/* Copyright (C) 2000-2003 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 */
/* HANDLER ... commands - direct access to ISAM */
#include "mysql_priv.h"
#include "sql_select.h"
/* TODO:
HANDLER blabla OPEN [ AS foobar ] [ (column-list) ]
the most natural (easiest, fastest) way to do it is to
compute List<Item> field_list not in mysql_ha_read
but in mysql_ha_open, and then store it in TABLE structure.
The problem here is that mysql_parse calls free_item to free all the
items allocated at the end of every query. The workaround would to
keep two item lists per THD - normal free_list and handler_items.
The second is to be freeed only on thread end. mysql_ha_open should
then do { handler_items=concat(handler_items, free_list); free_list=0; }
But !!! do_command calls free_root at the end of every query and frees up
all the sql_alloc'ed memory. It's harder to work around...
*/
#define HANDLER_TABLES_HACK(thd) { \
TABLE *tmp=thd->open_tables; \
thd->open_tables=thd->handler_tables; \
thd->handler_tables=tmp; }
static TABLE **find_table_ptr_by_name(THD *thd,const char *db,
const char *table_name,
bool is_alias, bool dont_lock,
bool *was_flushed);
int mysql_ha_open(THD *thd, TABLE_LIST *tables)
{
HANDLER_TABLES_HACK(thd);
uint counter;
int err=open_tables(thd, tables, &counter);
HANDLER_TABLES_HACK(thd);
if (err)
return -1;
// there can be only one table in *tables
if (!(tables->table->file->table_flags() & HA_CAN_SQL_HANDLER))
{
my_printf_error(ER_ILLEGAL_HA,ER(ER_ILLEGAL_HA),MYF(0), tables->alias);
mysql_ha_close(thd, tables,1);
return -1;
}
send_ok(thd);
return 0;
}
/*
Close a HANDLER table.
SYNOPSIS
mysql_ha_close()
thd Thread identifier.
tables A list of tables with the first entry to close.
dont_send_ok Suppresses the commands' ok message and
error message and error return.
dont_lock Suppresses the normal locking of LOCK_open.
DESCRIPTION
Though this function takes a list of tables, only the first list entry
will be closed. Broadcasts a COND_refresh condition.
If mysql_ha_close() is not called from the parser, 'dont_send_ok'
must be set.
If the caller did already lock LOCK_open, it must set 'dont_lock'.
IMPLEMENTATION
find_table_ptr_by_name() closes the table, if a FLUSH TABLE is outstanding.
It returns a NULL pointer in this case, but flags the situation in
'was_flushed'. In that case the normal ER_UNKNOWN_TABLE error messages
is suppressed.
RETURN
0 ok
-1 error
*/
int mysql_ha_close(THD *thd, TABLE_LIST *tables,
bool dont_send_ok, bool dont_lock, bool no_alias)
{
TABLE **table_ptr;
bool was_flushed;
table_ptr= find_table_ptr_by_name(thd, tables->db, tables->alias,
!no_alias, dont_lock, &was_flushed);
if (*table_ptr)
{
(*table_ptr)->file->ha_index_or_rnd_end();
if (!dont_lock)
VOID(pthread_mutex_lock(&LOCK_open));
if (close_thread_table(thd, table_ptr))
{
/* Tell threads waiting for refresh that something has happened */
VOID(pthread_cond_broadcast(&COND_refresh));
}
if (!dont_lock)
VOID(pthread_mutex_unlock(&LOCK_open));
}
else if (!was_flushed && !dont_send_ok)
{
my_printf_error(ER_UNKNOWN_TABLE, ER(ER_UNKNOWN_TABLE), MYF(0),
tables->alias, "HANDLER");
return -1;
}
if (!dont_send_ok)
send_ok(thd);
return 0;
}
/*
Close a list of HANDLER tables.
SYNOPSIS
mysql_ha_close_list()
thd Thread identifier.
tables The list of tables to close. If NULL,
close all HANDLER tables.
flushed Close only tables which are marked flushed.
Used only if tables is NULL.
DESCRIPTION
The list of HANDLER tables may be NULL, in which case all HANDLER
tables are closed. Broadcasts a COND_refresh condition, for
every table closed. If 'tables' is NULL and 'flushed' is set,
all HANDLER tables marked for flush are closed.
The caller must lock LOCK_open.
IMPLEMENTATION
find_table_ptr_by_name() closes the table, if it is marked for flush.
It returns a NULL pointer in this case, but flags the situation in
'was_flushed'. In that case the normal ER_UNKNOWN_TABLE error messages
is suppressed.
RETURN
0 ok
*/
int mysql_ha_close_list(THD *thd, TABLE_LIST *tables, bool flushed)
{
TABLE_LIST *tl_item;
TABLE **table_ptr;
if (tables)
{
for (tl_item= tables ; tl_item; tl_item= tl_item->next_local)
{
mysql_ha_close(thd, tl_item, /*dont_send_ok*/ 1,
/*dont_lock*/ 1, /*no_alias*/ 1);
}
}
else
{
table_ptr= &(thd->handler_tables);
while (*table_ptr)
{
if (! flushed || ((*table_ptr)->version != refresh_version))
{
(*table_ptr)->file->ha_index_or_rnd_end();
if (close_thread_table(thd, table_ptr))
{
/* Tell threads waiting for refresh that something has happened */
VOID(pthread_cond_broadcast(&COND_refresh));
}
continue;
}
table_ptr= &((*table_ptr)->next);
}
}
return 0;
}
static enum enum_ha_read_modes rkey_to_rnext[]=
{ RNEXT_SAME, RNEXT, RPREV, RNEXT, RPREV, RNEXT, RPREV, RPREV };
int mysql_ha_read(THD *thd, TABLE_LIST *tables,
enum enum_ha_read_modes mode, char *keyname,
List<Item> *key_expr,
enum ha_rkey_function ha_rkey_mode, Item *cond,
ha_rows select_limit,ha_rows offset_limit)
{
int err, keyno=-1;
bool was_flushed;
TABLE *table= *find_table_ptr_by_name(thd, tables->db, tables->alias,
/*is_alias*/ 1, /*dont_lock*/ 0,
&was_flushed);
if (!table)
{
my_printf_error(ER_UNKNOWN_TABLE,ER(ER_UNKNOWN_TABLE),MYF(0),
tables->alias,"HANDLER");
return -1;
}
tables->table=table;
if (cond && (cond->fix_fields(thd, tables, &cond) || cond->check_cols(1)))
return -1;
/* InnoDB needs to know that this table handle is used in the HANDLER */
table->file->init_table_handle_for_HANDLER();
if (keyname)
{
if ((keyno=find_type(keyname, &table->keynames, 1+2)-1)<0)
{
my_printf_error(ER_KEY_DOES_NOT_EXITS,ER(ER_KEY_DOES_NOT_EXITS),MYF(0),
keyname,tables->alias);
return -1;
}
table->file->ha_index_or_rnd_end();
table->file->ha_index_init(keyno);
}
List<Item> list;
list.push_front(new Item_field(NULL,NULL,"*"));
List_iterator<Item> it(list);
Protocol *protocol= thd->protocol;
char buff[MAX_FIELD_WIDTH];
String buffer(buff, sizeof(buff), system_charset_info);
uint num_rows;
byte *key;
uint key_len;
LINT_INIT(key);
LINT_INIT(key_len);
it++; // Skip first NULL field
insert_fields(thd, tables, tables->db, tables->alias, &it, 0);
select_limit+=offset_limit;
protocol->send_fields(&list,1);
HANDLER_TABLES_HACK(thd);
MYSQL_LOCK *lock=mysql_lock_tables(thd,&tables->table,1);
HANDLER_TABLES_HACK(thd);
if (!lock)
goto err0; // mysql_lock_tables() printed error message already
/*
In ::external_lock InnoDB resets the fields which tell it that
the handle is used in the HANDLER interface. Tell it again that
we are using it for HANDLER.
*/
table->file->init_table_handle_for_HANDLER();
for (num_rows=0; num_rows < select_limit; )
{
switch (mode) {
case RFIRST:
if (keyname)
err=table->file->index_first(table->record[0]);
else
{
table->file->ha_index_or_rnd_end();
if (!(err=table->file->ha_rnd_init(1)))
err=table->file->rnd_next(table->record[0]);
}
mode=RNEXT;
break;
case RLAST:
DBUG_ASSERT(keyname != 0);
err=table->file->index_last(table->record[0]);
mode=RPREV;
break;
case RNEXT:
err=keyname ?
table->file->index_next(table->record[0]) :
table->file->rnd_next(table->record[0]);
break;
case RPREV:
DBUG_ASSERT(keyname != 0);
err=table->file->index_prev(table->record[0]);
break;
case RNEXT_SAME:
/* Continue scan on "(keypart1,keypart2,...)=(c1, c2, ...) */
DBUG_ASSERT(keyname != 0);
err= table->file->index_next_same(table->record[0], key, key_len);
break;
case RKEY:
{
DBUG_ASSERT(keyname != 0);
KEY *keyinfo=table->key_info+keyno;
KEY_PART_INFO *key_part=keyinfo->key_part;
if (key_expr->elements > keyinfo->key_parts)
{
my_printf_error(ER_TOO_MANY_KEY_PARTS,ER(ER_TOO_MANY_KEY_PARTS),
MYF(0),keyinfo->key_parts);
goto err;
}
List_iterator<Item> it_ke(*key_expr);
Item *item;
for (key_len=0 ; (item=it_ke++) ; key_part++)
{
// 'item' can be changed by fix_fields() call
if (item->fix_fields(thd, tables, it_ke.ref()) ||
(item= *it_ke.ref())->check_cols(1))
goto err;
if (item->used_tables() & ~RAND_TABLE_BIT)
{
my_error(ER_WRONG_ARGUMENTS,MYF(0),"HANDLER ... READ");
goto err;
}
(void) item->save_in_field(key_part->field, 1);
key_len+=key_part->store_length;
}
if (!(key= (byte*) thd->calloc(ALIGN_SIZE(key_len))))
{
send_error(thd,ER_OUTOFMEMORY);
goto err;
}
key_copy(key, table, keyno, key_len);
err=table->file->index_read(table->record[0],
key,key_len,ha_rkey_mode);
mode=rkey_to_rnext[(int)ha_rkey_mode];
break;
}
default:
send_error(thd,ER_ILLEGAL_HA);
goto err;
}
if (err == HA_ERR_RECORD_DELETED)
continue;
if (err)
{
if (err != HA_ERR_KEY_NOT_FOUND && err != HA_ERR_END_OF_FILE)
{
sql_print_error("mysql_ha_read: Got error %d when reading table '%s'",
err, tables->real_name);
table->file->print_error(err,MYF(0));
goto err;
}
goto ok;
}
if (cond && !cond->val_int())
continue;
if (num_rows >= offset_limit)
{
Item *item;
protocol->prepare_for_resend();
it.rewind();
while ((item=it++))
{
if (item->send(thd->protocol, &buffer))
{
protocol->free(); // Free used
my_error(ER_OUT_OF_RESOURCES,MYF(0));
goto err;
}
}
protocol->write();
}
num_rows++;
}
ok:
mysql_unlock_tables(thd,lock);
send_eof(thd);
return 0;
err:
mysql_unlock_tables(thd,lock);
err0:
return -1;
}
/*
Find a HANDLER table by name.
SYNOPSIS
find_table_ptr_by_name()
thd Thread identifier.
db Database (schema) name.
table_name Table name ;-).
is_alias Table name may be an alias name.
dont_lock Suppresses the normal locking of LOCK_open.
DESCRIPTION
Find the table 'db'.'table_name' in the list of HANDLER tables of the
thread 'thd'. If the table has been marked by FLUSH TABLE(S), close it,
flag this situation in '*was_flushed' and broadcast a COND_refresh
condition.
An empty database (schema) name matches all database (schema) names.
If the caller did already lock LOCK_open, it must set 'dont_lock'.
IMPLEMENTATION
Just in case that the table is twice in 'thd->handler_tables' (!?!),
the loop does not break when the table was flushed. If another table
by that name was found and not flushed, '*was_flushed' is cleared again,
since a pointer to an open HANDLER table is returned.
RETURN
*was_flushed Table has been closed due to FLUSH TABLE.
NULL A HANDLER Table by that name does not exist (any more).
!= NULL Pointer to the TABLE structure.
*/
static TABLE **find_table_ptr_by_name(THD *thd, const char *db,
const char *table_name,
bool is_alias, bool dont_lock,
bool *was_flushed)
{
int dblen;
TABLE **table_ptr;
DBUG_ASSERT(db);
dblen= strlen(db);
table_ptr= &(thd->handler_tables);
*was_flushed= FALSE;
for (TABLE *table= *table_ptr; table ; table= *table_ptr)
{
if ((db == any_db || !memcmp(table->table_cache_key, db, dblen)) &&
!my_strcasecmp(system_charset_info,
(is_alias ? table->table_name : table->real_name),
table_name))
{
if (table->version != refresh_version)
{
if (!dont_lock)
VOID(pthread_mutex_lock(&LOCK_open));
table->file->ha_index_or_rnd_end();
if (close_thread_table(thd, table_ptr))
{
/* Tell threads waiting for refresh that something has happened */
VOID(pthread_cond_broadcast(&COND_refresh));
}
if (!dont_lock)
VOID(pthread_mutex_unlock(&LOCK_open));
*was_flushed= TRUE;
continue;
}
*was_flushed= FALSE;
break;
}
table_ptr= &(table->next);
}
return table_ptr;
}