *partition_create_handler(TABLE_SHARE *share)
{
return new ha_partition(share);
}
ha_partition::ha_partition(TABLE_SHARE *share)
:handler(&partition_hton, share), m_part_info(NULL), m_create_handler(FALSE),
m_is_sub_partitioned(0)
{
DBUG_ENTER("ha_partition::ha_partition(table)");
init_handler_variables();
DBUG_VOID_RETURN;
}
ha_partition::ha_partition(partition_info *part_info)
:handler(&partition_hton, NULL), m_part_info(part_info),
m_create_handler(TRUE),
m_is_sub_partitioned(is_sub_partitioned(m_part_info))
{
DBUG_ENTER("ha_partition::ha_partition(part_info)");
init_handler_variables();
DBUG_ASSERT(m_part_info);
DBUG_VOID_RETURN;
}
void ha_partition::init_handler_variables()
{
active_index= MAX_KEY;
m_file_buffer= NULL;
m_name_buffer_ptr= NULL;
m_engine_array= NULL;
m_file= NULL;
m_tot_parts= 0;
m_has_transactions= 0;
m_pkey_is_clustered= 0;
m_lock_type= F_UNLCK;
m_part_spec.start_part= NO_CURRENT_PART_ID;
m_scan_value= 2;
m_ref_length= 0;
m_part_spec.end_part= NO_CURRENT_PART_ID;
m_index_scan_type= partition_no_index_scan;
m_start_key.key= NULL;
m_start_key.length= 0;
m_myisam= FALSE;
m_innodb= FALSE;
m_extra_cache= FALSE;
m_extra_cache_size= 0;
m_table_flags= HA_FILE_BASED | HA_REC_NOT_IN_SEQ;
m_low_byte_first= 1;
m_part_field_array= NULL;
m_ordered_rec_buffer= NULL;
m_top_entry= NO_CURRENT_PART_ID;
m_rec_length= 0;
m_last_part= 0;
m_rec0= 0;
m_curr_key_info= 0;
/*
this allows blackhole to work properly
*/
m_no_locks= 0;
#ifdef DONT_HAVE_TO_BE_INITALIZED
m_start_key.flag= 0;
m_ordered= TRUE;
#endif
}
ha_partition::~ha_partition()
{
DBUG_ENTER("ha_partition::~ha_partition()");
if (m_file != NULL)
{
uint i;
for (i= 0; i < m_tot_parts; i++)
delete m_file[i];
}
my_free((char*) m_ordered_rec_buffer, MYF(MY_ALLOW_ZERO_PTR));
clear_handler_file();
DBUG_VOID_RETURN;
}
/*
The partition handler is only a layer on top of other engines. Thus it
can't really perform anything without the underlying handlers. Thus we
add this method as part of the allocation of a handler object.
1) Allocation of underlying handlers
If we have access to the partition info we will allocate one handler
instance for each partition.
2) Allocation without partition info
The cases where we don't have access to this information is when called
in preparation for delete_table and rename_table and in that case we
only need to set HA_FILE_BASED. In that case we will use the .par file
that contains information about the partitions and their engines and
the names of each partition.
3) Table flags initialisation
We need also to set table flags for the partition handler. This is not
static since it depends on what storage engines are used as underlying
handlers.
The table flags is set in this routine to simulate the behaviour of a
normal storage engine
The flag HA_FILE_BASED will be set independent of the underlying handlers
4) Index flags initialisation
When knowledge exists on the indexes it is also possible to initialise the
index flags. Again the index flags must be initialised by using the under-
lying handlers since this is storage engine dependent.
The flag HA_READ_ORDER will be reset for the time being to indicate no
ordered output is available from partition handler indexes. Later a merge
sort will be performed using the underlying handlers.
5) primary_key_is_clustered, has_transactions and low_byte_first is
calculated here.
*/
int ha_partition::ha_initialise()
{
handler **file_array, *file;
DBUG_ENTER("ha_partition::ha_initialise");
if (m_create_handler)
{
m_tot_parts= get_tot_partitions(m_part_info);
DBUG_ASSERT(m_tot_parts > 0);
if (new_handlers_from_part_info())
DBUG_RETURN(1);
}
else if (!table_share || !table_share->normalized_path.str)
{
/*
Called with dummy table share (delete, rename and alter table)
Don't need to set-up table flags other than
HA_FILE_BASED here
*/
m_table_flags|= HA_FILE_BASED | HA_REC_NOT_IN_SEQ;
DBUG_RETURN(0);
}
else if (get_from_handler_file(table_share->normalized_path.str))
{
my_error(ER_OUTOFMEMORY, MYF(0), 129); //Temporary fix TODO print_error
DBUG_RETURN(1);
}
/*
We create all underlying table handlers here. We do it in this special
method to be able to report allocation errors.
Set up table_flags, low_byte_first, primary_key_is_clustered and
has_transactions since they are called often in all kinds of places,
other parameters are calculated on demand.
HA_FILE_BASED is always set for partition handler since we use a
special file for handling names of partitions, engine types.
HA_CAN_GEOMETRY, HA_CAN_FULLTEXT, HA_CAN_SQL_HANDLER,
HA_CAN_INSERT_DELAYED is disabled until further investigated.
*/
m_table_flags= m_file[0]->table_flags();
m_low_byte_first= m_file[0]->low_byte_first();
m_has_transactions= TRUE;
m_pkey_is_clustered= TRUE;
file_array= m_file;
do
{
file= *file_array;
if (m_low_byte_first != file->low_byte_first())
{
// Cannot have handlers with different endian
my_error(ER_MIX_HANDLER_ERROR, MYF(0));
DBUG_RETURN(1);
}
if (!file->has_transactions())
m_has_transactions= FALSE;
if (!file->primary_key_is_clustered())
m_pkey_is_clustered= FALSE;
m_table_flags&= file->table_flags();
} while (*(++file_array));
m_table_flags&= ~(HA_CAN_GEOMETRY & HA_CAN_FULLTEXT &
HA_CAN_SQL_HANDLER & HA_CAN_INSERT_DELAYED);
m_table_flags|= HA_FILE_BASED | HA_REC_NOT_IN_SEQ;
DBUG_RETURN(0);
}
/****************************************************************************
MODULE meta data changes
****************************************************************************/
/*
This method is used to calculate the partition name, service routine to
the del_ren_cre_table method.
*/
static void create_partition_name(char *out, const char *in1, const char *in2)
{
strxmov(out, in1, "_", in2, NullS);
}
/*
This method is used to calculate the partition name, service routine to
the del_ren_cre_table method.
*/
static void create_subpartition_name(char *out, const char *in1,
const char *in2, const char *in3)
{
strxmov(out, in1, "_", in2, "_", in3, NullS);
}
/*
Used to delete a table. By the time delete_table() has been called all
opened references to this table will have been closed (and your globally
shared references released. The variable name will just be the name of
the table. You will need to remove any files you have created at this
point.
If you do not implement this, the default delete_table() is called from
handler.cc and it will delete all files with the file extentions returned
by bas_ext().
Called from handler.cc by delete_table and ha_create_table(). Only used
during create if the table_flag HA_DROP_BEFORE_CREATE was specified for
the storage engine.
*/
int ha_partition::delete_table(const char *name)
{
int error;
DBUG_ENTER("ha_partition::delete_table");
if ((error= del_ren_cre_table(name, NULL, NULL, NULL)))
DBUG_RETURN(error);
DBUG_RETURN(handler::delete_table(name));
}
/*
Renames a table from one name to another from alter table call.
If you do not implement this, the default rename_table() is called from
handler.cc and it will delete all files with the file extentions returned
by bas_ext().
Called from sql_table.cc by mysql_rename_table().
*/
int ha_partition::rename_table(const char *from, const char *to)
{
int error;
DBUG_ENTER("ha_partition::rename_table");
if ((error= del_ren_cre_table(from, to, NULL, NULL)))
DBUG_RETURN(error);
DBUG_RETURN(handler::rename_table(from, to));
}
/*
create_handler_files is called to create any handler specific files
before opening the file with openfrm to later call ::create on the
file object.
In the partition handler this is used to store the names of partitions
and types of engines in the partitions.
*/
int ha_partition::create_handler_files(const char *name)
{
DBUG_ENTER("ha_partition::create_handler_files()");
/*
We need to update total number of parts since we might write the handler
file as part of a partition management command
*/
m_tot_parts= get_tot_partitions(m_part_info);
if (create_handler_file(name))
{
my_error(ER_CANT_CREATE_HANDLER_FILE, MYF(0));
DBUG_RETURN(1);
}
DBUG_RETURN(0);
}
/*
create() is called to create a table. The variable name will have the name
of the table. When create() is called you do not need to worry about
opening the table. Also, the FRM file will have already been created so
adjusting create_info will not do you any good. You can overwrite the frm
file at this point if you wish to change the table definition, but there
are no methods currently provided for doing that.
Called from handle.cc by ha_create_table().
*/
int ha_partition::create(const char *name, TABLE *table_arg,
HA_CREATE_INFO *create_info)
{
char t_name[FN_REFLEN];
DBUG_ENTER("ha_partition::create");
strmov(t_name, name);
*fn_ext(t_name)= 0;
if (del_ren_cre_table(t_name, NULL, table_arg, create_info))
{
handler::delete_table(t_name);
DBUG_RETURN(1);
}
DBUG_RETURN(0);
}
int ha_partition::drop_partitions(const char *path)
{
List_iterator<partition_element> part_it(m_part_info->partitions);
char part_name_buff[FN_REFLEN];
uint no_parts= m_part_info->no_parts;
uint no_subparts= m_part_info->no_subparts, i= 0;
int error= 1;
DBUG_ENTER("ha_partition::drop_partitions()");
do
{
partition_element *part_elem= part_it++;
if (part_elem->part_state == PART_IS_DROPPED)
{
/*
This part is to be dropped, meaning the part or all its subparts.
*/
if (is_sub_partitioned(m_part_info))
{
List_iterator<partition_element> sub_it(part_elem->subpartitions);
uint j= 0, part;
do
{
partition_element *sub_elem= sub_it++;
create_subpartition_name(part_name_buff, path,
part_elem->partition_name,
sub_elem->partition_name);
part= i * no_subparts + j;
DBUG_PRINT("info", ("Drop subpartition %s", part_name_buff));
error= m_file[part]->delete_table((const char *) part_name_buff);
} while (++j < no_subparts);
}
else
{
create_partition_name(part_name_buff, path,
part_elem->partition_name);
DBUG_PRINT("info", ("Drop partition %s", part_name_buff));
error= m_file[i]->delete_table((const char *) part_name_buff);
}
}
} while (++i < no_parts);
DBUG_RETURN(error);
}
void ha_partition::update_create_info(HA_CREATE_INFO *create_info)
{
return;
}
char *ha_partition::update_table_comment(const char *comment)
{
return (char*) comment; // Nothing to change
}
/*
Common routine to handle delete_table and rename_table.
The routine uses the partition handler file to get the
names of the partition instances. Both these routines
are called after creating the handler without table
object and thus the file is needed to discover the
names of the partitions and the underlying storage engines.
*/
uint ha_partition::del_ren_cre_table(const char *from,
const char *to,
TABLE *table_arg,
HA_CREATE_INFO *create_info)
{
int save_error= 0, error;
char from_buff[FN_REFLEN], to_buff[FN_REFLEN];
char *name_buffer_ptr;
uint i;
handler **file;
DBUG_ENTER("del_ren_cre_table()");
if (get_from_handler_file(from))
DBUG_RETURN(TRUE);
DBUG_ASSERT(m_file_buffer);
name_buffer_ptr= m_name_buffer_ptr;
file= m_file;
i= 0;
do
{
create_partition_name(from_buff, from, name_buffer_ptr);
if (to != NULL)
{ // Rename branch
create_partition_name(to_buff, to, name_buffer_ptr);
error= (*file)->rename_table((const char*) from_buff,
(const char*) to_buff);
}
else if (table_arg == NULL) // delete branch
error= (*file)->delete_table((const char*) from_buff);
else
{
set_up_table_before_create(table_arg, create_info, i);
error= (*file)->create(from_buff, table_arg, create_info);
}
name_buffer_ptr= strend(name_buffer_ptr) + 1;
if (error)
save_error= error;
i++;
} while (*(++file));
DBUG_RETURN(save_error);
}
partition_element *ha_partition::find_partition_element(uint part_id)
{
uint i;
uint curr_part_id= 0;
List_iterator_fast < partition_element > part_it(m_part_info->partitions);
for (i= 0; i < m_part_info->no_parts; i++)
{
partition_element *part_elem;
part_elem= part_it++;
if (m_is_sub_partitioned)
{
uint j;
List_iterator_fast <partition_element> sub_it(part_elem->subpartitions);
for (j= 0; j < m_part_info->no_subparts; j++)
{
part_elem= sub_it++;
if (part_id == curr_part_id++)
return part_elem;
}
}
else if (part_id == curr_part_id++)
return part_elem;
}
DBUG_ASSERT(0);
current_thd->fatal_error(); // Abort
return NULL;
}
void ha_partition::set_up_table_before_create(TABLE *table,
HA_CREATE_INFO *info,
uint part_id)
{
/*
Set up
1) Comment on partition
2) MAX_ROWS, MIN_ROWS on partition
3) Index file name on partition
4) Data file name on partition
*/
partition_element *part_elem= find_partition_element(part_id);
if (!part_elem)
return; // Fatal error
table->s->max_rows= part_elem->part_max_rows;
table->s->min_rows= part_elem->part_min_rows;
info->index_file_name= part_elem->index_file_name;
info->data_file_name= part_elem->data_file_name;
}
/*
Routine used to add two names with '_' in between then. Service routine
to create_handler_file
Include the NULL in the count of characters since it is needed as separator
between the partition names.
*/
static uint name_add(char *dest, const char *first_name, const char *sec_name)
{
return (uint) (strxmov(dest, first_name, "_", sec_name, NullS) -dest) + 1;
}
/*
Method used to create handler file with names of partitions, their
engine types and the number of partitions.
*/
bool ha_partition::create_handler_file(const char *name)
{
partition_element *part_elem, *subpart_elem;
uint i, j, part_name_len, subpart_name_len;
uint tot_partition_words, tot_name_len;
uint tot_len_words, tot_len_byte, chksum, tot_name_words;
char *name_buffer_ptr;
uchar *file_buffer, *engine_array;
bool result= TRUE;
char file_name[FN_REFLEN];
File file;
List_iterator_fast < partition_element > part_it(m_part_info->partitions);
DBUG_ENTER("create_handler_file");
DBUG_PRINT("info", ("table name = %s", name));
tot_name_len= 0;
for (i= 0; i < m_part_info->no_parts; i++)
{
part_elem= part_it++;
part_name_len= strlen(part_elem->partition_name);
if (!m_is_sub_partitioned)
tot_name_len+= part_name_len + 1;
else
{
List_iterator_fast<partition_element> sub_it(part_elem->subpartitions);
for (j= 0; j < m_part_info->no_subparts; j++)
{
subpart_elem= sub_it++;
subpart_name_len= strlen(subpart_elem->partition_name);
tot_name_len+= part_name_len + subpart_name_len + 2;
}
}
}
/*
File format:
Length in words 4 byte
Checksum 4 byte
Total number of partitions 4 byte
Array of engine types n * 4 bytes where
n = (m_tot_parts + 3)/4
Length of name part in bytes 4 bytes
Name part m * 4 bytes where
m = ((length_name_part + 3)/4)*4
All padding bytes are zeroed
*/
tot_partition_words= (m_tot_parts + 3) / 4;
tot_name_words= (tot_name_len + 3) / 4;
tot_len_words= 4 + tot_partition_words + tot_name_words;
tot_len_byte= 4 * tot_len_words;
if (!(file_buffer= (uchar *) my_malloc(tot_len_byte, MYF(MY_ZEROFILL))))
DBUG_RETURN(TRUE);
engine_array= (file_buffer + 12);
name_buffer_ptr= (char*) (file_buffer + ((4 + tot_partition_words) * 4));
part_it.rewind();
for (i= 0; i < m_part_info->no_parts; i++)
{
part_elem= part_it++;
if (!m_is_sub_partitioned)
{
name_buffer_ptr= strmov(name_buffer_ptr, part_elem->partition_name)+1;
*engine_array= (uchar) part_elem->engine_type;
DBUG_PRINT("info", ("engine: %u", *engine_array));
engine_array++;
}
else
{
List_iterator_fast<partition_element> sub_it(part_elem->subpartitions);
for (j= 0; j < m_part_info->no_subparts; j++)
{
subpart_elem= sub_it++;
name_buffer_ptr+= name_add(name_buffer_ptr,
part_elem->partition_name,
subpart_elem->partition_name);
*engine_array= (uchar) part_elem->engine_type;
engine_array++;
}
}
}
chksum= 0;
int4store(file_buffer, tot_len_words);
int4store(file_buffer + 8, m_tot_parts);
int4store(file_buffer + 12 + (tot_partition_words * 4), tot_name_len);
for (i= 0; i < tot_len_words; i++)
chksum^= uint4korr(file_buffer + 4 * i);
int4store(file_buffer + 4, chksum);
/*
Remove .frm extension and replace with .par
Create and write and close file
to be used at open, delete_table and rename_table
*/
fn_format(file_name, name, "", ".par", MYF(MY_REPLACE_EXT));
if ((file= my_create(file_name, CREATE_MODE, O_RDWR | O_TRUNC,
MYF(MY_WME))) >= 0)
{
result= my_write(file, (byte *) file_buffer, tot_len_byte,
MYF(MY_WME | MY_NABP));
VOID(my_close(file, MYF(0)));
}
else
result= TRUE;
my_free((char*) file_buffer, MYF(0));
DBUG_RETURN(result);
}
void ha_partition::clear_handler_file()
{
my_free((char*) m_file_buffer, MYF(MY_ALLOW_ZERO_PTR));
m_file_buffer= NULL;
m_name_buffer_ptr= NULL;
m_engine_array= NULL;
}
bool ha_partition::create_handlers()
{
uint i;
uint alloc_len= (m_tot_parts + 1) * sizeof(handler*);
DBUG_ENTER("create_handlers");
if (!(m_file= (handler **) sql_alloc(alloc_len)))
DBUG_RETURN(TRUE);
bzero(m_file, alloc_len);
for (i= 0; i < m_tot_parts; i++)
{
if (!(m_file[i]= get_new_handler(table_share, current_thd->mem_root,
(enum db_type) m_engine_array[i])))
DBUG_RETURN(TRUE);
DBUG_PRINT("info", ("engine_type: %u", m_engine_array[i]));
}
m_file[m_tot_parts]= 0;
/* For the moment we only support partition over the same table engine */
if (m_engine_array[0] == (uchar) DB_TYPE_MYISAM)
{
DBUG_PRINT("info", ("MyISAM"));
m_myisam= TRUE;
}
else if (m_engine_array[0] == (uchar) DB_TYPE_INNODB)
{
DBUG_PRINT("info", ("InnoDB"));
m_innodb= TRUE;
}
DBUG_RETURN(FALSE);
}
bool ha_partition::new_handlers_from_part_info()
{
uint i, j;
partition_element *part_elem;
uint alloc_len= (m_tot_parts + 1) * sizeof(handler*);
List_iterator_fast <partition_element> part_it(m_part_info->partitions);
THD *thd= current_thd;
DBUG_ENTER("ha_partition::new_handlers_from_part_info");
if (!(m_file= (handler **) sql_alloc(alloc_len)))
goto error;
bzero(m_file, alloc_len);
DBUG_ASSERT(m_part_info->no_parts > 0);
i= 0;
/*
Don't know the size of the underlying storage engine, invent a number of
bytes allocated for error message if allocation fails
*/
alloc_len= 128;
do
{
part_elem= part_it++;
if (!(m_file[i]= get_new_handler(table_share, thd->mem_root,
part_elem->engine_type)))
goto error;
DBUG_PRINT("info", ("engine_type: %u", (uint) part_elem->engine_type));
if (m_is_sub_partitioned)
{
for (j= 0; j < m_part_info->no_subparts; j++)
{
if (!(m_file[i]= get_new_handler(table_share, thd->mem_root,
part_elem->engine_type)))
goto error;
DBUG_PRINT("info", ("engine_type: %u", (uint) part_elem->engine_type));
}
}
} while (++i < m_part_info->no_parts);
if (part_elem->engine_type == DB_TYPE_MYISAM)
{
DBUG_PRINT("info", ("MyISAM"));
m_myisam= TRUE;
}
DBUG_RETURN(FALSE);
error:
my_error(ER_OUTOFMEMORY, MYF(0), alloc_len);
DBUG_RETURN(TRUE);
}
/*
Open handler file to get partition names, engine types and number of
partitions.
*/
bool ha_partition::get_from_handler_file(const char *name)
{
char buff[FN_REFLEN], *address_tot_name_len;
File file;
char *file_buffer, *name_buffer_ptr;
uchar *engine_array;
uint i, len_bytes, len_words, tot_partition_words, tot_name_words, chksum;
DBUG_ENTER("ha_partition::get_from_handler_file");
DBUG_PRINT("enter", ("table name: '%s'", name));
if (m_file_buffer)
DBUG_RETURN(FALSE);
fn_format(buff, name, "", ha_par_ext, MYF(0));
/* Following could be done with my_stat to read in whole file */
if ((file= my_open(buff, O_RDONLY | O_SHARE, MYF(0))) < 0)
DBUG_RETURN(TRUE);
if (my_read(file, (byte *) & buff[0], 8, MYF(MY_NABP)))
goto err1;
len_words= uint4korr(buff);
len_bytes= 4 * len_words;
if (!(file_buffer= my_malloc(len_bytes, MYF(0))))
goto err1;
VOID(my_seek(file, 0, MY_SEEK_SET, MYF(0)));
if (my_read(file, (byte *) file_buffer, len_bytes, MYF(MY_NABP)))
goto err2;
chksum= 0;
for (i= 0; i < len_words; i++)
chksum ^= uint4korr((file_buffer) + 4 * i);
if (chksum)
goto err2;
m_tot_parts= uint4korr((file_buffer) + 8);
tot_partition_words= (m_tot_parts + 3) / 4;
engine_array= (uchar *) ((file_buffer) + 12);
address_tot_name_len= file_buffer + 12 + 4 * tot_partition_words;
tot_name_words= (uint4korr(address_tot_name_len) + 3) / 4;
if (len_words != (tot_partition_words + tot_name_words + 4))
goto err2;
name_buffer_ptr= file_buffer + 16 + 4 * tot_partition_words;
VOID(my_close(file, MYF(0)));
m_file_buffer= file_buffer; // Will be freed in clear_handler_file()
m_name_buffer_ptr= name_buffer_ptr;
m_engine_array= engine_array;
if (!m_file && create_handlers())
{
clear_handler_file();
DBUG_RETURN(TRUE);
}
DBUG_RETURN(FALSE);
err2:
my_free(file_buffer, MYF(0));
err1:
VOID(my_close(file, MYF(0)));
DBUG_RETURN(TRUE);
}
/****************************************************************************
MODULE open/close object
****************************************************************************/
/*
Used for opening tables. The name will be the name of the file.
A table is opened when it needs to be opened. For instance
when a request comes in for a select on the table (tables are not
open and closed for each request, they are cached).
Called from handler.cc by handler::ha_open(). The server opens all tables
by calling ha_open() which then calls the handler specific open().
*/
int ha_partition::open(const char *name, int mode, uint test_if_locked)
{
int error;
char name_buff[FN_REFLEN];
char *name_buffer_ptr= m_name_buffer_ptr;
handler **file;
uint alloc_len;
DBUG_ENTER("ha_partition::open");
ref_length= 0;
m_part_field_array= m_part_info->full_part_field_array;
if (get_from_handler_file(name))
DBUG_RETURN(1);
m_start_key.length= 0;
m_rec0= table->record[0];
m_rec_length= table->s->reclength;
alloc_len= m_tot_parts * (m_rec_length + PARTITION_BYTES_IN_POS);
alloc_len+= table->s->max_key_length;
if (!m_ordered_rec_buffer)
{
if (!(m_ordered_rec_buffer= (byte*)my_malloc(alloc_len, MYF(MY_WME))))
{
DBUG_RETURN(1);
}
{
/*
We set-up one record per partition and each record has 2 bytes in
front where the partition id is written. This is used by ordered
index_read.
We also set-up a reference to the first record for temporary use in
setting up the scan.
*/
char *ptr= (char*)m_ordered_rec_buffer;
uint i= 0;
do
{
int2store(ptr, i);
ptr+= m_rec_length + PARTITION_BYTES_IN_POS;
} while (++i < m_tot_parts);
m_start_key.key= (const byte*)ptr;
}
}
file= m_file;
do
{
create_partition_name(name_buff, name, name_buffer_ptr);
if ((error= (*file)->ha_open(table, (const char*) name_buff, mode,
test_if_locked)))
goto err_handler;
m_no_locks+= (*file)->lock_count();
name_buffer_ptr+= strlen(name_buffer_ptr) + 1;
set_if_bigger(ref_length, ((*file)->ref_length));
} while (*(++file));
/*
Add 2 bytes for partition id in position ref length.
ref_length=max_in_all_partitions(ref_length) + PARTITION_BYTES_IN_POS
*/
ref_length+= PARTITION_BYTES_IN_POS;
m_ref_length= ref_length;
/*
Release buffer read from .par file. It will not be reused again after
being opened once.
*/
clear_handler_file();
/*
Initialise priority queue, initialised to reading forward.
*/
if ((error= init_queue(&queue, m_tot_parts, (uint) PARTITION_BYTES_IN_POS,
0, key_rec_cmp, (void*)this)))
goto err_handler;
/*
Some handlers update statistics as part of the open call. This will in
some cases corrupt the statistics of the partition handler and thus
to ensure we have correct statistics we call info from open after
calling open on all individual handlers.
*/
info(HA_STATUS_VARIABLE | HA_STATUS_CONST);
DBUG_RETURN(0);
err_handler:
while (file-- != m_file)
(*file)->close();
DBUG_RETURN(error);
}
/*
Closes a table. We call the free_share() function to free any resources
that we have allocated in the "shared" structure.
Called from sql_base.cc, sql_select.cc, and table.cc.
In sql_select.cc it is only used to close up temporary tables or during
the process where a temporary table is converted over to being a
myisam table.
For sql_base.cc look at close_data_tables().
*/
int ha_partition::close(void)
{
handler **file;
DBUG_ENTER("ha_partition::close");
delete_queue(&queue);
file= m_file;
do
{
(*file)->close();
} while (*(++file));
DBUG_RETURN(0);
}
/****************************************************************************
MODULE start/end statement
****************************************************************************/
/*
A number of methods to define various constants for the handler. In
the case of the partition handler we need to use some max and min
of the underlying handlers in most cases.
*/
/*
First you should go read the section "locking functions for mysql" in
lock.cc to understand this.
This create a lock on the table. If you are implementing a storage engine
that can handle transactions look at ha_berkely.cc to see how you will
want to goo about doing this. Otherwise you should consider calling
flock() here.
Originally this method was used to set locks on file level to enable
several MySQL Servers to work on the same data. For transactional
engines it has been "abused" to also mean start and end of statements
to enable proper rollback of statements and transactions. When LOCK
TABLES has been issued the start_stmt method takes over the role of
indicating start of statement but in this case there is no end of
statement indicator(?).
Called from lock.cc by lock_external() and unlock_external(). Also called
from sql_table.cc by copy_data_between_tables().
*/
int ha_partition::external_lock(THD *thd, int lock_type)
{
uint error;
handler **file;
DBUG_ENTER("ha_partition::external_lock");
file= m_file;
do
{
if ((error= (*file)->external_lock(thd, lock_type)))
{
if (lock_type != F_UNLCK)
goto err_handler;
}
} while (*(++file));
m_lock_type= lock_type; // For the future (2009?)
DBUG_RETURN(0);
err_handler:
while (file-- != m_file)
(*file)->external_lock(thd, F_UNLCK);
DBUG_RETURN(error);
}
/*
The idea with handler::store_lock() is the following:
The statement decided which locks we should need for the table
for updates/deletes/inserts we get WRITE locks, for SELECT... we get
read locks.
Before adding the lock into the table lock handler (see thr_lock.c)
mysqld calls store lock with the requested locks. Store lock can now
modify a write lock to a read lock (or some other lock), ignore the
lock (if we don't want to use MySQL table locks at all) or add locks
for many tables (like we do when we are using a MERGE handler).
Berkeley DB for partition changes all WRITE locks to TL_WRITE_ALLOW_WRITE
(which signals that we are doing WRITES, but we are still allowing other
reader's and writer's.
When releasing locks, store_lock() are also called. In this case one
usually doesn't have to do anything.
store_lock is called when holding a global mutex to ensure that only
one thread at a time changes the locking information of tables.
In some exceptional cases MySQL may send a request for a TL_IGNORE;
This means that we are requesting the same lock as last time and this
should also be ignored. (This may happen when someone does a flush
table when we have opened a part of the tables, in which case mysqld
closes and reopens the tables and tries to get the same locks at last
time). In the future we will probably try to remove this.
Called from lock.cc by get_lock_data().
*/
THR_LOCK_DATA **ha_partition::store_lock(THD *thd,
THR_LOCK_DATA **to,
enum thr_lock_type lock_type)
{
handler **file;
DBUG_ENTER("ha_partition::store_lock");
file= m_file;
do
{
to= (*file)->store_lock(thd, to, lock_type);
} while (*(++file));
DBUG_RETURN(to);
}
int ha_partition::start_stmt(THD *thd, thr_lock_type lock_type)
{
int error= 0;
handler **file;
DBUG_ENTER("ha_partition::start_stmt");
file= m_file;
do
{
if ((error= (*file)->start_stmt(thd, lock_type)))
break;
} while (*(++file));
DBUG_RETURN(error);
}
/*
Returns the number of store locks needed in call to store lock.
We return number of partitions since we call store_lock on each
underlying handler. Assists the above functions in allocating
sufficient space for lock structures.
*/
uint ha_partition::lock_count() const
{
DBUG_ENTER("ha_partition::lock_count");
DBUG_RETURN(m_no_locks);
}
/*
Record currently processed was not in the result set of the statement
and is thus unlocked. Used for UPDATE and DELETE queries.
*/
void ha_partition::unlock_row()
{
m_file[m_last_part]->unlock_row();
return;
}
/****************************************************************************
MODULE change record
****************************************************************************/
/*
write_row() inserts a row. buf() is a byte array of data, normally record[0].
You can use the field information to extract the data from the native byte
array type.
Example of this would be:
for (Field **field=table->field ; *field ; field++)
{
...
}
See ha_tina.cc for an partition of extracting all of the data as strings.
ha_berekly.cc has an partition of how to store it intact by "packing" it
for ha_berkeley's own native storage type.
See the note for update_row() on auto_increments and timestamps. This
case also applied to write_row().
Called from item_sum.cc, item_sum.cc, sql_acl.cc, sql_insert.cc,
sql_insert.cc, sql_select.cc, sql_table.cc, sql_udf.cc, and sql_update.cc.
ADDITIONAL INFO:
Most handlers set timestamp when calling write row if any such fields
exists. Since we are calling an underlying handler we assume the
underlying handler will assume this responsibility.
Underlying handlers will also call update_auto_increment to calculate
the new auto increment value. We will catch the call to
get_auto_increment and ensure this increment value is maintained by
only one of the underlying handlers.
*/
int ha_partition::write_row(byte * buf)
{
uint32 part_id;
int error;
#ifdef NOT_NEEDED
byte *rec0= m_rec0;
#endif
DBUG_ENTER("ha_partition::write_row");
DBUG_ASSERT(buf == m_rec0);
#ifdef NOT_NEEDED
if (likely(buf == rec0))
#endif
error= m_part_info->get_partition_id(m_part_info, &part_id);
#ifdef NOT_NEEDED
else
{
set_field_ptr(m_part_field_array, buf, rec0);
error= m_part_info->get_partition_id(m_part_info, &part_id);
set_field_ptr(m_part_field_array, rec0, buf);
}
#endif
if (unlikely(error))
DBUG_RETURN(error);
m_last_part= part_id;
DBUG_PRINT("info", ("Insert in partition %d", part_id));
DBUG_RETURN(m_file[part_id]->write_row(buf));
}
/*
Yes, update_row() does what you expect, it updates a row. old_data will
have the previous row record in it, while new_data will have the newest
data in it.
Keep in mind that the server can do updates based on ordering if an
ORDER BY clause was used. Consecutive ordering is not guarenteed.
Currently new_data will not have an updated auto_increament record, or
and updated timestamp field. You can do these for partition by doing these:
if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_UPDATE)
table->timestamp_field->set_time();
if (table->next_number_field && record == table->record[0])
update_auto_increment();
Called from sql_select.cc, sql_acl.cc, sql_update.cc, and sql_insert.cc.
new_data is always record[0]
old_data is normally record[1] but may be anything
*/
int ha_partition::update_row(const byte *old_data, byte *new_data)
{
uint32 new_part_id, old_part_id;
int error;
DBUG_ENTER("ha_partition::update_row");
if ((error= get_parts_for_update(old_data, new_data, table->record[0],
m_part_info, &old_part_id, &new_part_id)))
{
DBUG_RETURN(error);
}
/*
TODO:
set_internal_auto_increment=
max(set_internal_auto_increment, new_data->auto_increment)
*/
m_last_part= new_part_id;
if (new_part_id == old_part_id)
{
DBUG_PRINT("info", ("Update in partition %d", new_part_id));
DBUG_RETURN(m_file[new_part_id]->update_row(old_data, new_data));
}
else
{
DBUG_PRINT("info", ("Update from partition %d to partition %d",
old_part_id, new_part_id));
if ((error= m_file[new_part_id]->write_row(new_data)))
DBUG_RETURN(error);
if ((error= m_file[old_part_id]->delete_row(old_data)))
{
#ifdef IN_THE_FUTURE
(void) m_file[new_part_id]->delete_last_inserted_row(new_data);
#endif
DBUG_RETURN(error);
}
}
DBUG_RETURN(0);
}
/*
This will delete a row. buf will contain a copy of the row to be deleted.
The server will call this right after the current row has been read
(from either a previous rnd_xxx() or index_xxx() call).
If you keep a pointer to the last row or can access a primary key it will
make doing the deletion quite a bit easier.
Keep in mind that the server does no guarentee consecutive deletions.
ORDER BY clauses can be used.
Called in sql_acl.cc and sql_udf.cc to manage internal table information.
Called in sql_delete.cc, sql_insert.cc, and sql_select.cc. In sql_select
it is used for removing duplicates while in insert it is used for REPLACE
calls.
buf is either record[0] or record[1]
*/
int ha_partition::delete_row(const byte *buf)
{
uint32 part_id;
int error;
DBUG_ENTER("ha_partition::delete_row");
if ((error= get_part_for_delete(buf, m_rec0, m_part_info, &part_id)))
{
DBUG_RETURN(error);
}
m_last_part= part_id;
DBUG_RETURN(m_file[part_id]->delete_row(buf));
}
/*
Used to delete all rows in a table. Both for cases of truncate and
for cases where the optimizer realizes that all rows will be
removed as a result of a SQL statement.
Called from item_sum.cc by Item_func_group_concat::clear(),
Item_sum_count_distinct::clear(), and Item_func_group_concat::clear().
Called from sql_delete.cc by mysql_delete().
Called from sql_select.cc by JOIN::reinit().
Called from sql_union.cc by st_select_lex_unit::exec().
*/
int ha_partition::delete_all_rows()
{
int error;
handler **file;
DBUG_ENTER("ha_partition::delete_all_rows");
file= m_file;
do
{
if ((error= (*file)->delete_all_rows()))
DBUG_RETURN(error);
} while (*(++file));
DBUG_RETURN(0);
}
/*
rows == 0 means we will probably insert many rows
*/
void ha_partition::start_bulk_insert(ha_rows rows)
{
handler **file;
DBUG_ENTER("ha_partition::start_bulk_insert");
if (!rows)
{
/* Avoid allocation big caches in all underlaying handlers */
DBUG_VOID_RETURN;
}
rows= rows/m_tot_parts + 1;
file= m_file;
do
{
(*file)->start_bulk_insert(rows);
} while (*(++file));
DBUG_VOID_RETURN;
}
int ha_partition::end_bulk_insert()
{
int error= 0;
handler **file;
DBUG_ENTER("ha_partition::end_bulk_insert");
file= m_file;
do
{
int tmp;
/* We want to execute end_bulk_insert() on all handlers */
if ((tmp= (*file)->end_bulk_insert()))
error= tmp;
} while (*(++file));
DBUG_RETURN(error);
}
/****************************************************************************
MODULE full table scan
****************************************************************************/
/*
Initialize engine for random reads
SYNOPSIS
ha_partition::rnd_init()
scan 0 Initialize for random reads through rnd_pos()
1 Initialize for random scan through rnd_next()
NOTES
rnd_init() is called when the server wants the storage engine to do a
table scan or when the server wants to access data through rnd_pos.
When scan is used we will scan one handler partition at a time.
When preparing for rnd_pos we will init all handler partitions.
No extra cache handling is needed when scannning is not performed.
Before initialising we will call rnd_end to ensure that we clean up from
any previous incarnation of a table scan.
Called from filesort.cc, records.cc, sql_handler.cc, sql_select.cc,
sql_table.cc, and sql_update.cc.
*/
int ha_partition::rnd_init(bool scan)
{
int error;
handler **file;
DBUG_ENTER("ha_partition::rnd_init");
include_partition_fields_in_used_fields();
if (scan)
{
/*
rnd_end() is needed for partitioning to reset internal data if scan
is already in use
*/
rnd_end();
if (partition_scan_set_up(rec_buf(0), FALSE))
{
/*
The set of partitions to scan is empty. We return success and return
end of file on first rnd_next.
*/
DBUG_RETURN(0);
}
/*
We will use the partition set in our scan, using the start and stop
partition and checking each scan before start dependent on bittfields.
*/
late_extra_cache(m_part_spec.start_part);
DBUG_PRINT("info", ("rnd_init on partition %d",m_part_spec.start_part));
error= m_file[m_part_spec.start_part]->ha_rnd_init(1);
m_scan_value= 1; // Scan active
if (error)
m_scan_value= 2; // No scan active
DBUG_RETURN(error);
}
file= m_file;
do
{
if ((error= (*file)->ha_rnd_init(0)))
goto err;
} while (*(++file));
m_scan_value= 0;
DBUG_RETURN(0);
err:
while (file--)
(*file)->ha_rnd_end();
DBUG_RETURN(error);
}
int ha_partition::rnd_end()
{
handler **file;
DBUG_ENTER("ha_partition::rnd_end");
switch (m_scan_value) {
case 2: // Error
break;
case 1: // Table scan
if (m_part_spec.start_part != NO_CURRENT_PART_ID)
{
late_extra_no_cache(m_part_spec.start_part);
m_file[m_part_spec.start_part]->ha_rnd_end();
}
break;
case 0:
file= m_file;
do
{
(*file)->ha_rnd_end();
} while (*(++file));
break;
}
m_part_spec.start_part= NO_CURRENT_PART_ID;
m_scan_value= 2;
DBUG_RETURN(0);
}
/*
read next row during full table scan (scan in random row order)
SYNOPSIS
rnd_next()
buf buffer that should be filled with data
This is called for each row of the table scan. When you run out of records
you should return HA_ERR_END_OF_FILE.
The Field structure for the table is the key to getting data into buf
in a manner that will allow the server to understand it.
Called from filesort.cc, records.cc, sql_handler.cc, sql_select.cc,
sql_table.cc, and sql_update.cc.
*/
int ha_partition::rnd_next(byte *buf)
{
DBUG_ASSERT(m_scan_value);
uint part_id= m_part_spec.start_part; // Cache of this variable
handler *file= m_file[part_id];
int result= HA_ERR_END_OF_FILE;
DBUG_ENTER("ha_partition::rnd_next");
DBUG_ASSERT(m_scan_value == 1);
if (part_id > m_part_spec.end_part)
{
/*
The original set of partitions to scan was empty and thus we report
the result here.
*/
goto end;
}
while (TRUE)
{
if ((result= file->rnd_next(buf)))
{
if (result == HA_ERR_RECORD_DELETED)
continue; // Probably MyISAM
if (result != HA_ERR_END_OF_FILE)
break; // Return error
/* End current partition */
late_extra_no_cache(part_id);
DBUG_PRINT("info", ("rnd_end on partition %d", part_id));
if ((result= file->ha_rnd_end()))
break;
/* Shift to next partition */
if (++part_id > m_part_spec.end_part)
{
result= HA_ERR_END_OF_FILE;
break;
}
file= m_file[part_id];
DBUG_PRINT("info", ("rnd_init on partition %d", part_id));
if ((result= file->ha_rnd_init(1)))
break;
late_extra_cache(part_id);
}
else
{
m_part_spec.start_part= part_id;
m_last_part= part_id;
table->status= 0;
DBUG_RETURN(0);
}
}
end:
m_part_spec.start_part= NO_CURRENT_PART_ID;
table->status= STATUS_NOT_FOUND;
DBUG_RETURN(result);
}
inline void store_part_id_in_pos(byte *pos, uint part_id)
{
int2store(pos, part_id);
}
inline uint get_part_id_from_pos(const byte *pos)
{
return uint2korr(pos);
}
/*
position() is called after each call to rnd_next() if the data needs
to be ordered. You can do something like the following to store
the position:
ha_store_ptr(ref, ref_length, current_position);
The server uses ref to store data. ref_length in the above case is
the size needed to store current_position. ref is just a byte array
that the server will maintain. If you are using offsets to mark rows, then
current_position should be the offset. If it is a primary key like in
BDB, then it needs to be a primary key.
Called from filesort.cc, sql_select.cc, sql_delete.cc and sql_update.cc.
*/
void ha_partition::position(const byte *record)
{
handler *file= m_file[m_last_part];
DBUG_ENTER("ha_partition::position");
file->position(record);
store_part_id_in_pos(ref, m_last_part);
memcpy((ref + PARTITION_BYTES_IN_POS), file->ref,
(ref_length - PARTITION_BYTES_IN_POS));
#ifdef SUPPORTING_PARTITION_OVER_DIFFERENT_ENGINES
#ifdef HAVE_purify
bzero(ref + PARTITION_BYTES_IN_POS + ref_length, max_ref_length-ref_length);
#endif /* HAVE_purify */
#endif
DBUG_VOID_RETURN;
}
/*
This is like rnd_next, but you are given a position to use
to determine the row. The position will be of the type that you stored in
ref. You can use ha_get_ptr(pos,ref_length) to retrieve whatever key
or position you saved when position() was called.
Called from filesort.cc records.cc sql_insert.cc sql_select.cc
sql_update.cc.
*/
int ha_partition::rnd_pos(byte * buf, byte *pos)
{
uint part_id;
handler *file;
DBUG_ENTER("ha_partition::rnd_pos");
part_id= get_part_id_from_pos((const byte *) pos);
DBUG_ASSERT(part_id < m_tot_parts);
file= m_file[part_id];
m_last_part= part_id;
DBUG_RETURN(file->rnd_pos(buf, (pos + PARTITION_BYTES_IN_POS)));
}
/****************************************************************************
MODULE index scan
****************************************************************************/
/*
Positions an index cursor to the index specified in the handle. Fetches the
row if available. If the key value is null, begin at the first key of the
index.
There are loads of optimisations possible here for the partition handler.
The same optimisations can also be checked for full table scan although
only through conditions and not from index ranges.
Phase one optimisations:
Check if the fields of the partition function are bound. If so only use
the single partition it becomes bound to.
Phase two optimisations:
If it can be deducted through range or list partitioning that only a
subset of the partitions are used, then only use those partitions.
*/
/*
index_init is always called before starting index scans (except when
starting through index_read_idx and using read_range variants).
*/
int ha_partition::index_init(uint inx, bool sorted)
{
int error= 0;
handler **file;
DBUG_ENTER("ha_partition::index_init");
active_index= inx;
m_part_spec.start_part= NO_CURRENT_PART_ID;
m_start_key.length= 0;
m_ordered= sorted;
m_curr_key_info= table->key_info+inx;
include_partition_fields_in_used_fields();
file= m_file;
do
{
/* TODO RONM: Change to index_init() when code is stable */
if ((error= (*file)->ha_index_init(inx, sorted)))
{
DBUG_ASSERT(0); // Should never happen
break;
}
} while (*(++file));
DBUG_RETURN(error);
}
/*
index_end is called at the end of an index scan to clean up any
things needed to clean up.
*/
int ha_partition::index_end()
{
int error= 0;
handler **file;
DBUG_ENTER("ha_partition::index_end");
active_index= MAX_KEY;
m_part_spec.start_part= NO_CURRENT_PART_ID;
file= m_file;
do
{
int tmp;
/* We want to execute index_end() on all handlers */
/* TODO RONM: Change to index_end() when code is stable */
if ((tmp= (*file)->ha_index_end()))
error= tmp;
} while (*(++file));
DBUG_RETURN(error);
}
/*
index_read starts a new index scan using a start key. The MySQL Server
will check the end key on its own. Thus to function properly the
partitioned handler need to ensure that it delivers records in the sort
order of the MySQL Server.
index_read can be restarted without calling index_end on the previous
index scan and without calling index_init. In this case the index_read
is on the same index as the previous index_scan. This is particularly
used in conjuntion with multi read ranges.
*/
int ha_partition::index_read(byte * buf, const byte * key,
uint key_len, enum ha_rkey_function find_flag)
{
DBUG_ENTER("ha_partition::index_read");
end_range= 0;
DBUG_RETURN(common_index_read(buf, key, key_len, find_flag));
}
int ha_partition::common_index_read(byte *buf, const byte *key, uint key_len,
enum ha_rkey_function find_flag)
{
int error;
DBUG_ENTER("ha_partition::common_index_read");
memcpy((void*)m_start_key.key, key, key_len);
m_start_key.length= key_len;
m_start_key.flag= find_flag;
m_index_scan_type= partition_index_read;
if ((error= partition_scan_set_up(buf, TRUE)))
{
DBUG_RETURN(error);
}
if (!m_ordered_scan_ongoing ||
(find_flag == HA_READ_KEY_EXACT &&
(key_len >= m_curr_key_info->key_length ||
key_len == 0)))
{
/*
We use unordered index scan either when read_range is used and flag
is set to not use ordered or when an exact key is used and in this
case all records will be sorted equal and thus the sort order of the
resulting records doesn't matter.
We also use an unordered index scan when the number of partitions to
scan is only one.
The unordered index scan will use the partition set created.
Need to set unordered scan ongoing since we can come here even when
it isn't set.
*/
m_ordered_scan_ongoing= FALSE;
error= handle_unordered_scan_next_partition(buf);
}
else
{
/*
In all other cases we will use the ordered index scan. This will use
the partition set created by the get_partition_set method.
*/
error= handle_ordered_index_scan(buf);
}
DBUG_RETURN(error);
}
/*
index_first() asks for the first key in the index.
This is similar to index_read except that there is no start key since
the scan starts from the leftmost entry and proceeds forward with
index_next.
Called from opt_range.cc, opt_sum.cc, sql_handler.cc,
and sql_select.cc.
*/
int ha_partition::index_first(byte * buf)
{
DBUG_ENTER("ha_partition::index_first");
end_range= 0;
m_index_scan_type= partition_index_first;
DBUG_RETURN(common_first_last(buf));
}
/*
index_last() asks for the last key in the index.
This is similar to index_read except that there is no start key since
the scan starts from the rightmost entry and proceeds forward with
index_prev.
Called from opt_range.cc, opt_sum.cc, sql_handler.cc,
and sql_select.cc.
*/
int ha_partition::index_last(byte * buf)
{
DBUG_ENTER("ha_partition::index_last");
m_index_scan_type= partition_index_last;
DBUG_RETURN(common_first_last(buf));
}
int ha_partition::common_first_last(byte *buf)
{
int error;
if ((error= partition_scan_set_up(buf, FALSE)))
return error;
if (!m_ordered_scan_ongoing)
return handle_unordered_scan_next_partition(buf);
return handle_ordered_index_scan(buf);
}
/*
Positions an index cursor to the index specified in key. Fetches the
row if any. This is only used to read whole keys.
TODO: Optimise this code to avoid index_init and index_end
*/
int ha_partition::index_read_idx(byte * buf, uint index, const byte * key,
uint key_len,
enum ha_rkey_function find_flag)
{
int res;
DBUG_ENTER("ha_partition::index_read_idx");
index_init(index, 0);
res= index_read(buf, key, key_len, find_flag);
index_end();
DBUG_RETURN(res);
}
/*
This is used in join_read_last_key to optimise away an ORDER BY.
Can only be used on indexes supporting HA_READ_ORDER
*/
int ha_partition::index_read_last(byte *buf, const byte *key, uint keylen)
{
DBUG_ENTER("ha_partition::index_read_last");
m_ordered= TRUE; // Safety measure
DBUG_RETURN(index_read(buf, key, keylen, HA_READ_PREFIX_LAST));
}
/*
Used to read forward through the index.
*/
int ha_partition::index_next(byte * buf)
{
DBUG_ENTER("ha_partition::index_next");
/*
TODO(low priority):
If we want partition to work with the HANDLER commands, we
must be able to do index_last() -> index_prev() -> index_next()
*/
DBUG_ASSERT(m_index_scan_type != partition_index_last);
if (!m_ordered_scan_ongoing)
{
DBUG_RETURN(handle_unordered_next(buf, FALSE));
}
DBUG_RETURN(handle_ordered_next(buf, FALSE));
}
/*
This routine is used to read the next but only if the key is the same
as supplied in the call.
*/
int ha_partition::index_next_same(byte *buf, const byte *key, uint keylen)
{
DBUG_ENTER("ha_partition::index_next_same");
DBUG_ASSERT(keylen == m_start_key.length);
DBUG_ASSERT(m_index_scan_type != partition_index_last);
if (!m_ordered_scan_ongoing)
DBUG_RETURN(handle_unordered_next(buf, TRUE));
DBUG_RETURN(handle_ordered_next(buf, TRUE));
}
/*
Used to read backwards through the index.
*/
int ha_partition::index_prev(byte * buf)
{
DBUG_ENTER("ha_partition::index_prev");
/* TODO: read comment in index_next */
DBUG_ASSERT(m_index_scan_type != partition_index_first);
DBUG_RETURN(handle_ordered_prev(buf));
}
/*
We reimplement read_range_first since we don't want the compare_key
check at the end. This is already performed in the partition handler.
read_range_next is very much different due to that we need to scan
all underlying handlers.
*/
int ha_partition::read_range_first(const key_range *start_key,
const key_range *end_key,
bool eq_range_arg, bool sorted)
{
int error;
DBUG_ENTER("ha_partition::read_range_first");
m_ordered= sorted;
eq_range= eq_range_arg;
end_range= 0;
if (end_key)
{
end_range= &save_end_range;
save_end_range= *end_key;
key_compare_result_on_equal=
((end_key->flag == HA_READ_BEFORE_KEY) ? 1 :
(end_key->flag == HA_READ_AFTER_KEY) ? -1 : 0);
}
range_key_part= m_curr_key_info->key_part;
if (!start_key) // Read first record
{
m_index_scan_type= partition_index_first;
error= common_first_last(m_rec0);
}
else
{
error= common_index_read(m_rec0,
start_key->key,
start_key->length, start_key->flag);
}
DBUG_RETURN(error);
}
int ha_partition::read_range_next()
{
DBUG_ENTER("ha_partition::read_range_next");
if (m_ordered)
{
DBUG_RETURN(handler::read_range_next());
}
DBUG_RETURN(handle_unordered_next(m_rec0, eq_range));
}
int ha_partition::partition_scan_set_up(byte * buf, bool idx_read_flag)
{
DBUG_ENTER("ha_partition::partition_scan_set_up");
if (idx_read_flag)
get_partition_set(table,buf,active_index,&m_start_key,&m_part_spec);
else
get_partition_set(table, buf, MAX_KEY, 0, &m_part_spec);
if (m_part_spec.start_part > m_part_spec.end_part)
{
/*
We discovered a partition set but the set was empty so we report
key not found.
*/
DBUG_PRINT("info", ("scan with no partition to scan"));
DBUG_RETURN(HA_ERR_END_OF_FILE);
}
if (m_part_spec.start_part == m_part_spec.end_part)
{
/*
We discovered a single partition to scan, this never needs to be
performed using the ordered index scan.
*/
DBUG_PRINT("info", ("index scan using the single partition %d",
m_part_spec.start_part));
m_ordered_scan_ongoing= FALSE;
}
else
{
/*
Set m_ordered_scan_ongoing according how the scan should be done
*/
m_ordered_scan_ongoing= m_ordered;
}
DBUG_ASSERT(m_part_spec.start_part < m_tot_parts &&
m_part_spec.end_part < m_tot_parts);
DBUG_RETURN(0);
}
/****************************************************************************
Unordered Index Scan Routines
****************************************************************************/
/*
These routines are used to scan partitions without considering order.
This is performed in two situations.
1) In read_multi_range this is the normal case
2) When performing any type of index_read, index_first, index_last where
all fields in the partition function is bound. In this case the index
scan is performed on only one partition and thus it isn't necessary to
perform any sort.
*/
int ha_partition::handle_unordered_next(byte *buf, bool next_same)
{
handler *file= file= m_file[m_part_spec.start_part];
int error;
DBUG_ENTER("ha_partition::handle_unordered_next");
/*
We should consider if this should be split into two functions as
next_same is alwas a local constant
*/
if (next_same)
{
if (!(error= file->index_next_same(buf, m_start_key.key,
m_start_key.length)))
{
m_last_part= m_part_spec.start_part;
DBUG_RETURN(0);
}
}
else if (!(error= file->index_next(buf)))
{
if (compare_key(end_range) <= 0)
{
m_last_part= m_part_spec.start_part;
DBUG_RETURN(0); // Row was in range
}
error= HA_ERR_END_OF_FILE;
}
if (error == HA_ERR_END_OF_FILE)
{
m_part_spec.start_part++; // Start using next part
error= handle_unordered_scan_next_partition(buf);
}
DBUG_RETURN(error);
}
/*
This routine is used to start the index scan on the next partition.
Both initial start and after completing scan on one partition.
*/
int ha_partition::handle_unordered_scan_next_partition(byte * buf)
{
uint i;
DBUG_ENTER("ha_partition::handle_unordered_scan_next_partition");
for (i= m_part_spec.start_part; i <= m_part_spec.end_part; i++)
{
int error;
handler *file= m_file[i];
m_part_spec.start_part= i;
switch (m_index_scan_type) {
case partition_index_read:
DBUG_PRINT("info", ("index_read on partition %d", i));
error= file->index_read(buf, m_start_key.key,
m_start_key.length,
m_start_key.flag);
break;
case partition_index_first:
DBUG_PRINT("info", ("index_first on partition %d", i));
error= file->index_first(buf);
break;
default:
DBUG_ASSERT(FALSE);
DBUG_RETURN(1);
}
if (!error)
{
if (compare_key(end_range) <= 0)
{
m_last_part= i;
DBUG_RETURN(0);
}
error= HA_ERR_END_OF_FILE;
}
if ((error != HA_ERR_END_OF_FILE) && (error != HA_ERR_KEY_NOT_FOUND))
DBUG_RETURN(error);
DBUG_PRINT("info", ("HA_ERR_END_OF_FILE on partition %d", i));
}
m_part_spec.start_part= NO_CURRENT_PART_ID;
DBUG_RETURN(HA_ERR_END_OF_FILE);
}
/*
This part contains the logic to handle index scans that require ordered
output. This includes all except those started by read_range_first with
the flag ordered set to FALSE. Thus most direct index_read and all
index_first and index_last.
We implement ordering by keeping one record plus a key buffer for each
partition. Every time a new entry is requested we will fetch a new
entry from the partition that is currently not filled with an entry.
Then the entry is put into its proper sort position.
Returning a record is done by getting the top record, copying the
record to the request buffer and setting the partition as empty on
entries.
*/
int ha_partition::handle_ordered_index_scan(byte *buf)
{
uint i, j= 0;
bool found= FALSE;
bool reverse_order= FALSE;
DBUG_ENTER("ha_partition::handle_ordered_index_scan");
m_top_entry= NO_CURRENT_PART_ID;
queue_remove_all(&queue);
for (i= m_part_spec.start_part; i <= m_part_spec.end_part; i++)
{
int error;
byte *rec_buf_ptr= rec_buf(i);
handler *file= m_file[i];
switch (m_index_scan_type) {
case partition_index_read:
error= file->index_read(rec_buf_ptr,
m_start_key.key,
m_start_key.length,
m_start_key.flag);
reverse_order= FALSE;
break;
case partition_index_first:
error= file->index_first(rec_buf_ptr);
reverse_order= FALSE;
break;
case partition_index_last:
error= file->index_last(rec_buf_ptr);
reverse_order= TRUE;
break;
default:
DBUG_ASSERT(FALSE);
DBUG_RETURN(HA_ERR_END_OF_FILE);
}
if (!error)
{
found= TRUE;
/*
Initialise queue without order first, simply insert
*/
queue_element(&queue, j++)= (byte*)queue_buf(i);
}
else if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
{
DBUG_RETURN(error);
}
}
if (found)
{
/*
We found at least one partition with data, now sort all entries and
after that read the first entry and copy it to the buffer to return in.
*/
queue_set_max_at_top(&queue, reverse_order);
queue_set_cmp_arg(&queue, (void*)m_curr_key_info);
queue.elements= j;
queue_fix(&queue);
return_top_record(buf);
DBUG_PRINT("info", ("Record returned from partition %d", m_top_entry));
DBUG_RETURN(0);
}
DBUG_RETURN(HA_ERR_END_OF_FILE);
}
void ha_partition::return_top_record(byte *buf)
{
uint part_id;
byte *key_buffer= queue_top(&queue);
byte *rec_buffer= key_buffer + PARTITION_BYTES_IN_POS;
part_id= uint2korr(key_buffer);
memcpy(buf, rec_buffer, m_rec_length);
m_last_part= part_id;
m_top_entry= part_id;
}
int ha_partition::handle_ordered_next(byte *buf, bool next_same)
{
int error;
uint part_id= m_top_entry;
handler *file= m_file[part_id];
DBUG_ENTER("ha_partition::handle_ordered_next");
if (!next_same)
error= file->index_next(rec_buf(part_id));
else
error= file->index_next_same(rec_buf(part_id), m_start_key.key,
m_start_key.length);
if (error)
{
if (error == HA_ERR_END_OF_FILE)
{
/* Return next buffered row */
queue_remove(&queue, (uint) 0);
if (queue.elements)
{
DBUG_PRINT("info", ("Record returned from partition %u (2)",
m_top_entry));
return_top_record(buf);
error= 0;
}
}
DBUG_RETURN(error);
}
queue_replaced(&queue);
return_top_record(buf);
DBUG_PRINT("info", ("Record returned from partition %u", m_top_entry));
DBUG_RETURN(0);
}
int ha_partition::handle_ordered_prev(byte *buf)
{
int error;
uint part_id= m_top_entry;
handler *file= m_file[part_id];
DBUG_ENTER("ha_partition::handle_ordered_prev");
if ((error= file->index_prev(rec_buf(part_id))))
{
if (error == HA_ERR_END_OF_FILE)
{
queue_remove(&queue, (uint) 0);
if (queue.elements)
{
return_top_record(buf);
DBUG_PRINT("info", ("Record returned from partition %d (2)",
m_top_entry));
error= 0;
}
}
DBUG_RETURN(error);
}
queue_replaced(&queue);
return_top_record(buf);
DBUG_PRINT("info", ("Record returned from partition %d", m_top_entry));
DBUG_RETURN(0);
}
void ha_partition::include_partition_fields_in_used_fields()
{
DBUG_ENTER("ha_partition::include_partition_fields_in_used_fields");
Field **ptr= m_part_field_array;
do
{
ha_set_bit_in_read_set((*ptr)->fieldnr);
} while (*(++ptr));
DBUG_VOID_RETURN;
}
/****************************************************************************
MODULE information calls
****************************************************************************/
/*
These are all first approximations of the extra, info, scan_time
and read_time calls
*/
/*
::info() is used to return information to the optimizer.
Currently this table handler doesn't implement most of the fields
really needed. SHOW also makes use of this data
Another note, if your handler doesn't proved exact record count,
you will probably want to have the following in your code:
if (records < 2)
records = 2;
The reason is that the server will optimize for cases of only a single
record. If in a table scan you don't know the number of records
it will probably be better to set records to two so you can return
as many records as you need.
Along with records a few more variables you may wish to set are:
records
deleted
data_file_length
index_file_length
delete_length
check_time
Take a look at the public variables in handler.h for more information.
Called in:
filesort.cc
ha_heap.cc
item_sum.cc
opt_sum.cc
sql_delete.cc
sql_delete.cc
sql_derived.cc
sql_select.cc
sql_select.cc
sql_select.cc
sql_select.cc
sql_select.cc
sql_show.cc
sql_show.cc
sql_show.cc
sql_show.cc
sql_table.cc
sql_union.cc
sql_update.cc
Some flags that are not implemented
HA_STATUS_POS:
This parameter is never used from the MySQL Server. It is checked in a
place in MyISAM so could potentially be used by MyISAM specific programs.
HA_STATUS_NO_LOCK:
This is declared and often used. It's only used by MyISAM.
It means that MySQL doesn't need the absolute latest statistics
information. This may save the handler from doing internal locks while
retrieving statistics data.
*/
void ha_partition::info(uint flag)
{
handler *file, **file_array;
DBUG_ENTER("ha_partition:info");
if (flag & HA_STATUS_AUTO)
{
DBUG_PRINT("info", ("HA_STATUS_AUTO"));
/*
The auto increment value is only maintained by the first handler
so we will only call this.
*/
m_file[0]->info(HA_STATUS_AUTO);
}
if (flag & HA_STATUS_VARIABLE)
{
DBUG_PRINT("info", ("HA_STATUS_VARIABLE"));
/*
Calculates statistical variables
records: Estimate of number records in table
We report sum (always at least 2)
deleted: Estimate of number holes in the table due to
deletes
We report sum
data_file_length: Length of data file, in principle bytes in table
We report sum
index_file_length: Length of index file, in principle bytes in
indexes in the table
We report sum
mean_record_length:Mean record length in the table
We calculate this
check_time: Time of last check (only applicable to MyISAM)
We report last time of all underlying handlers
*/
records= 0;
deleted= 0;
data_file_length= 0;
index_file_length= 0;
check_time= 0;
file_array= m_file;
do
{
file= *file_array;
file->info(HA_STATUS_VARIABLE);
records+= file->records;
deleted+= file->deleted;
data_file_length+= file->data_file_length;
index_file_length+= file->index_file_length;
if (file->check_time > check_time)
check_time= file->check_time;
} while (*(++file_array));
if (records < 2 &&
m_table_flags & HA_NOT_EXACT_COUNT)
records= 2;
if (records > 0)
mean_rec_length= (ulong) (data_file_length / records);
else
mean_rec_length= 1; //? What should we set here
}
if (flag & HA_STATUS_CONST)
{
DBUG_PRINT("info", ("HA_STATUS_CONST"));
/*
Recalculate loads of constant variables. MyISAM also sets things
directly on the table share object.
Check whether this should be fixed since handlers should not
change things directly on the table object.
Monty comment: This should NOT be changed! It's the handlers
responsibility to correct table->s->keys_xxxx information if keys
have been disabled.
The most important parameters set here is records per key on
all indexes. block_size and primar key ref_length.
For each index there is an array of rec_per_key.
As an example if we have an index with three attributes a,b and c
we will have an array of 3 rec_per_key.
rec_per_key[0] is an estimate of number of records divided by
number of unique values of the field a.
rec_per_key[1] is an estimate of the number of records divided
by the number of unique combinations of the fields a and b.
rec_per_key[2] is an estimate of the number of records divided
by the number of unique combinations of the fields a,b and c.
Many handlers only set the value of rec_per_key when all fields
are bound (rec_per_key[2] in the example above).
If the handler doesn't support statistics, it should set all of the
above to 0.
We will allow the first handler to set the rec_per_key and use
this as an estimate on the total table.
max_data_file_length: Maximum data file length
We ignore it, is only used in
SHOW TABLE STATUS
max_index_file_length: Maximum index file length
We ignore it since it is never used
block_size: Block size used
We set it to the value of the first handler
sortkey: Never used at any place so ignored
ref_length: We set this to the value calculated
and stored in local object
raid_type: Set by first handler (MyISAM)
raid_chunks: Set by first handler (MyISAM)
raid_chunksize: Set by first handler (MyISAM)
create_time: Creation time of table
Set by first handler
So we calculate these constants by using the variables on the first
handler.
*/
file= m_file[0];
file->info(HA_STATUS_CONST);
create_time= file->create_time;
raid_type= file->raid_type;
raid_chunks= file->raid_chunks;
raid_chunksize= file->raid_chunksize;
ref_length= m_ref_length;
}
if (flag & HA_STATUS_ERRKEY)
{
handler *file= m_file[m_last_part];
DBUG_PRINT("info", ("info: HA_STATUS_ERRKEY"));
/*
This flag is used to get index number of the unique index that
reported duplicate key
We will report the errkey on the last handler used and ignore the rest
*/
file->info(HA_STATUS_ERRKEY);
if (file->errkey != (uint) -1)
errkey= file->errkey;
}
if (flag & HA_STATUS_TIME)
{
DBUG_PRINT("info", ("info: HA_STATUS_TIME"));
/*
This flag is used to set the latest update time of the table.
Used by SHOW commands
We will report the maximum of these times
*/
update_time= 0;
file_array= m_file;
do
{
file= *file_array;
file->info(HA_STATUS_TIME);
if (file->update_time > update_time)
update_time= file->update_time;
} while (*(++file_array));
}
DBUG_VOID_RETURN;
}
/*
extra() is called whenever the server wishes to send a hint to
the storage engine. The MyISAM engine implements the most hints.
We divide the parameters into the following categories:
1) Parameters used by most handlers
2) Parameters used by some non-MyISAM handlers
3) Parameters used only by MyISAM
4) Parameters only used by temporary tables for query processing
5) Parameters only used by MyISAM internally
6) Parameters not used at all
The partition handler need to handle category 1), 2) and 3).
1) Parameters used by most handlers
-----------------------------------
HA_EXTRA_RESET:
This option is used by most handlers and it resets the handler state
to the same state as after an open call. This includes releasing
any READ CACHE or WRITE CACHE or other internal buffer used.
It is called from the reset method in the handler interface. There are
three instances where this is called.
1) After completing a INSERT ... SELECT ... query the handler for the
table inserted into is reset
2) It is called from close_thread_table which in turn is called from
close_thread_tables except in the case where the tables are locked
in which case ha_commit_stmt is called instead.
It is only called from here if flush_version hasn't changed and the
table is not an old table when calling close_thread_table.
close_thread_tables is called from many places as a general clean up
function after completing a query.
3) It is called when deleting the QUICK_RANGE_SELECT object if the
QUICK_RANGE_SELECT object had its own handler object. It is called
immediatley before close of this local handler object.
HA_EXTRA_KEYREAD:
HA_EXTRA_NO_KEYREAD:
These parameters are used to provide an optimisation hint to the handler.
If HA_EXTRA_KEYREAD is set it is enough to read the index fields, for
many handlers this means that the index-only scans can be used and it
is not necessary to use the real records to satisfy this part of the
query. Index-only scans is a very important optimisation for disk-based
indexes. For main-memory indexes most indexes contain a reference to the
record and thus KEYREAD only says that it is enough to read key fields.
HA_EXTRA_NO_KEYREAD disables this for the handler, also HA_EXTRA_RESET
will disable this option.
The handler will set HA_KEYREAD_ONLY in its table flags to indicate this
feature is supported.
HA_EXTRA_FLUSH:
Indication to flush tables to disk, called at close_thread_table to
ensure disk based tables are flushed at end of query execution.
2) Parameters used by some non-MyISAM handlers
----------------------------------------------
HA_EXTRA_RETRIEVE_ALL_COLS:
Many handlers have implemented optimisations to avoid fetching all
fields when retrieving data. In certain situations all fields need
to be retrieved even though the query_id is not set on all field
objects.
It is called from copy_data_between_tables where all fields are
copied without setting query_id before calling the handlers.
It is called from UPDATE statements when the fields of the index
used is updated or ORDER BY is used with UPDATE.
And finally when calculating checksum of a table using the CHECKSUM
command.
HA_EXTRA_RETRIEVE_PRIMARY_KEY:
In some situations it is mandatory to retrieve primary key fields
independent of the query id's. This extra flag specifies that fetch
of primary key fields is mandatory.
HA_EXTRA_KEYREAD_PRESERVE_FIELDS:
This is a strictly InnoDB feature that is more or less undocumented.
When it is activated InnoDB copies field by field from its fetch
cache instead of all fields in one memcpy. Have no idea what the
purpose of this is.
Cut from include/my_base.h:
When using HA_EXTRA_KEYREAD, overwrite only key member fields and keep
other fields intact. When this is off (by default) InnoDB will use memcpy
to overwrite entire row.
HA_EXTRA_IGNORE_DUP_KEY:
HA_EXTRA_NO_IGNORE_DUP_KEY:
Informs the handler to we will not stop the transaction if we get an
duplicate key errors during insert/upate.
Always called in pair, triggered by INSERT IGNORE and other similar
SQL constructs.
Not used by MyISAM.
3) Parameters used only by MyISAM
---------------------------------
HA_EXTRA_NORMAL:
Only used in MyISAM to reset quick mode, not implemented by any other
handler. Quick mode is also reset in MyISAM by HA_EXTRA_RESET.
It is called after completing a successful DELETE query if the QUICK
option is set.
HA_EXTRA_QUICK:
When the user does DELETE QUICK FROM table where-clause; this extra
option is called before the delete query is performed and
HA_EXTRA_NORMAL is called after the delete query is completed.
Temporary tables used internally in MySQL always set this option
The meaning of quick mode is that when deleting in a B-tree no merging
of leafs is performed. This is a common method and many large DBMS's
actually only support this quick mode since it is very difficult to
merge leaves in a tree used by many threads concurrently.
HA_EXTRA_CACHE:
This flag is usually set with extra_opt along with a cache size.
The size of this buffer is set by the user variable
record_buffer_size. The value of this cache size is the amount of
data read from disk in each fetch when performing a table scan.
This means that before scanning a table it is normal to call
extra with HA_EXTRA_CACHE and when the scan is completed to call
HA_EXTRA_NO_CACHE to release the cache memory.
Some special care is taken when using this extra parameter since there
could be a write ongoing on the table in the same statement. In this
one has to take special care since there might be a WRITE CACHE as
well. HA_EXTRA_CACHE specifies using a READ CACHE and using
READ CACHE and WRITE CACHE at the same time is not possible.
Only MyISAM currently use this option.
It is set when doing full table scans using rr_sequential and
reset when completing such a scan with end_read_record
(resetting means calling extra with HA_EXTRA_NO_CACHE).
It is set in filesort.cc for MyISAM internal tables and it is set in
a multi-update where HA_EXTRA_CACHE is called on a temporary result
table and after that ha_rnd_init(0) on table to be updated
and immediately after that HA_EXTRA_NO_CACHE on table to be updated.
Apart from that it is always used from init_read_record but not when
used from UPDATE statements. It is not used from DELETE statements
with ORDER BY and LIMIT but it is used in normal scan loop in DELETE
statements. The reason here is that DELETE's in MyISAM doesn't move
existings data rows.
It is also set in copy_data_between_tables when scanning the old table
to copy over to the new table.
And it is set in join_init_read_record where quick objects are used
to perform a scan on the table. In this case the full table scan can
even be performed multiple times as part of the nested loop join.
For purposes of the partition handler it is obviously necessary to have
special treatment of this extra call. If we would simply pass this
extra call down to each handler we would allocate
cache size * no of partitions amount of memory and this is not
necessary since we will only scan one partition at a time when doing
full table scans.
Thus we treat it by first checking whether we have MyISAM handlers in
the table, if not we simply ignore the call and if we have we will
record the call but will not call any underlying handler yet. Then
when performing the sequential scan we will check this recorded value
and call extra_opt whenever we start scanning a new partition.
monty: Neads to be fixed so that it's passed to all handlers when we
move to another partition during table scan.
HA_EXTRA_NO_CACHE:
When performing a UNION SELECT HA_EXTRA_NO_CACHE is called from the
flush method in the select_union class.
It is used to some extent when insert delayed inserts.
See HA_EXTRA_RESET_STATE for use in conjunction with delete_all_rows().
It should be ok to call HA_EXTRA_NO_CACHE on all underlying handlers
if they are MyISAM handlers. Other handlers we can ignore the call
for. If no cache is in use they will quickly return after finding
this out. And we also ensure that all caches are disabled and no one
is left by mistake.
In the future this call will probably be deleted an we will instead call
::reset();
HA_EXTRA_WRITE_CACHE:
See above, called from various places. It is mostly used when we
do INSERT ... SELECT
No special handling to save cache space is developed currently.
HA_EXTRA_PREPARE_FOR_UPDATE:
This is called as part of a multi-table update. When the table to be
updated is also scanned then this informs MyISAM handler to drop any
caches if dynamic records are used (fixed size records do not care
about this call). We pass this along to all underlying MyISAM handlers
and ignore it for the rest.
HA_EXTRA_PREPARE_FOR_DELETE:
Only used by MyISAM, called in preparation for a DROP TABLE.
It's used mostly by Windows that cannot handle dropping an open file.
On other platforms it has the same effect as HA_EXTRA_FORCE_REOPEN.
HA_EXTRA_READCHECK:
HA_EXTRA_NO_READCHECK:
Only one call to HA_EXTRA_NO_READCHECK from ha_open where it says that
this is not needed in SQL. The reason for this call is that MyISAM sets
the READ_CHECK_USED in the open call so the call is needed for MyISAM
to reset this feature.
The idea with this parameter was to inform of doing/not doing a read
check before applying an update. Since SQL always performs a read before
applying the update No Read Check is needed in MyISAM as well.
This is a cut from Docs/myisam.txt
Sometimes you might want to force an update without checking whether
another user has changed the record since you last read it. This is
somewhat dangerous, so it should ideally not be used. That can be
accomplished by wrapping the mi_update() call in two calls to mi_extra(),
using these functions:
HA_EXTRA_NO_READCHECK=5 No readcheck on update
HA_EXTRA_READCHECK=6 Use readcheck (def)
HA_EXTRA_FORCE_REOPEN:
Only used by MyISAM, called when altering table, closing tables to
enforce a reopen of the table files.
4) Parameters only used by temporary tables for query processing
----------------------------------------------------------------
HA_EXTRA_RESET_STATE:
Same as HA_EXTRA_RESET except that buffers are not released. If there is
a READ CACHE it is reinit'ed. A cache is reinit'ed to restart reading
or to change type of cache between READ CACHE and WRITE CACHE.
This extra function is always called immediately before calling
delete_all_rows on the handler for temporary tables.
There are cases however when HA_EXTRA_RESET_STATE isn't called in
a similar case for a temporary table in sql_union.cc and in two other
cases HA_EXTRA_NO_CACHE is called before and HA_EXTRA_WRITE_CACHE
called afterwards.
The case with HA_EXTRA_NO_CACHE and HA_EXTRA_WRITE_CACHE means
disable caching, delete all rows and enable WRITE CACHE. This is
used for temporary tables containing distinct sums and a
functional group.
The only case that delete_all_rows is called on non-temporary tables
is in sql_delete.cc when DELETE FROM table; is called by a user.
In this case no special extra calls are performed before or after this
call.
The partition handler should not need to bother about this one. It
should never be called.
HA_EXTRA_NO_ROWS:
Don't insert rows indication to HEAP and MyISAM, only used by temporary
tables used in query processing.
Not handled by partition handler.
5) Parameters only used by MyISAM internally
--------------------------------------------
HA_EXTRA_REINIT_CACHE:
This call reinitialises the READ CACHE described above if there is one
and otherwise the call is ignored.
We can thus safely call it on all underlying handlers if they are
MyISAM handlers. It is however never called so we don't handle it at all.
HA_EXTRA_FLUSH_CACHE:
Flush WRITE CACHE in MyISAM. It is only from one place in the code.
This is in sql_insert.cc where it is called if the table_flags doesn't
contain HA_DUPP_POS. The only handler having the HA_DUPP_POS set is the
MyISAM handler and so the only handler not receiving this call is MyISAM.
Thus in effect this call is called but never used. Could be removed
from sql_insert.cc
HA_EXTRA_NO_USER_CHANGE:
Only used by MyISAM, never called.
Simulates lock_type as locked.
HA_EXTRA_WAIT_LOCK:
HA_EXTRA_WAIT_NOLOCK:
Only used by MyISAM, called from MyISAM handler but never from server
code on top of the handler.
Sets lock_wait on/off
HA_EXTRA_NO_KEYS:
Only used MyISAM, only used internally in MyISAM handler, never called
from server level.
HA_EXTRA_KEYREAD_CHANGE_POS:
HA_EXTRA_REMEMBER_POS:
HA_EXTRA_RESTORE_POS:
HA_EXTRA_PRELOAD_BUFFER_SIZE:
HA_EXTRA_CHANGE_KEY_TO_DUP:
HA_EXTRA_CHANGE_KEY_TO_UNIQUE:
Only used by MyISAM, never called.
6) Parameters not used at all
-----------------------------
HA_EXTRA_KEY_CACHE:
HA_EXTRA_NO_KEY_CACHE:
This parameters are no longer used and could be removed.
*/
int ha_partition::extra(enum ha_extra_function operation)
{
DBUG_ENTER("ha_partition:extra");
DBUG_PRINT("info", ("operation: %d", (int) operation));
switch (operation) {
/* Category 1), used by most handlers */
case HA_EXTRA_KEYREAD:
case HA_EXTRA_NO_KEYREAD:
case HA_EXTRA_FLUSH:
DBUG_RETURN(loop_extra(operation));
/* Category 2), used by non-MyISAM handlers */
case HA_EXTRA_IGNORE_DUP_KEY:
case HA_EXTRA_NO_IGNORE_DUP_KEY:
case HA_EXTRA_RETRIEVE_ALL_COLS:
case HA_EXTRA_RETRIEVE_PRIMARY_KEY:
case HA_EXTRA_KEYREAD_PRESERVE_FIELDS:
{
if (!m_myisam)
DBUG_RETURN(loop_extra(operation));
break;
}
/* Category 3), used by MyISAM handlers */
case HA_EXTRA_NORMAL:
case HA_EXTRA_QUICK:
case HA_EXTRA_NO_READCHECK:
case HA_EXTRA_PREPARE_FOR_UPDATE:
case HA_EXTRA_PREPARE_FOR_DELETE:
case HA_EXTRA_FORCE_REOPEN:
{
if (m_myisam)
DBUG_RETURN(loop_extra(operation));
break;
}
case HA_EXTRA_CACHE:
{
prepare_extra_cache(0);
break;
}
case HA_EXTRA_NO_CACHE:
{
m_extra_cache= FALSE;
m_extra_cache_size= 0;
DBUG_RETURN(loop_extra(operation));
}
default:
{
/* Temporary crash to discover what is wrong */
DBUG_ASSERT(0);
break;
}
}
DBUG_RETURN(0);
}
/*
This will in the future be called instead of extra(HA_EXTRA_RESET) as this
is such a common call
*/
int ha_partition::reset(void)
{
int result= 0, tmp;
handler **file;
DBUG_ENTER("ha_partition::reset");
file= m_file;
do
{
if ((tmp= (*file)->reset()))
result= tmp;
} while (*(++file));
DBUG_RETURN(result);
}
int ha_partition::extra_opt(enum ha_extra_function operation, ulong cachesize)
{
DBUG_ENTER("ha_partition::extra_opt()");
DBUG_ASSERT(HA_EXTRA_CACHE == operation);
prepare_extra_cache(cachesize);
DBUG_RETURN(0);
}
void ha_partition::prepare_extra_cache(uint cachesize)
{
DBUG_ENTER("ha_partition::prepare_extra_cache()");
m_extra_cache= TRUE;
m_extra_cache_size= cachesize;
if (m_part_spec.start_part != NO_CURRENT_PART_ID)
{
DBUG_ASSERT(m_part_spec.start_part == 0);
late_extra_cache(0);
}
DBUG_VOID_RETURN;
}
int ha_partition::loop_extra(enum ha_extra_function operation)
{
int result= 0, tmp;
handler **file;
DBUG_ENTER("ha_partition::loop_extra()");
for (file= m_file; *file; file++)
{
if ((tmp= (*file)->extra(operation)))
result= tmp;
}
DBUG_RETURN(result);
}
void ha_partition::late_extra_cache(uint partition_id)
{
handler *file;
DBUG_ENTER("ha_partition::late_extra_cache");
if (!m_extra_cache)
DBUG_VOID_RETURN;
file= m_file[partition_id];
if (m_extra_cache_size == 0)
VOID(file->extra(HA_EXTRA_CACHE));
else
VOID(file->extra_opt(HA_EXTRA_CACHE, m_extra_cache_size));
DBUG_VOID_RETURN;
}
void ha_partition::late_extra_no_cache(uint partition_id)
{
handler *file;
DBUG_ENTER("ha_partition::late_extra_no_cache");
if (!m_extra_cache)
DBUG_VOID_RETURN;
file= m_file[partition_id];
VOID(file->extra(HA_EXTRA_NO_CACHE));
DBUG_VOID_RETURN;
}
/****************************************************************************
MODULE optimiser support
****************************************************************************/
const key_map *ha_partition::keys_to_use_for_scanning()
{
DBUG_ENTER("ha_partition::keys_to_use_for_scanning");
DBUG_RETURN(m_file[0]->keys_to_use_for_scanning());
}
double ha_partition::scan_time()
{
double scan_time= 0;
handler **file;
DBUG_ENTER("ha_partition::scan_time");
for (file= m_file; *file; file++)
scan_time+= (*file)->scan_time();
DBUG_RETURN(scan_time);
}
/*
This will be optimised later to include whether or not the index can
be used with partitioning. To achieve we need to add another parameter
that specifies how many of the index fields that are bound in the ranges.
Possibly added as a new call to handlers.
*/
double ha_partition::read_time(uint index, uint ranges, ha_rows rows)
{
DBUG_ENTER("ha_partition::read_time");
DBUG_RETURN(m_file[0]->read_time(index, ranges, rows));
}
/*
Given a starting key, and an ending key estimate the number of rows that
will exist between the two. end_key may be empty which in case determine
if start_key matches any rows.
Called from opt_range.cc by check_quick_keys().
monty: MUST be called for each range and added.
Note that MySQL will assume that if this returns 0 there is no
matching rows for the range!
*/
ha_rows ha_partition::records_in_range(uint inx, key_range *min_key,
key_range *max_key)
{
ha_rows in_range= 0;
handler **file;
DBUG_ENTER("ha_partition::records_in_range");
file= m_file;
do
{
in_range+= (*file)->records_in_range(inx, min_key, max_key);
} while (*(++file));
DBUG_RETURN(in_range);
}
ha_rows ha_partition::estimate_rows_upper_bound()
{
ha_rows rows, tot_rows= 0;
handler **file;
DBUG_ENTER("ha_partition::estimate_rows_upper_bound");
file= m_file;
do
{
rows= (*file)->estimate_rows_upper_bound();
if (rows == HA_POS_ERROR)
DBUG_RETURN(HA_POS_ERROR);
tot_rows+= rows;
} while (*(++file));
DBUG_RETURN(tot_rows);
}
uint8 ha_partition::table_cache_type()
{
DBUG_ENTER("ha_partition::table_cache_type");
DBUG_RETURN(m_file[0]->table_cache_type());
}
/****************************************************************************
MODULE print messages
****************************************************************************/
const char *ha_partition::index_type(uint inx)
{
DBUG_ENTER("ha_partition::index_type");
DBUG_RETURN(m_file[0]->index_type(inx));
}
void ha_partition::print_error(int error, myf errflag)
{
DBUG_ENTER("ha_partition::print_error");
/* Should probably look for my own errors first */
/* monty: needs to be called for the last used partition ! */
m_file[0]->print_error(error, errflag);
DBUG_VOID_RETURN;
}
bool ha_partition::get_error_message(int error, String *buf)
{
DBUG_ENTER("ha_partition::get_error_message");
/* Should probably look for my own errors first */
/* monty: needs to be called for the last used partition ! */
DBUG_RETURN(m_file[0]->get_error_message(error, buf));
}
/****************************************************************************
MODULE handler characteristics
****************************************************************************/
/*
If frm_error() is called then we will use this to to find out what file
extensions exist for the storage engine. This is also used by the default
rename_table and delete_table method in handler.cc.
*/
static const char *ha_partition_ext[]=
{
ha_par_ext, NullS
};
const char **ha_partition::bas_ext() const
{ return ha_partition_ext; }
uint ha_partition::min_of_the_max_uint(uint (handler::*operator_func)(void) const) const
{
handler **file;
uint min_of_the_max= ((*m_file)->*operator_func)();
for (file= m_file+1; *file; file++)
{
uint tmp= ((*file)->*operator_func)();
set_if_smaller(min_of_the_max, tmp);
}
return min_of_the_max;
}
uint ha_partition::max_supported_key_parts() const
{
return min_of_the_max_uint(&handler::max_supported_key_parts);
}
uint ha_partition::max_supported_key_length() const
{
return min_of_the_max_uint(&handler::max_supported_key_length);
}
uint ha_partition::max_supported_key_part_length() const
{
return min_of_the_max_uint(&handler::max_supported_key_part_length);
}
uint ha_partition::max_supported_record_length() const
{
return min_of_the_max_uint(&handler::max_supported_record_length);
}
uint ha_partition::max_supported_keys() const
{
return min_of_the_max_uint(&handler::max_supported_keys);
}
uint ha_partition::extra_rec_buf_length() const
{
handler **file;
uint max= (*m_file)->extra_rec_buf_length();
for (file= m_file, file++; *file; file++)
if (max < (*file)->extra_rec_buf_length())
max= (*file)->extra_rec_buf_length();
return max;
}
uint ha_partition::min_record_length(uint options) const
{
handler **file;
uint max= (*m_file)->min_record_length(options);
for (file= m_file, file++; *file; file++)
if (max < (*file)->min_record_length(options))
max= (*file)->min_record_length(options);
return max;
}
/****************************************************************************
MODULE compare records
****************************************************************************/
/*
We get two references and need to check if those records are the same.
If they belong to different partitions we decide that they are not
the same record. Otherwise we use the particular handler to decide if
they are the same. Sort in partition id order if not equal.
*/
int ha_partition::cmp_ref(const byte *ref1, const byte *ref2)
{
uint part_id;
my_ptrdiff_t diff1, diff2;
handler *file;
DBUG_ENTER("ha_partition::cmp_ref");
if ((ref1[0] == ref2[0]) && (ref1[1] == ref2[1]))
{
part_id= get_part_id_from_pos(ref1);
file= m_file[part_id];
DBUG_ASSERT(part_id < m_tot_parts);
DBUG_RETURN(file->cmp_ref((ref1 + PARTITION_BYTES_IN_POS),
(ref2 + PARTITION_BYTES_IN_POS)));
}
diff1= ref2[1] - ref1[1];
diff2= ref2[0] - ref1[0];
if (diff1 > 0)
{
DBUG_RETURN(-1);
}
if (diff1 < 0)
{
DBUG_RETURN(+1);
}
if (diff2 > 0)
{
DBUG_RETURN(-1);
}
DBUG_RETURN(+1);
}
/****************************************************************************
MODULE auto increment
****************************************************************************/
void ha_partition::restore_auto_increment()
{
DBUG_ENTER("ha_partition::restore_auto_increment");
DBUG_VOID_RETURN;
}
/*
This method is called by update_auto_increment which in turn is called
by the individual handlers as part of write_row. We will always let
the first handler keep track of the auto increment value for all
partitions.
*/
ulonglong ha_partition::get_auto_increment()
{
DBUG_ENTER("ha_partition::get_auto_increment");
DBUG_RETURN(m_file[0]->get_auto_increment());
}
/****************************************************************************
MODULE initialise handler for HANDLER call
****************************************************************************/
void ha_partition::init_table_handle_for_HANDLER()
{
return;
}
/****************************************************************************
MODULE Partition Share
****************************************************************************/
/*
Service routines for ... methods.
-------------------------------------------------------------------------
Variables for partition share methods. A hash used to track open tables.
A mutex for the hash table and an init variable to check if hash table
is initialised.
There is also a constant ending of the partition handler file name.
*/
#ifdef NOT_USED
static HASH partition_open_tables;
static pthread_mutex_t partition_mutex;
static int partition_init= 0;
/*
Function we use in the creation of our hash to get key.
*/
static byte *partition_get_key(PARTITION_SHARE *share, uint *length,
my_bool not_used __attribute__ ((unused)))
{
*length= share->table_name_length;
return (byte *) share->table_name;
}
/*
Example of simple lock controls. The "share" it creates is structure we
will pass to each partition handler. Do you have to have one of these?
Well, you have pieces that are used for locking, and they are needed to
function.
*/
static PARTITION_SHARE *get_share(const char *table_name, TABLE *table)
{
PARTITION_SHARE *share;
uint length;
char *tmp_name;
/*
So why does this exist? There is no way currently to init a storage
engine.
Innodb and BDB both have modifications to the server to allow them to
do this. Since you will not want to do this, this is probably the next
best method.
*/
if (!partition_init)
{
/* Hijack a mutex for init'ing the storage engine */
pthread_mutex_lock(&LOCK_mysql_create_db);
if (!partition_init)
{
partition_init++;
VOID(pthread_mutex_init(&partition_mutex, MY_MUTEX_INIT_FAST));
(void) hash_init(&partition_open_tables, system_charset_info, 32, 0, 0,
(hash_get_key) partition_get_key, 0, 0);
}
pthread_mutex_unlock(&LOCK_mysql_create_db);
}
pthread_mutex_lock(&partition_mutex);
length= (uint) strlen(table_name);
if (!(share= (PARTITION_SHARE *) hash_search(&partition_open_tables,
(byte *) table_name, length)))
{
if (!(share= (PARTITION_SHARE *)
my_multi_malloc(MYF(MY_WME | MY_ZEROFILL),
&share, sizeof(*share),
&tmp_name, length + 1, NullS)))
{
pthread_mutex_unlock(&partition_mutex);
return NULL;
}
share->use_count= 0;
share->table_name_length= length;
share->table_name= tmp_name;
strmov(share->table_name, table_name);
if (my_hash_insert(&partition_open_tables, (byte *) share))
goto error;
thr_lock_init(&share->lock);
pthread_mutex_init(&share->mutex, MY_MUTEX_INIT_FAST);
}
share->use_count++;
pthread_mutex_unlock(&partition_mutex);
return share;
error:
pthread_mutex_unlock(&partition_mutex);
my_free((gptr) share, MYF(0));
return NULL;
}
/*
Free lock controls. We call this whenever we close a table. If the table
had the last reference to the share then we free memory associated with
it.
*/
static int free_share(PARTITION_SHARE *share)
{
pthread_mutex_lock(&partition_mutex);
if (!--share->use_count)
{
hash_delete(&partition_open_tables, (byte *) share);
thr_lock_delete(&share->lock);
pthread_mutex_destroy(&share->mutex);
my_free((gptr) share, MYF(0));
}
pthread_mutex_unlock(&partition_mutex);
return 0;
}
#endif /* NOT_USED */
Reference in a new issue View git blame Copy permalink