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WL#5419 "LOCK_open scalability: make tdc_refresh_version

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an atomic counter"

Split the large LOCK_open section in open_table(). 
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.

This fixes
Bug#50589 "Server hang on a query evaluated using a temporary 
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler 
instances are created".

This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:

1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.

2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the 
internal HEAP engine share list until at least one
handler instance is created using that share.
This commit is contained in:
Konstantin Osipov
2010-06-11 19:28:18 +04:00
parent 218bf86cd9
commit b140456601
17 changed files with 207 additions and 146 deletions
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9
sql/sql_plugin.cc
View File

@@ -261,11 +261,6 @@ static plugin_ref intern_plugin_lock(LEX *lex, plugin_ref plugin
static void intern_plugin_unlock(LEX *lex, plugin_ref plugin);
static void reap_plugins(void);
#ifdef EMBEDDED_LIBRARY
/* declared in sql_base.cc */
extern bool check_if_table_exists(THD *thd, TABLE_LIST *table, bool *exists);
#endif /* EMBEDDED_LIBRARY */
static void report_error(int where_to, uint error, ...)
{
va_list args;
@@ -1475,10 +1470,8 @@ static void plugin_load(MEM_ROOT *tmp_root, int *argc, char **argv)
When building an embedded library, if the mysql.plugin table
does not exist, we silently ignore the missing table
*/
mysql_mutex_lock(&LOCK_open);
if (check_if_table_exists(new_thd, &tables, &table_exists))
table_exists= FALSE;
mysql_mutex_unlock(&LOCK_open);
if (!table_exists)
goto end;
#endif /* EMBEDDED_LIBRARY */
@@ -1519,7 +1512,7 @@ static void plugin_load(MEM_ROOT *tmp_root, int *argc, char **argv)
if (error > 0)
sql_print_error(ER(ER_GET_ERRNO), my_errno);
end_read_record(&read_record_info);
new_thd->version--; // Force close to free memory
table->m_needs_reopen= TRUE; // Force close to free memory
end:
close_thread_tables(new_thd);
/* Remember that we don't have a THD */