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mariadb/sql/sql_handler.cc
Jon Olav Hauglid 3eead1f0f1 Bug #51355 handler stmt cause assertion in 
bool MDL_context::try_acquire_lock(MDL_request*)

This assert was triggered in the following way:
1) HANDLER OPEN t1 from connection 1
2) DROP TABLE t1 from connection 2. This will block due to the metadata lock
held by the open handler in connection 1.
3) DML statement (e.g. INSERT) from connection 1. This will close the table
opened by the HANDLER in 1) and release its metadata lock. This is done due
to the pending exclusive metadata lock from 2). 
4) DROP TABLE t1 from connection 2 now completes and removes table t1.
5) HANDLER READ from connection 1. Since the handler table was closed in 3),
the handler code will try to reopen the table. First a new metadata lock on
t1 will be granted before the command fails since the table was removed in 4).
6) HANDLER READ from connection 1. This caused the assert.

The reason for the assert was that the MDL_request's pointer to the lock
ticket was not reset when the statement failed. HANDLER READ then tried to
acquire a lock using the same MDL_request object, triggering the assert.
This bug was only noticeable on debug builds and did not cause any problems
on release builds.

This patch fixes the problem by assuring that the pointer to the metadata 
lock ticket is reset when reopening of handler tables fails.

Test case added to handler.inc
2010-02-25 18:08:12 +01:00

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/* Copyright (C) 2000-2004 MySQL AB, 2008-2009 Sun Microsystems, Inc
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 */
/* HANDLER ... commands - direct access to ISAM */
/* 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...
*/
/*
The information about open HANDLER objects is stored in a HASH.
It holds objects of type TABLE_LIST, which are indexed by table
name/alias, and allows us to quickly find a HANDLER table for any
operation at hand - be it HANDLER READ or HANDLER CLOSE.
It also allows us to maintain an "open" HANDLER even in cases
when there is no physically open cursor. E.g. a FLUSH TABLE
statement in this or some other connection demands that all open
HANDLERs against the flushed table are closed. In order to
preserve the information about an open HANDLER, we don't perform
a complete HANDLER CLOSE, but only close the TABLE object. The
corresponding TABLE_LIST is kept in the cache with 'table'
pointer set to NULL. The table will be reopened on next access
(this, however, leads to loss of cursor position, unless the
cursor points at the first record).
*/
#include "mysql_priv.h"
#include "sql_select.h"
#include <assert.h>
#define HANDLER_TABLES_HASH_SIZE 120
static enum enum_ha_read_modes rkey_to_rnext[]=
{ RNEXT_SAME, RNEXT, RPREV, RNEXT, RPREV, RNEXT, RPREV, RPREV };
/*
Get hash key and hash key length.
SYNOPSIS
mysql_ha_hash_get_key()
tables Pointer to the hash object.
key_len_p (out) Pointer to the result for key length.
first Unused.
DESCRIPTION
The hash object is an TABLE_LIST struct.
The hash key is the alias name.
The hash key length is the alias name length plus one for the
terminateing NUL character.
RETURN
Pointer to the TABLE_LIST struct.
*/
static char *mysql_ha_hash_get_key(TABLE_LIST *tables, size_t *key_len_p,
my_bool first __attribute__((unused)))
{
*key_len_p= strlen(tables->alias) + 1 ; /* include '\0' in comparisons */
return tables->alias;
}
/*
Free an hash object.
SYNOPSIS
mysql_ha_hash_free()
tables Pointer to the hash object.
DESCRIPTION
The hash object is an TABLE_LIST struct.
RETURN
Nothing
*/
static void mysql_ha_hash_free(TABLE_LIST *tables)
{
my_free((char*) tables, MYF(0));
}
/**
Close a HANDLER table.
@param thd Thread identifier.
@param tables A list of tables with the first entry to close.
@note Though this function takes a list of tables, only the first list entry
will be closed.
@note Broadcasts refresh if it closed a table with old version.
*/
static void mysql_ha_close_table(THD *thd, TABLE_LIST *tables)
{
if (tables->table && !tables->table->s->tmp_table)
{
/* Non temporary table. */
tables->table->file->ha_index_or_rnd_end();
tables->table->open_by_handler= 0;
mysql_mutex_lock(&LOCK_open);
if (close_thread_table(thd, &tables->table))
{
/* Tell threads waiting for refresh that something has happened */
broadcast_refresh();
}
mysql_mutex_unlock(&LOCK_open);
thd->mdl_context.release_lock(tables->mdl_request.ticket);
}
else if (tables->table)
{
/* Must be a temporary table */
TABLE *table= tables->table;
table->file->ha_index_or_rnd_end();
table->query_id= thd->query_id;
table->open_by_handler= 0;
mark_tmp_table_for_reuse(table);
}
/* Mark table as closed, ready for re-open if necessary. */
tables->table= NULL;
/* Safety, cleanup the pointer to satisfy MDL assertions. */
tables->mdl_request.ticket= NULL;
}
/*
Open a HANDLER table.
SYNOPSIS
mysql_ha_open()
thd Thread identifier.
tables A list of tables with the first entry to open.
reopen Re-open a previously opened handler table.
DESCRIPTION
Though this function takes a list of tables, only the first list entry
will be opened.
'reopen' is set when a handler table is to be re-opened. In this case,
'tables' is the pointer to the hashed TABLE_LIST object which has been
saved on the original open.
'reopen' is also used to suppress the sending of an 'ok' message.
RETURN
FALSE OK
TRUE Error
*/
bool mysql_ha_open(THD *thd, TABLE_LIST *tables, bool reopen)
{
TABLE_LIST *hash_tables = NULL;
char *db, *name, *alias;
uint dblen, namelen, aliaslen, counter;
bool error;
TABLE *backup_open_tables;
MDL_ticket *mdl_savepoint;
DBUG_ENTER("mysql_ha_open");
DBUG_PRINT("enter",("'%s'.'%s' as '%s' reopen: %d",
tables->db, tables->table_name, tables->alias,
(int) reopen));
if (thd->locked_tables_mode)
{
my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
DBUG_RETURN(TRUE);
}
if (tables->schema_table)
{
my_error(ER_WRONG_USAGE, MYF(0), "HANDLER OPEN",
INFORMATION_SCHEMA_NAME.str);
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
if (! my_hash_inited(&thd->handler_tables_hash))
{
/*
HASH entries are of type TABLE_LIST.
*/
if (my_hash_init(&thd->handler_tables_hash, &my_charset_latin1,
HANDLER_TABLES_HASH_SIZE, 0, 0,
(my_hash_get_key) mysql_ha_hash_get_key,
(my_hash_free_key) mysql_ha_hash_free, 0))
{
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
}
else if (! reopen) /* Otherwise we have 'tables' already. */
{
if (my_hash_search(&thd->handler_tables_hash, (uchar*) tables->alias,
strlen(tables->alias) + 1))
{
DBUG_PRINT("info",("duplicate '%s'", tables->alias));
DBUG_PRINT("exit",("ERROR"));
my_error(ER_NONUNIQ_TABLE, MYF(0), tables->alias);
DBUG_RETURN(TRUE);
}
}
if (! reopen)
{
/* copy the TABLE_LIST struct */
dblen= strlen(tables->db) + 1;
namelen= strlen(tables->table_name) + 1;
aliaslen= strlen(tables->alias) + 1;
if (!(my_multi_malloc(MYF(MY_WME),
&hash_tables, (uint) sizeof(*hash_tables),
&db, (uint) dblen,
&name, (uint) namelen,
&alias, (uint) aliaslen,
NullS)))
{
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
/* structure copy */
*hash_tables= *tables;
hash_tables->db= db;
hash_tables->table_name= name;
hash_tables->alias= alias;
memcpy(hash_tables->db, tables->db, dblen);
memcpy(hash_tables->table_name, tables->table_name, namelen);
memcpy(hash_tables->alias, tables->alias, aliaslen);
hash_tables->mdl_request.init(MDL_key::TABLE, db, name, MDL_SHARED);
/* for now HANDLER can be used only for real TABLES */
hash_tables->required_type= FRMTYPE_TABLE;
/* add to hash */
if (my_hash_insert(&thd->handler_tables_hash, (uchar*) hash_tables))
{
my_free((char*) hash_tables, MYF(0));
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
}
else
hash_tables= tables;
/*
Save and reset the open_tables list so that open_tables() won't
be able to access (or know about) the previous list. And on return
from open_tables(), thd->open_tables will contain only the opened
table.
See open_table() back-off comments for more details.
*/
backup_open_tables= thd->open_tables;
thd->open_tables= NULL;
mdl_savepoint= thd->mdl_context.mdl_savepoint();
/*
open_tables() will set 'hash_tables->table' if successful.
It must be NULL for a real open when calling open_tables().
*/
DBUG_ASSERT(! hash_tables->table);
/*
We use open_tables() here, rather than, say,
open_ltable() or open_table() because we would like to be able
to open a temporary table.
*/
error= open_tables(thd, &hash_tables, &counter, 0);
if (! error &&
! (hash_tables->table->file->ha_table_flags() & HA_CAN_SQL_HANDLER))
{
my_error(ER_ILLEGAL_HA, MYF(0), tables->alias);
error= TRUE;
}
if (!error &&
hash_tables->mdl_request.ticket &&
thd->mdl_context.has_lock(mdl_savepoint,
hash_tables->mdl_request.ticket))
{
/* The ticket returned is within a savepoint. Make a copy. */
error= thd->mdl_context.clone_ticket(&hash_tables->mdl_request);
hash_tables->table->mdl_ticket= hash_tables->mdl_request.ticket;
}
if (error)
{
close_thread_tables(thd);
thd->open_tables= backup_open_tables;
thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
if (!reopen)
my_hash_delete(&thd->handler_tables_hash, (uchar*) hash_tables);
else
{
hash_tables->table= NULL;
/* Safety, cleanup the pointer to satisfy MDL assertions. */
hash_tables->mdl_request.ticket= NULL;
}
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
thd->open_tables= backup_open_tables;
if (hash_tables->mdl_request.ticket)
{
thd->mdl_context.
move_ticket_after_trans_sentinel(hash_tables->mdl_request.ticket);
thd->mdl_context.set_needs_thr_lock_abort(TRUE);
}
/*
Assert that the above check prevents opening of views and merge tables.
For temporary tables, TABLE::next can be set even if only one table
was opened for HANDLER as it is used to link them together
(see thd->temporary_tables).
*/
DBUG_ASSERT(hash_tables->table->next == NULL ||
hash_tables->table->s->tmp_table);
/*
If it's a temp table, don't reset table->query_id as the table is
being used by this handler. For non-temp tables we use this flag
in asserts.
*/
hash_tables->table->open_by_handler= 1;
if (! reopen)
my_ok(thd);
DBUG_PRINT("exit",("OK"));
DBUG_RETURN(FALSE);
}
/*
Close a HANDLER table by alias or table name
SYNOPSIS
mysql_ha_close()
thd Thread identifier.
tables A list of tables with the first entry to close.
DESCRIPTION
Closes the table that is associated (on the handler tables hash) with the
name (table->alias) of the specified table.
RETURN
FALSE ok
TRUE error
*/
bool mysql_ha_close(THD *thd, TABLE_LIST *tables)
{
TABLE_LIST *hash_tables;
DBUG_ENTER("mysql_ha_close");
DBUG_PRINT("enter",("'%s'.'%s' as '%s'",
tables->db, tables->table_name, tables->alias));
if (thd->locked_tables_mode)
{
my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
DBUG_RETURN(TRUE);
}
if ((hash_tables= (TABLE_LIST*) my_hash_search(&thd->handler_tables_hash,
(uchar*) tables->alias,
strlen(tables->alias) + 1)))
{
mysql_ha_close_table(thd, hash_tables);
my_hash_delete(&thd->handler_tables_hash, (uchar*) hash_tables);
}
else
{
my_error(ER_UNKNOWN_TABLE, MYF(0), tables->alias, "HANDLER");
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
/*
Mark MDL_context as no longer breaking protocol if we have
closed last HANDLER.
*/
if (! thd->handler_tables_hash.records)
thd->mdl_context.set_needs_thr_lock_abort(FALSE);
my_ok(thd);
DBUG_PRINT("exit", ("OK"));
DBUG_RETURN(FALSE);
}
/*
Read from a HANDLER table.
SYNOPSIS
mysql_ha_read()
thd Thread identifier.
tables A list of tables with the first entry to read.
mode
keyname
key_expr
ha_rkey_mode
cond
select_limit_cnt
offset_limit_cnt
RETURN
FALSE ok
TRUE error
*/
bool 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_cnt, ha_rows offset_limit_cnt)
{
TABLE_LIST *hash_tables;
TABLE *table, *backup_open_tables;
MYSQL_LOCK *lock;
List<Item> list;
Protocol *protocol= thd->protocol;
char buff[MAX_FIELD_WIDTH];
String buffer(buff, sizeof(buff), system_charset_info);
int error, keyno= -1;
uint num_rows;
uchar *UNINIT_VAR(key);
uint UNINIT_VAR(key_len);
bool need_reopen;
DBUG_ENTER("mysql_ha_read");
DBUG_PRINT("enter",("'%s'.'%s' as '%s'",
tables->db, tables->table_name, tables->alias));
if (thd->locked_tables_mode)
{
my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
DBUG_RETURN(TRUE);
}
thd->lex->select_lex.context.resolve_in_table_list_only(tables);
list.push_front(new Item_field(&thd->lex->select_lex.context,
NULL, NULL, "*"));
List_iterator<Item> it(list);
it++;
retry:
if ((hash_tables= (TABLE_LIST*) my_hash_search(&thd->handler_tables_hash,
(uchar*) tables->alias,
strlen(tables->alias) + 1)))
{
table= hash_tables->table;
DBUG_PRINT("info-in-hash",("'%s'.'%s' as '%s' table: 0x%lx",
hash_tables->db, hash_tables->table_name,
hash_tables->alias, (long) table));
if (!table)
{
/*
The handler table has been closed. Re-open it.
*/
if (mysql_ha_open(thd, hash_tables, 1))
{
DBUG_PRINT("exit",("reopen failed"));
goto err0;
}
table= hash_tables->table;
DBUG_PRINT("info",("re-opened '%s'.'%s' as '%s' tab %p",
hash_tables->db, hash_tables->table_name,
hash_tables->alias, table));
}
}
else
table= NULL;
if (!table)
{
my_error(ER_UNKNOWN_TABLE, MYF(0), tables->alias, "HANDLER");
goto err0;
}
/* save open_tables state */
backup_open_tables= thd->open_tables;
/* Always a one-element list, see mysql_ha_open(). */
DBUG_ASSERT(hash_tables->table->next == NULL ||
hash_tables->table->s->tmp_table);
/*
mysql_lock_tables() needs thd->open_tables to be set correctly to
be able to handle aborts properly.
*/
thd->open_tables= hash_tables->table;
lock= mysql_lock_tables(thd, &thd->open_tables, 1, 0, &need_reopen);
/*
In 5.1 and earlier, mysql_lock_tables() could replace the TABLE
object with another one (reopen it). This is no longer the case
with new MDL.
*/
DBUG_ASSERT(hash_tables->table == thd->open_tables);
/* Restore previous context. */
thd->open_tables= backup_open_tables;
if (need_reopen)
{
mysql_ha_close_table(thd, hash_tables);
goto retry;
}
if (!lock)
goto err0; // mysql_lock_tables() printed error message already
// Always read all columns
hash_tables->table->read_set= &hash_tables->table->s->all_set;
tables->table= hash_tables->table;
if (cond)
{
if (table->query_id != thd->query_id)
cond->cleanup(); // File was reopened
if ((!cond->fixed &&
cond->fix_fields(thd, &cond)) || cond->check_cols(1))
goto err;
}
if (keyname)
{
if ((keyno=find_type(keyname, &table->s->keynames, 1+2)-1)<0)
{
my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), keyname, tables->alias);
goto err;
}
}
if (insert_fields(thd, &thd->lex->select_lex.context,
tables->db, tables->alias, &it, 0))
goto err;
protocol->send_result_set_metadata(&list, Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF);
/*
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_cnt; )
{
switch (mode) {
case RNEXT:
if (table->file->inited != handler::NONE)
{
error=keyname ?
table->file->index_next(table->record[0]) :
table->file->rnd_next(table->record[0]);
break;
}
/* else fall through */
case RFIRST:
if (keyname)
{
table->file->ha_index_or_rnd_end();
table->file->ha_index_init(keyno, 1);
error= table->file->index_first(table->record[0]);
}
else
{
table->file->ha_index_or_rnd_end();
if (!(error= table->file->ha_rnd_init(1)))
error= table->file->rnd_next(table->record[0]);
}
mode=RNEXT;
break;
case RPREV:
DBUG_ASSERT(keyname != 0);
if (table->file->inited != handler::NONE)
{
error=table->file->index_prev(table->record[0]);
break;
}
/* else fall through */
case RLAST:
DBUG_ASSERT(keyname != 0);
table->file->ha_index_or_rnd_end();
table->file->ha_index_init(keyno, 1);
error= table->file->index_last(table->record[0]);
mode=RPREV;
break;
case RNEXT_SAME:
/* Continue scan on "(keypart1,keypart2,...)=(c1, c2, ...) */
DBUG_ASSERT(keyname != 0);
error= 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_error(ER_TOO_MANY_KEY_PARTS, MYF(0), keyinfo->key_parts);
goto err;
}
List_iterator<Item> it_ke(*key_expr);
Item *item;
key_part_map keypart_map;
for (keypart_map= key_len=0 ; (item=it_ke++) ; key_part++)
{
my_bitmap_map *old_map;
// 'item' can be changed by fix_fields() call
if ((!item->fixed &&
item->fix_fields(thd, 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;
}
old_map= dbug_tmp_use_all_columns(table, table->write_set);
(void) item->save_in_field(key_part->field, 1);
dbug_tmp_restore_column_map(table->write_set, old_map);
key_len+=key_part->store_length;
keypart_map= (keypart_map << 1) | 1;
}
if (!(key= (uchar*) thd->calloc(ALIGN_SIZE(key_len))))
goto err;
table->file->ha_index_or_rnd_end();
table->file->ha_index_init(keyno, 1);
key_copy(key, table->record[0], table->key_info + keyno, key_len);
error= table->file->index_read_map(table->record[0],
key, keypart_map, ha_rkey_mode);
mode=rkey_to_rnext[(int)ha_rkey_mode];
break;
}
default:
my_message(ER_ILLEGAL_HA, ER(ER_ILLEGAL_HA), MYF(0));
goto err;
}
if (error)
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
{
sql_print_error("mysql_ha_read: Got error %d when reading table '%s'",
error, tables->table_name);
table->file->print_error(error,MYF(0));
goto err;
}
goto ok;
}
if (cond && !cond->val_int())
continue;
if (num_rows >= offset_limit_cnt)
{
protocol->prepare_for_resend();
if (protocol->send_result_set_row(&list))
goto err;
protocol->write();
}
num_rows++;
}
ok:
mysql_unlock_tables(thd,lock);
my_eof(thd);
DBUG_PRINT("exit",("OK"));
DBUG_RETURN(FALSE);
err:
mysql_unlock_tables(thd,lock);
err0:
DBUG_PRINT("exit",("ERROR"));
DBUG_RETURN(TRUE);
}
/**
Scan the handler tables hash for matching tables.
@param thd Thread identifier.
@param tables The list of tables to remove.
@return Pointer to head of linked list (TABLE_LIST::next_local) of matching
TABLE_LIST elements from handler_tables_hash. Otherwise, NULL if no
table was matched.
*/
static TABLE_LIST *mysql_ha_find(THD *thd, TABLE_LIST *tables)
{
TABLE_LIST *hash_tables, *head= NULL, *first= tables;
DBUG_ENTER("mysql_ha_find");
/* search for all handlers with matching table names */
for (uint i= 0; i < thd->handler_tables_hash.records; i++)
{
hash_tables= (TABLE_LIST*) my_hash_element(&thd->handler_tables_hash, i);
for (tables= first; tables; tables= tables->next_local)
{
if ((! *tables->db ||
! my_strcasecmp(&my_charset_latin1, hash_tables->db, tables->db)) &&
! my_strcasecmp(&my_charset_latin1, hash_tables->table_name,
tables->table_name))
break;
}
if (tables)
{
hash_tables->next_local= head;
head= hash_tables;
}
}
DBUG_RETURN(head);
}
/**
Remove matching tables from the HANDLER's hash table.
@param thd Thread identifier.
@param tables The list of tables to remove.
@note Broadcasts refresh if it closed a table with old version.
*/
void mysql_ha_rm_tables(THD *thd, TABLE_LIST *tables)
{
TABLE_LIST *hash_tables, *next;
DBUG_ENTER("mysql_ha_rm_tables");
DBUG_ASSERT(tables);
hash_tables= mysql_ha_find(thd, tables);
while (hash_tables)
{
next= hash_tables->next_local;
if (hash_tables->table)
mysql_ha_close_table(thd, hash_tables);
my_hash_delete(&thd->handler_tables_hash, (uchar*) hash_tables);
hash_tables= next;
}
/*
Mark MDL_context as no longer breaking protocol if we have
closed last HANDLER.
*/
if (! thd->handler_tables_hash.records)
thd->mdl_context.set_needs_thr_lock_abort(FALSE);
DBUG_VOID_RETURN;
}
/**
Flush (close and mark for re-open) all tables that should be should
be reopen.
@param thd Thread identifier.
@note Broadcasts refresh if it closed a table with old version.
*/
void mysql_ha_flush(THD *thd)
{
TABLE_LIST *hash_tables;
DBUG_ENTER("mysql_ha_flush");
mysql_mutex_assert_not_owner(&LOCK_open);
/*
Don't try to flush open HANDLERs when we're working with
system tables. The main MDL context is backed up and we can't
properly release HANDLER locks stored there.
*/
if (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)
DBUG_VOID_RETURN;
for (uint i= 0; i < thd->handler_tables_hash.records; i++)
{
hash_tables= (TABLE_LIST*) my_hash_element(&thd->handler_tables_hash, i);
/*
TABLE::mdl_ticket is 0 for temporary tables so we need extra check.
*/
if (hash_tables->table &&
((hash_tables->table->mdl_ticket &&
hash_tables->table->mdl_ticket->has_pending_conflicting_lock()) ||
(!hash_tables->table->s->tmp_table &&
hash_tables->table->s->needs_reopen())))
mysql_ha_close_table(thd, hash_tables);
}
DBUG_VOID_RETURN;
}
/**
Close all HANDLER's tables.
@param thd Thread identifier.
@note Broadcasts refresh if it closed a table with old version.
*/
void mysql_ha_cleanup(THD *thd)
{
TABLE_LIST *hash_tables;
DBUG_ENTER("mysql_ha_cleanup");
for (uint i= 0; i < thd->handler_tables_hash.records; i++)
{
hash_tables= (TABLE_LIST*) my_hash_element(&thd->handler_tables_hash, i);
if (hash_tables->table)
mysql_ha_close_table(thd, hash_tables);
}
my_hash_free(&thd->handler_tables_hash);
DBUG_VOID_RETURN;
}
/**
Move tickets for metadata locks corresponding to open HANDLERs
after transaction sentinel in order to protect them from being
released at the end of transaction.
@param thd Thread identifier.
*/
void mysql_ha_move_tickets_after_trans_sentinel(THD *thd)
{
TABLE_LIST *hash_tables;
DBUG_ENTER("mysql_ha_move_tickets_after_trans_sentinel");
for (uint i= 0; i < thd->handler_tables_hash.records; i++)
{
hash_tables= (TABLE_LIST*) my_hash_element(&thd->handler_tables_hash, i);
if (hash_tables->table && hash_tables->table->mdl_ticket)
thd->mdl_context.
move_ticket_after_trans_sentinel(hash_tables->table->mdl_ticket);
}
DBUG_VOID_RETURN;
}
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