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/* Copyright (C) 2000-2006 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; 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Atomic rename of table; RENAME TABLE t1 to t2, tmp to t1 [,...]
*/
#include <drizzled/server_includes.h>
#include <drizzled/error.h>
#include <drizzled/table_list.h>
#include <drizzled/session.h>
#include <drizzled/lock.h>
#include "drizzled/rename.h"
static TableList *rename_tables(Session *session, TableList *table_list,
bool skip_error);
static TableList *reverse_table_list(TableList *table_list);
/*
Every second entry in the table_list is the original name and every
second entry is the new name.
*/
bool drizzle_rename_tables(Session *session, TableList *table_list)
{
bool error= true;
TableList *ren_table= NULL;
/*
Avoid problems with a rename on a table that we have locked or
if the user is trying to to do this in a transcation context
*/
if (session->inTransaction())
{
my_message(ER_LOCK_OR_ACTIVE_TRANSACTION, ER(ER_LOCK_OR_ACTIVE_TRANSACTION), MYF(0));
return true;
}
if (wait_if_global_read_lock(session,0,1))
return true;
pthread_mutex_lock(&LOCK_open); /* Rename table lock for exclusive access */
if (lock_table_names_exclusively(session, table_list))
{
pthread_mutex_unlock(&LOCK_open);
goto err;
}
error= false;
if ((ren_table=rename_tables(session,table_list,0)))
{
/* Rename didn't succeed; rename back the tables in reverse order */
TableList *table;
/* Reverse the table list */
table_list= reverse_table_list(table_list);
/* Find the last renamed table */
for (table= table_list;
table->next_local != ren_table ;
table= table->next_local->next_local) ;
table= table->next_local->next_local; // Skip error table
/* Revert to old names */
rename_tables(session, table, 1);
/* Revert the table list (for prepared statements) */
table_list= reverse_table_list(table_list);
error= true;
}
/*
An exclusive lock on table names is satisfactory to ensure
no other thread accesses this table.
We still should unlock LOCK_open as early as possible, to provide
higher concurrency - query_cache_invalidate can take minutes to
complete.
*/
pthread_mutex_unlock(&LOCK_open);
/* Lets hope this doesn't fail as the result will be messy */
if (!error)
{
write_bin_log(session, true, session->query, session->query_length);
session->my_ok();
}
pthread_mutex_lock(&LOCK_open); /* unlock all tables held */
unlock_table_names(table_list, NULL);
pthread_mutex_unlock(&LOCK_open);
err:
start_waiting_global_read_lock(session);
return error;
}
/*
reverse table list
SYNOPSIS
reverse_table_list()
table_list pointer to table _list
RETURN
pointer to new (reversed) list
*/
static TableList *reverse_table_list(TableList *table_list)
{
TableList *prev= NULL;
while (table_list)
{
TableList *next= table_list->next_local;
table_list->next_local= prev;
prev= table_list;
table_list= next;
}
return (prev);
}
/*
Rename a single table or a view
SYNPOSIS
do_rename()
session Thread handle
ren_table A table/view to be renamed
new_db The database to which the table to be moved to
new_table_name The new table/view name
skip_error Whether to skip error
DESCRIPTION
Rename a single table or a view.
RETURN
false Ok
true rename failed
*/
static bool
do_rename(Session *session, TableList *ren_table, const char *new_db, const char *new_table_name, bool skip_error)
{
bool rc= true;
const char *new_alias, *old_alias;
{
old_alias= ren_table->table_name;
new_alias= new_table_name;
}
StorageEngine *engine= NULL;
drizzled::message::Table table_proto;
char path[FN_REFLEN];
size_t length;
length= build_table_filename(path, sizeof(path),
ren_table->db, old_alias, false);
if (StorageEngine::getTableProto(path, &table_proto)!= EEXIST)
{
my_error(ER_NO_SUCH_TABLE, MYF(0), ren_table->db, old_alias);
return true;
}
engine= ha_resolve_by_name(session, table_proto.engine().name());
length= build_table_filename(path, sizeof(path),
new_db, new_alias, false);
if (StorageEngine::getTableProto(path, NULL)!=ENOENT)
{
my_error(ER_TABLE_EXISTS_ERROR, MYF(0), new_alias);
return(1); // This can't be skipped
}
rc= mysql_rename_table(engine,
ren_table->db, old_alias,
new_db, new_alias, 0);
if (rc && !skip_error)
return true;
return false;
}
/*
Rename all tables in list; Return pointer to wrong entry if something goes
wrong. Note that the table_list may be empty!
*/
/*
Rename tables/views in the list
SYNPOSIS
rename_tables()
session Thread handle
table_list List of tables to rename
skip_error Whether to skip errors
DESCRIPTION
Take a table/view name from and odd list element and rename it to a
the name taken from list element+1. Note that the table_list may be
empty.
RETURN
false Ok
true rename failed
*/
static TableList *
rename_tables(Session *session, TableList *table_list, bool skip_error)
{
TableList *ren_table, *new_table;
for (ren_table= table_list; ren_table; ren_table= new_table->next_local)
{
new_table= ren_table->next_local;
if (do_rename(session, ren_table, new_table->db, new_table->table_name, skip_error))
return(ren_table);
}
return(0);
}
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