mariadb/storage/blackhole/ha_blackhole.cc
2019-06-14 07:36:47 +02:00

459 lines
12 KiB
C++

/* Copyright (c) 2005, 2012, 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 02110-1335 USA */
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#define MYSQL_SERVER 1
#include <my_global.h>
#include "sql_priv.h"
#include "unireg.h"
#include "ha_blackhole.h"
#include "sql_class.h" // THD, SYSTEM_THREAD_SLAVE_SQL
/**
Checks if the param 'thd' is pointing to slave applier thread and row based
replication is in use.
A row event will have its thd->query() == NULL except in cases where
replicate_annotate_row_events is enabled. In the later case the thd->query()
will be pointing to the query, received through replicated annotate event
from master.
@param thd pointer to a THD instance
@return TRUE if thread is slave applier and row based replication is in use
*/
static bool is_row_based_replication(THD *thd)
{
return thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
(thd->query() == NULL || thd->variables.binlog_annotate_row_events);
}
/* Static declarations for handlerton */
static handler *blackhole_create_handler(handlerton *hton,
TABLE_SHARE *table,
MEM_ROOT *mem_root)
{
return new (mem_root) ha_blackhole(hton, table);
}
/* Static declarations for shared structures */
static mysql_mutex_t blackhole_mutex;
static HASH blackhole_open_tables;
static st_blackhole_share *get_share(const char *table_name);
static void free_share(st_blackhole_share *share);
/*****************************************************************************
** BLACKHOLE tables
*****************************************************************************/
ha_blackhole::ha_blackhole(handlerton *hton,
TABLE_SHARE *table_arg)
:handler(hton, table_arg)
{}
int ha_blackhole::open(const char *name, int mode, uint test_if_locked)
{
DBUG_ENTER("ha_blackhole::open");
if (!(share= get_share(name)))
DBUG_RETURN(HA_ERR_OUT_OF_MEM);
thr_lock_data_init(&share->lock, &lock, NULL);
DBUG_RETURN(0);
}
int ha_blackhole::close(void)
{
DBUG_ENTER("ha_blackhole::close");
free_share(share);
DBUG_RETURN(0);
}
int ha_blackhole::create(const char *name, TABLE *table_arg,
HA_CREATE_INFO *create_info)
{
DBUG_ENTER("ha_blackhole::create");
DBUG_RETURN(0);
}
/*
Intended to support partitioning.
Allows a particular partition to be truncated.
*/
int ha_blackhole::truncate()
{
DBUG_ENTER("ha_blackhole::truncate");
DBUG_RETURN(0);
}
const char *ha_blackhole::index_type(uint key_number)
{
DBUG_ENTER("ha_blackhole::index_type");
DBUG_RETURN((table_share->key_info[key_number].flags & HA_FULLTEXT) ?
"FULLTEXT" :
(table_share->key_info[key_number].flags & HA_SPATIAL) ?
"SPATIAL" :
(table_share->key_info[key_number].algorithm ==
HA_KEY_ALG_RTREE) ? "RTREE" : "BTREE");
}
int ha_blackhole::write_row(uchar * buf)
{
DBUG_ENTER("ha_blackhole::write_row");
DBUG_RETURN(table->next_number_field ? update_auto_increment() : 0);
}
int ha_blackhole::update_row(const uchar *old_data, const uchar *new_data)
{
DBUG_ENTER("ha_blackhole::update_row");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
DBUG_RETURN(0);
DBUG_RETURN(HA_ERR_WRONG_COMMAND);
}
int ha_blackhole::delete_row(const uchar *buf)
{
DBUG_ENTER("ha_blackhole::delete_row");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
DBUG_RETURN(0);
DBUG_RETURN(HA_ERR_WRONG_COMMAND);
}
int ha_blackhole::rnd_init(bool scan)
{
DBUG_ENTER("ha_blackhole::rnd_init");
DBUG_RETURN(0);
}
int ha_blackhole::rnd_next(uchar *buf)
{
int rc;
DBUG_ENTER("ha_blackhole::rnd_next");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
rc= 0;
else
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::rnd_pos(uchar * buf, uchar *pos)
{
DBUG_ENTER("ha_blackhole::rnd_pos");
DBUG_ASSERT(0);
DBUG_RETURN(0);
}
void ha_blackhole::position(const uchar *record)
{
DBUG_ENTER("ha_blackhole::position");
DBUG_ASSERT(0);
DBUG_VOID_RETURN;
}
int ha_blackhole::info(uint flag)
{
DBUG_ENTER("ha_blackhole::info");
bzero((char*) &stats, sizeof(stats));
if (flag & HA_STATUS_AUTO)
stats.auto_increment_value= 1;
DBUG_RETURN(0);
}
int ha_blackhole::external_lock(THD *thd, int lock_type)
{
DBUG_ENTER("ha_blackhole::external_lock");
DBUG_RETURN(0);
}
THR_LOCK_DATA **ha_blackhole::store_lock(THD *thd,
THR_LOCK_DATA **to,
enum thr_lock_type lock_type)
{
DBUG_ENTER("ha_blackhole::store_lock");
if (lock_type != TL_IGNORE && lock.type == TL_UNLOCK)
{
/*
Here is where we get into the guts of a row level lock.
If TL_UNLOCK is set
If we are not doing a LOCK TABLE or DISCARD/IMPORT
TABLESPACE, then allow multiple writers
*/
if ((lock_type >= TL_WRITE_CONCURRENT_INSERT &&
lock_type <= TL_WRITE) && !thd_in_lock_tables(thd)
&& !thd_tablespace_op(thd))
lock_type = TL_WRITE_ALLOW_WRITE;
/*
In queries of type INSERT INTO t1 SELECT ... FROM t2 ...
MySQL would use the lock TL_READ_NO_INSERT on t2, and that
would conflict with TL_WRITE_ALLOW_WRITE, blocking all inserts
to t2. Convert the lock to a normal read lock to allow
concurrent inserts to t2.
*/
if (lock_type == TL_READ_NO_INSERT && !thd_in_lock_tables(thd))
lock_type = TL_READ;
lock.type= lock_type;
}
*to++= &lock;
DBUG_RETURN(to);
}
int ha_blackhole::index_read_map(uchar * buf, const uchar * key,
key_part_map keypart_map,
enum ha_rkey_function find_flag)
{
int rc;
DBUG_ENTER("ha_blackhole::index_read");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
rc= 0;
else
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_read_idx_map(uchar * buf, uint idx, const uchar * key,
key_part_map keypart_map,
enum ha_rkey_function find_flag)
{
int rc;
DBUG_ENTER("ha_blackhole::index_read_idx");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
rc= 0;
else
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_read_last_map(uchar * buf, const uchar * key,
key_part_map keypart_map)
{
int rc;
DBUG_ENTER("ha_blackhole::index_read_last");
THD *thd= ha_thd();
if (is_row_based_replication(thd))
rc= 0;
else
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_next(uchar * buf)
{
int rc;
DBUG_ENTER("ha_blackhole::index_next");
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_prev(uchar * buf)
{
int rc;
DBUG_ENTER("ha_blackhole::index_prev");
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_first(uchar * buf)
{
int rc;
DBUG_ENTER("ha_blackhole::index_first");
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
int ha_blackhole::index_last(uchar * buf)
{
int rc;
DBUG_ENTER("ha_blackhole::index_last");
rc= HA_ERR_END_OF_FILE;
DBUG_RETURN(rc);
}
static st_blackhole_share *get_share(const char *table_name)
{
st_blackhole_share *share;
uint length;
length= (uint) strlen(table_name);
mysql_mutex_lock(&blackhole_mutex);
if (!(share= (st_blackhole_share*)
my_hash_search(&blackhole_open_tables,
(uchar*) table_name, length)))
{
if (!(share= (st_blackhole_share*) my_malloc(sizeof(st_blackhole_share) +
length,
MYF(MY_WME | MY_ZEROFILL))))
goto error;
share->table_name_length= length;
strmov(share->table_name, table_name);
if (my_hash_insert(&blackhole_open_tables, (uchar*) share))
{
my_free(share);
share= NULL;
goto error;
}
thr_lock_init(&share->lock);
}
share->use_count++;
error:
mysql_mutex_unlock(&blackhole_mutex);
return share;
}
static void free_share(st_blackhole_share *share)
{
mysql_mutex_lock(&blackhole_mutex);
if (!--share->use_count)
my_hash_delete(&blackhole_open_tables, (uchar*) share);
mysql_mutex_unlock(&blackhole_mutex);
}
static void blackhole_free_key(st_blackhole_share *share)
{
thr_lock_delete(&share->lock);
my_free(share);
}
static uchar* blackhole_get_key(st_blackhole_share *share, size_t *length,
my_bool not_used __attribute__((unused)))
{
*length= share->table_name_length;
return (uchar*) share->table_name;
}
#ifdef HAVE_PSI_INTERFACE
static PSI_mutex_key bh_key_mutex_blackhole;
static PSI_mutex_info all_blackhole_mutexes[]=
{
{ &bh_key_mutex_blackhole, "blackhole", PSI_FLAG_GLOBAL}
};
void init_blackhole_psi_keys()
{
const char* category= "blackhole";
int count;
if (PSI_server == NULL)
return;
count= array_elements(all_blackhole_mutexes);
PSI_server->register_mutex(category, all_blackhole_mutexes, count);
}
#endif
static int blackhole_init(void *p)
{
handlerton *blackhole_hton;
#ifdef HAVE_PSI_INTERFACE
init_blackhole_psi_keys();
#endif
blackhole_hton= (handlerton *)p;
blackhole_hton->state= SHOW_OPTION_YES;
blackhole_hton->db_type= DB_TYPE_BLACKHOLE_DB;
blackhole_hton->create= blackhole_create_handler;
blackhole_hton->flags= HTON_CAN_RECREATE;
mysql_mutex_init(bh_key_mutex_blackhole,
&blackhole_mutex, MY_MUTEX_INIT_FAST);
(void) my_hash_init(&blackhole_open_tables, system_charset_info,32,0,0,
(my_hash_get_key) blackhole_get_key,
(my_hash_free_key) blackhole_free_key, 0);
return 0;
}
static int blackhole_fini(void *p)
{
my_hash_free(&blackhole_open_tables);
mysql_mutex_destroy(&blackhole_mutex);
return 0;
}
struct st_mysql_storage_engine blackhole_storage_engine=
{ MYSQL_HANDLERTON_INTERFACE_VERSION };
mysql_declare_plugin(blackhole)
{
MYSQL_STORAGE_ENGINE_PLUGIN,
&blackhole_storage_engine,
"BLACKHOLE",
"MySQL AB",
"/dev/null storage engine (anything you write to it disappears)",
PLUGIN_LICENSE_GPL,
blackhole_init, /* Plugin Init */
blackhole_fini, /* Plugin Deinit */
0x0100 /* 1.0 */,
NULL, /* status variables */
NULL, /* system variables */
NULL, /* config options */
0, /* flags */
}
mysql_declare_plugin_end;
maria_declare_plugin(blackhole)
{
MYSQL_STORAGE_ENGINE_PLUGIN,
&blackhole_storage_engine,
"BLACKHOLE",
"MySQL AB",
"/dev/null storage engine (anything you write to it disappears)",
PLUGIN_LICENSE_GPL,
blackhole_init, /* Plugin Init */
blackhole_fini, /* Plugin Deinit */
0x0100 /* 1.0 */,
NULL, /* status variables */
NULL, /* system variables */
"1.0", /* string version */
MariaDB_PLUGIN_MATURITY_STABLE /* maturity */
}
maria_declare_plugin_end;