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MDEV-9728 - Hard crash in metadata_lock_info
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Reverted APC based fix. APC subsystem is not ready to serve metadata_lock_info
needs.
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Sergey Vojtovich committed Jun 23, 2016
1 parent 26de906 commit 4abeebe
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Showing 2 changed files with 54 additions and 115 deletions.
167 changes: 53 additions & 114 deletions plugin/metadata_lock_info/metadata_lock_info.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,6 @@
#include "sql_class.h"
#include "sql_show.h"

I_List<THD> *thds;

static const LEX_STRING metadata_lock_info_lock_name[] = {
{ C_STRING_WITH_LEN("Global read lock") },
{ C_STRING_WITH_LEN("Schema metadata lock") },
Expand Down Expand Up @@ -69,135 +67,76 @@ static ST_FIELD_INFO i_s_metadata_lock_info_fields_info[] =
{NULL, 0, MYSQL_TYPE_STRING, 0, 0, NULL, 0}
};


class Ticket_info: public Apc_target::Apc_call
struct st_i_s_metadata_param
{
public:
bool timed_out;
THD *request_thd;
THD *target_thd;
THD *thd;
TABLE *table;
int error;

Ticket_info(THD *request_thd_arg, TABLE *table_arg):
request_thd(request_thd_arg), table(table_arg), error(0)
{ }

void call_in_target_thread()
{
MDL_ticket *ticket;
int i;

for (i= 0; i < MDL_DURATION_END; i++)
{
MDL_context::Ticket_iterator it(request_thd->mdl_context.m_tickets[i]);
while ((ticket= it++))
{
MDL_key *key= ticket->get_key();

table->field[0]->store((longlong) target_thd->thread_id, TRUE);

table->field[1]->set_notnull();
table->field[1]->store(
metadata_lock_info_lock_mode[(int) ticket->get_type()].str,
metadata_lock_info_lock_mode[(int) ticket->get_type()].length,
system_charset_info);

table->field[2]->set_notnull();
table->field[2]->store(
metadata_lock_info_duration[i].str,
metadata_lock_info_duration[i].length,
system_charset_info);

table->field[3]->set_notnull();
table->field[3]->store(
metadata_lock_info_lock_name[(int) key->mdl_namespace()].str,
metadata_lock_info_lock_name[(int) key->mdl_namespace()].length,
system_charset_info);

table->field[4]->set_notnull();
table->field[4]->store(key->db_name(), key->db_name_length(),
system_charset_info);

table->field[5]->set_notnull();
table->field[5]->store(key->name(), key->name_length(),
system_charset_info);

if ((error= schema_table_store_record(request_thd, table)))
return;
}
}
}
};


static THD *find_thread(my_thread_id id)
{
THD *tmp;

mysql_mutex_lock(&LOCK_thread_count);
I_List_iterator<THD> it(*thds);
while ((tmp= it++))
{
if (id == tmp->thread_id)
{
mysql_mutex_lock(&tmp->LOCK_thd_data);
break;
}
}
mysql_mutex_unlock(&LOCK_thread_count);
return tmp;
int i_s_metadata_lock_info_fill_row(
MDL_ticket *mdl_ticket,
void *arg
) {
st_i_s_metadata_param *param = (st_i_s_metadata_param *) arg;
THD *thd = param->thd;
TABLE *table = param->table;
DBUG_ENTER("i_s_metadata_lock_info_fill_row");
MDL_request mdl_request;
enum_mdl_duration mdl_duration;
MDL_context *mdl_ctx = mdl_ticket->get_ctx();
enum_mdl_type mdl_ticket_type = mdl_ticket->get_type();
MDL_key *mdl_key = mdl_ticket->get_key();
MDL_key::enum_mdl_namespace mdl_namespace = mdl_key->mdl_namespace();
mdl_request.init(mdl_key, mdl_ticket_type, MDL_STATEMENT);
mdl_ctx->find_ticket(&mdl_request, &mdl_duration);
table->field[0]->store((longlong) mdl_ctx->get_thread_id(), TRUE);
table->field[1]->set_notnull();
table->field[1]->store(
metadata_lock_info_lock_mode[(int) mdl_ticket_type].str,
metadata_lock_info_lock_mode[(int) mdl_ticket_type].length,
system_charset_info);
table->field[2]->set_notnull();
table->field[2]->store(
metadata_lock_info_duration[(int) mdl_duration].str,
metadata_lock_info_duration[(int) mdl_duration].length,
system_charset_info);
table->field[3]->set_notnull();
table->field[3]->store(
metadata_lock_info_lock_name[(int) mdl_namespace].str,
metadata_lock_info_lock_name[(int) mdl_namespace].length,
system_charset_info);
table->field[4]->set_notnull();
table->field[4]->store(mdl_key->db_name(),
mdl_key->db_name_length(), system_charset_info);
table->field[5]->set_notnull();
table->field[5]->store(mdl_key->name(),
mdl_key->name_length(), system_charset_info);
if (schema_table_store_record(thd, table))
DBUG_RETURN(1);
DBUG_RETURN(0);
}


static int i_s_metadata_lock_info_fill_table(THD *thd, TABLE_LIST *tables,
COND *cond)
{
Ticket_info info(thd, tables->table);
DYNAMIC_ARRAY ids;
THD *tmp;
uint i;
int i_s_metadata_lock_info_fill_table(
THD *thd,
TABLE_LIST *tables,
COND *cond
) {
st_i_s_metadata_param param;
DBUG_ENTER("i_s_metadata_lock_info_fill_table");

/* Gather thread identifiers */
my_init_dynamic_array(&ids, sizeof(my_thread_id), 512, 1, MYF(0));
mysql_mutex_lock(&LOCK_thread_count);
I_List_iterator<THD> it(*thds);
while ((tmp= it++))
if (tmp != thd && (info.error= insert_dynamic(&ids, &tmp->thread_id)))
break;
mysql_mutex_unlock(&LOCK_thread_count);

/* Let foreign threads fill info */
for (i= 0; i < ids.elements && info.error == 0; i++)
if ((info.target_thd= find_thread(*dynamic_element(&ids, i, my_thread_id*))))
info.target_thd->apc_target.make_apc_call(thd, &info, INT_MAX,
&info.timed_out);

delete_dynamic(&ids);
if (info.error == 0)
{
info.target_thd= thd;
info.call_in_target_thread();
}
DBUG_RETURN(info.error);
param.table = tables->table;
param.thd = thd;
DBUG_RETURN(mdl_iterate(i_s_metadata_lock_info_fill_row, &param));
}

static int i_s_metadata_lock_info_init(
void *p
) {
ST_SCHEMA_TABLE *schema = (ST_SCHEMA_TABLE *) p;
DBUG_ENTER("i_s_metadata_lock_info_init");
#ifdef _WIN32
thds = (I_List<THD>*)
GetProcAddress(GetModuleHandle(NULL), "?threads@@3V?$I_List@VTHD@@@@A");
#else
thds = &threads;
#endif
schema->fields_info = i_s_metadata_lock_info_fields_info;
schema->fill_table = i_s_metadata_lock_info_fill_table;
schema->idx_field1 = 0;
DBUG_RETURN(thds == 0);
DBUG_RETURN(0);
}

static int i_s_metadata_lock_info_deinit(
Expand Down
2 changes: 1 addition & 1 deletion sql/mdl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -953,7 +953,7 @@ class MDL_context
MDL_context &operator=(MDL_context &rhs); /* not implemented */

/* metadata_lock_info plugin */
friend class Ticket_info;
friend int i_s_metadata_lock_info_fill_row(MDL_ticket*, void*);
};


Expand Down

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