database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Fix for bug#19403/12212 "Crash that happens during removing of database name

Browse Source 
from cache" and #21216 "Simultaneous DROP TABLE and SHOW OPEN TABLES causes
server to crash".

Crash happened when one ran DROP DATABASE or SHOW OPEN TABLES statements
while concurrently doing DROP TABLE (or RENAME TABLE, CREATE TABLE LIKE
or any other command that takes name-lock) in other connection.

This problem was caused by the fact that table placeholders which were
added to table cache in order to obtain name-lock on table had
TABLE_SHARE::db and table_name set to 0. Therefore they broke assumption
that these members are non-0 for all tables in table cache on which some
of our code relies.

The fix sets these members for such placeholders to appropriate value making
this assumption true again. As attempt to avoid such problems in future
we introduce auxiliary TABLE_SHARE::set_table_cache_key() methods which
should be used when one wants to set TABLE_SHARE::table_cache_key and which
ensure that TABLE_SHARE::table_name/db are set properly.

Test cases for these bugs were added to 5.0 test-suite (with 5.0-specific
fix for bug #21216).
This commit is contained in:
dlenev@mockturtle.local
2006-08-21 19:02:11 +04:00
parent a486f95547
commit 8fb55ff0cf
5 changed files with 95 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
sql/sql_base.cc
View File

@ -634,6 +634,7 @@ TABLE_SHARE *get_cached_table_share(const char *db, const char *table_name)
static void close_handle_and_leave_table_as_lock(TABLE *table)
{
TABLE_SHARE *share, *old_share= table->s;
char *key_buff;
MEM_ROOT *mem_root= &table->mem_root;
DBUG_ENTER("close_handle_and_leave_table_as_lock");
@ -642,20 +643,14 @@ static void close_handle_and_leave_table_as_lock(TABLE *table)
This has to be done to ensure that the table share is removed from
the table defintion cache as soon as the last instance is removed
*/
if ((share= (TABLE_SHARE*) alloc_root(mem_root, sizeof(*share))))
if (multi_alloc_root(mem_root,
&share, sizeof(*share),
&key_buff, old_share->table_cache_key.length,
NULL))
{
bzero((char*) share, sizeof(*share));
share->db.str= memdup_root(mem_root, old_share->db.str,
old_share->db.length+1);
share->db.length= old_share->db.length;
share->table_name.str= memdup_root(mem_root,
old_share->table_name.str,
old_share->table_name.length+1);
share->table_name.length= old_share->table_name.length;
share->table_cache_key.str= memdup_root(mem_root,
old_share->table_cache_key.str,
old_share->table_cache_key.length);
share->table_cache_key.length= old_share->table_cache_key.length;
share->set_table_cache_key(key_buff, old_share->table_cache_key.str,
old_share->table_cache_key.length);
share->tmp_table= INTERNAL_TMP_TABLE; // for intern_close_table()
}
@ -1603,28 +1598,18 @@ bool rename_temporary_table(THD* thd, TABLE *table, const char *db,
const char *table_name)
{
char *key;
uint key_length;
TABLE_SHARE *share= table->s;
TABLE_LIST table_list;
uint db_length, table_length;
DBUG_ENTER("rename_temporary_table");
if (!(key=(char*) alloc_root(&share->mem_root,
(uint) (db_length= strlen(db))+
(uint) (table_length= strlen(table_name))+6+4)))
if (!(key=(char*) alloc_root(&share->mem_root, MAX_DBKEY_LENGTH)))
DBUG_RETURN(1); /* purecov: inspected */
table_list.db= (char*) db;
table_list.table_name= (char*) table_name;
share->db.str= share->table_cache_key.str= key;
share->db.length= db_length;
share->table_cache_key.length= create_table_def_key(thd, key,
&table_list, 1);
/*
Here we use the fact that table_name is stored as the second component
in the 'key' (after db_name), where components are separated with \0
*/
share->table_name.str= key+db_length+1;
share->table_name.length= table_length;
key_length= create_table_def_key(thd, key, &table_list, 1);
share->set_table_cache_key(key, key_length);
DBUG_RETURN(0);
}
@ -1749,10 +1734,7 @@ bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
{
TABLE *table= table_list->table;
TABLE_SHARE *share;
char *db= table_list->db;
char *table_name= table_list->table_name;
char key[MAX_DBKEY_LENGTH];
uint key_length;
TABLE orig_table;
DBUG_ENTER("reopen_name_locked_table");
@ -1762,7 +1744,6 @@ bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
DBUG_RETURN(TRUE);
orig_table= *table;
key_length=(uint) (strmov(strmov(key,db)+1,table_name)-key)+1;
if (open_unireg_entry(thd, table, table_list, table_name,
table->s->table_cache_key.str,