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Commit c926610d authored by He Zhenxing's avatar He Zhenxing
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Bug#49020 Semi-sync master crashed with free_pool == NULL, assertion `free_pool_' 

Before this patch, semisync assumed transactions running in parallel
can not be larger than max_connections, but this is not true when
the event scheduler is executing events, and cause semisync run out
of preallocated transaction nodes.

Fix the problem by allocating transaction nodes dynamically.

This patch also fixed a possible deadlock when running UNINSTALL
PLUGIN rpl_semi_sync_master and updating in parallel. Fixed by
releasing the internal Delegate lock before unlock the plugins.

mysql-test/suite/rpl/t/rpl_semi_sync_event.test:
  Add test case for bug#49020
plugin/semisync/semisync_master.cc:
  Allocating TranxNode dynamically
plugin/semisync/semisync_master.h:
  Allocating TranxNode dynamically
sql/rpl_handler.cc:
  Unlock plugins after we have released the Delegate lock to avoid possible deadlock when uninstalling semisync master plugin and doing update in parallel.
parent a02972d8
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Showing with 213 additions and 85 deletions
mysql-test/suite/rpl/r/rpl_semi_sync_event.result 0 → 100644
View file @ c926610d
stop slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
reset master;
reset slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
start slave;
include/stop_slave.inc
include/start_slave.inc
SET GLOBAL event_scheduler = ON;
CREATE TABLE t1 (i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f varchar(8)) ENGINE=ENGINE_TYPE;
INSERT INTO t1 (f) VALUES ('a'),('a'),('a'),('a'),('a');
INSERT INTO t1 SELECT i+5, f FROM t1;
INSERT INTO t1 SELECT i+10, f FROM t1;
CREATE EVENT ev1 ON SCHEDULE EVERY 1 SECOND
DO INSERT INTO t1 VALUES (SLEEP(5),CONCAT('ev1_',CONNECTION_ID()));
CREATE EVENT ev2 ON SCHEDULE EVERY 1 SECOND
DO INSERT INTO t1 VALUES (SLEEP(5),CONCAT('ev2_',CONNECTION_ID()));
STOP SLAVE IO_THREAD;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 20;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 19;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 18;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 17;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 16;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 15;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 14;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 13;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 12;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 11;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 10;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 9;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 8;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 7;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 6;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 5;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 4;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 3;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 2;
UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = 1;
SET GLOBAL event_scheduler = OFF;
include/stop_slave.inc
UNINSTALL PLUGIN rpl_semi_sync_slave;
UNINSTALL PLUGIN rpl_semi_sync_master;
include/start_slave.inc
DROP EVENT ev1;
DROP EVENT ev2;
DROP TABLE t1;
mysql-test/suite/rpl/t/rpl_semi_sync_event-master.opt 0 → 100644
View file @ c926610d
$SEMISYNC_PLUGIN_OPT --max-connections=23
mysql-test/suite/rpl/t/rpl_semi_sync_event.test 0 → 100644
View file @ c926610d
source include/have_semisync_plugin.inc;
source include/not_embedded.inc;
source include/master-slave.inc;
source include/have_innodb.inc;
let $engine_type= InnoDB;
# Suppress warnings that might be generated during the test
disable_query_log;
connection master;
call mtr.add_suppression("Timeout waiting for reply of binlog");
call mtr.add_suppression("Semi-sync master .* waiting for slave reply");
call mtr.add_suppression("Read semi-sync reply");
connection slave;
call mtr.add_suppression("Master server does not support semi-sync");
call mtr.add_suppression("Semi-sync slave .* reply");
enable_query_log;
connection master;
disable_query_log;
let $value = query_get_value(show variables like 'rpl_semi_sync_master_enabled', Value, 1);
if (`select '$value' = 'No such row'`)
{
set sql_log_bin=0;
eval INSTALL PLUGIN rpl_semi_sync_master SONAME '$SEMISYNC_MASTER_PLUGIN';
SET GLOBAL rpl_semi_sync_master_enabled = 1;
set sql_log_bin=1;
}
enable_query_log;
connection slave;
source include/stop_slave.inc;
disable_query_log;
let $value= query_get_value(show variables like 'rpl_semi_sync_slave_enabled', Value, 1);
if (`select '$value' = 'No such row'`)
{
set sql_log_bin=0;
eval INSTALL PLUGIN rpl_semi_sync_slave SONAME '$SEMISYNC_SLAVE_PLUGIN';
SET GLOBAL rpl_semi_sync_slave_enabled = 1;
set sql_log_bin=1;
}
enable_query_log;
source include/start_slave.inc;
connection master;
SET GLOBAL event_scheduler = ON;
replace_result $engine_type ENGINE_TYPE;
eval CREATE TABLE t1 (i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f varchar(8)) ENGINE=$engine_type;
INSERT INTO t1 (f) VALUES ('a'),('a'),('a'),('a'),('a');
INSERT INTO t1 SELECT i+5, f FROM t1;
INSERT INTO t1 SELECT i+10, f FROM t1;
CREATE EVENT ev1 ON SCHEDULE EVERY 1 SECOND
DO INSERT INTO t1 VALUES (SLEEP(5),CONCAT('ev1_',CONNECTION_ID()));
CREATE EVENT ev2 ON SCHEDULE EVERY 1 SECOND
DO INSERT INTO t1 VALUES (SLEEP(5),CONCAT('ev2_',CONNECTION_ID()));
connection slave;
STOP SLAVE IO_THREAD;
connection master;
let $run = 20;
while ($run)
{
connect (m$run,localhost,root,,);
connection m$run;
send;
eval UPDATE t1 SET f = CONCAT('up_',CONNECTION_ID()) WHERE i = $run;
connection master;
dec $run;
}
connection master;
SET GLOBAL event_scheduler = OFF;
let $run = 20;
while ($run)
{
connection m$run;
reap;
disconnect m$run;
dec $run;
}
#
# Clean up
#
connection slave;
source include/stop_slave.inc;
disable_warnings;
UNINSTALL PLUGIN rpl_semi_sync_slave;
connection master;
UNINSTALL PLUGIN rpl_semi_sync_master;
enable_warnings;
connection slave;
source include/start_slave.inc;
connection master;
DROP EVENT ev1;
DROP EVENT ev2;
DROP TABLE t1;
sync_slave_with_master;
plugin/semisync/semisync_master.cc
View file @ c926610d
......@@ -63,29 +63,14 @@ static int gettimeofday(struct timeval *tv, void *tz)
*
******************************************************************************/
ActiveTranx::ActiveTranx(int max_connections,
pthread_mutex_t *lock,
ActiveTranx::ActiveTranx(pthread_mutex_t *lock,
unsigned long trace_level)
: Trace(trace_level), num_transactions_(max_connections),
num_entries_(max_connections << 1),
: Trace(trace_level),
num_entries_(max_connections << 1), /* Transaction hash table size
* is set to double the size
* of max_connections */
lock_(lock)
{
/* Allocate the memory for the array */
node_array_ = new TranxNode[num_transactions_];
for (int idx = 0; idx < num_transactions_; ++idx)
{
node_array_[idx].log_pos_ = 0;
node_array_[idx].hash_next_ = NULL;
node_array_[idx].next_ = node_array_ + idx + 1;
node_array_[idx].log_name_ = new char[FN_REFLEN];
node_array_[idx].log_name_[0] = '\x0';
}
node_array_[num_transactions_-1].next_ = NULL;
/* All nodes in the array go to the pool initially. */
free_pool_ = node_array_;
/* No transactions are in the list initially. */
trx_front_ = NULL;
trx_rear_ = NULL;
......@@ -95,24 +80,13 @@ ActiveTranx::ActiveTranx(int max_connections,
for (int idx = 0; idx < num_entries_; ++idx)
trx_htb_[idx] = NULL;
sql_print_information("Semi-sync replication initialized for %d "
"transactions.", num_transactions_);
sql_print_information("Semi-sync replication initialized for transactions.");
}
ActiveTranx::~ActiveTranx()
{
for (int idx = 0; idx < num_transactions_; ++idx)
{
delete [] node_array_[idx].log_name_;
node_array_[idx].log_name_ = NULL;
}
delete [] node_array_;
delete [] trx_htb_;
node_array_ = NULL;
trx_htb_ = NULL;
num_transactions_ = 0;
num_entries_ = 0;
}
......@@ -143,26 +117,21 @@ unsigned int ActiveTranx::get_hash_value(const char *log_file_name,
ActiveTranx::TranxNode* ActiveTranx::alloc_tranx_node()
{
TranxNode *ptr = free_pool_;
if (free_pool_)
{
free_pool_ = free_pool_->next_;
ptr->next_ = NULL;
ptr->hash_next_ = NULL;
}
else
MYSQL_THD thd= (MYSQL_THD)current_thd;
/* The memory allocated for TranxNode will be automatically freed at
the end of the command of current THD. And because
ha_autocommit_or_rollback() will always be called before that, so
we are sure that the node will be removed from the active list
before it get freed. */
TranxNode *trx_node = (TranxNode *)thd_alloc(thd, sizeof(TranxNode));
if (trx_node)
{
/*
free_pool should never be NULL here, because we have
max_connections number of pre-allocated nodes.
*/
sql_print_error("You have encountered a semi-sync bug (free_pool == NULL), "
"please report to http://bugs.mysql.com");
assert(free_pool_);
trx_node->log_name_[0] = '\0';
trx_node->log_pos_= 0;
trx_node->next_= 0;
trx_node->hash_next_= 0;
}
return ptr;
return trx_node;
}
int ActiveTranx::compare(const char *log_file_name1, my_off_t log_file_pos1,
......@@ -306,8 +275,6 @@ int ActiveTranx::clear_active_tranx_nodes(const char *log_file_name,
/* Clear the active transaction list. */
if (trx_front_ != NULL)
{
trx_rear_->next_ = free_pool_;
free_pool_ = trx_front_;
trx_front_ = NULL;
trx_rear_ = NULL;
}
......@@ -326,11 +293,6 @@ int ActiveTranx::clear_active_tranx_nodes(const char *log_file_name,
{
next_node = curr_node->next_;
/* Put the node in the memory pool. */
curr_node->next_ = free_pool_;
free_pool_ = curr_node;
n_frees++;
/* Remove the node from the hash table. */
unsigned int hash_val = get_hash_value(curr_node->log_name_, curr_node->log_pos_);
TranxNode **hash_ptr = &(trx_htb_[hash_val]);
......@@ -391,8 +353,7 @@ ReplSemiSyncMaster::ReplSemiSyncMaster()
wait_file_pos_(0),
master_enabled_(false),
wait_timeout_(0L),
state_(0),
max_transactions_(0L)
state_(0)
{
strcpy(reply_file_name_, "");
strcpy(wait_file_name_, "");
......@@ -413,7 +374,6 @@ int ReplSemiSyncMaster::initObject()
/* References to the parameter works after set_options(). */
setWaitTimeout(rpl_semi_sync_master_timeout);
setTraceLevel(rpl_semi_sync_master_trace_level);
max_transactions_ = (int)max_connections;
/* Mutex initialization can only be done after MY_INIT(). */
pthread_mutex_init(&LOCK_binlog_, MY_MUTEX_INIT_FAST);
......@@ -436,9 +396,7 @@ int ReplSemiSyncMaster::enableMaster()
if (!getMasterEnabled())
{
active_tranxs_ = new ActiveTranx(max_connections,
&LOCK_binlog_,
trace_level_);
active_tranxs_ = new ActiveTranx(&LOCK_binlog_, trace_level_);
if (active_tranxs_ != NULL)
{
commit_file_name_inited_ = false;
......
plugin/semisync/semisync_master.h
View file @ c926610d
......@@ -23,31 +23,26 @@
/**
This class manages memory for active transaction list.
We record each active transaction with a TranxNode. Because each
session can only have only one open transaction, the total active
transaction nodes can not exceed the maximum sessions. Currently
in MySQL, sessions are the same as connections.
We record each active transaction with a TranxNode, each session
can have only one open transaction. Because of EVENT, the total
active transaction nodes can exceed the maximum allowed
connections.
*/
class ActiveTranx
:public Trace {
private:
struct TranxNode {
char *log_name_;
char log_name_[FN_REFLEN];
my_off_t log_pos_;
struct TranxNode *next_; /* the next node in the sorted list */
struct TranxNode *hash_next_; /* the next node during hash collision */
};
/* The following data structure maintains an active transaction list. */
TranxNode *node_array_;
TranxNode *free_pool_;
/* These two record the active transaction list in sort order. */
TranxNode *trx_front_, *trx_rear_;
TranxNode **trx_htb_; /* A hash table on active transactions. */
int num_transactions_; /* maximum transactions */
int num_entries_; /* maximum hash table entries */
pthread_mutex_t *lock_; /* mutex lock */
......@@ -74,8 +69,7 @@ private:
}
public:
ActiveTranx(int max_connections, pthread_mutex_t *lock,
unsigned long trace_level);
ActiveTranx(pthread_mutex_t *lock, unsigned long trace_level);
~ActiveTranx();
/* Insert an active transaction node with the specified position.
......@@ -177,11 +171,6 @@ class ReplSemiSyncMaster
bool state_; /* whether semi-sync is switched */
/* The number of maximum active transactions. This should be the same as
* maximum connections because MySQL does not do connection sharing now.
*/
int max_transactions_;
void lock();
void unlock();
void cond_broadcast();
......
sql/rpl_handler.cc
View file @ c926610d
......@@ -137,28 +137,53 @@ void delegates_destroy()
*/
#define FOREACH_OBSERVER(r, f, thd, args) \
param.server_id= thd->server_id; \
/*
Use a struct to make sure that they are allocated adjacent, check
delete_dynamic().
*/ \
struct { \
DYNAMIC_ARRAY plugins; \
/* preallocate 8 slots */ \
plugin_ref plugins_buffer[8]; \
} s; \
DYNAMIC_ARRAY *plugins= &s.plugins; \
plugin_ref *plugins_buffer= s.plugins_buffer; \
my_init_dynamic_array2(plugins, sizeof(plugin_ref), \
plugins_buffer, 8, 8); \
read_lock(); \
Observer_info_iterator iter= observer_info_iter(); \
Observer_info *info= iter++; \
for (; info; info= iter++) \
{ \
plugin_ref plugin= \
my_plugin_lock(thd, &info->plugin); \
my_plugin_lock(0, &info->plugin); \
if (!plugin) \
{ \
r= 1; \
/* plugin is not intialized or deleted, this is not an error */ \
r= 0; \
break; \
} \
insert_dynamic(plugins, (uchar *)&plugin); \
if (((Observer *)info->observer)->f \
&& ((Observer *)info->observer)->f args) \
{ \
r= 1; \
plugin_unlock(thd, plugin); \
sql_print_error("Run function '" #f "' in plugin '%s' failed", \
info->plugin_int->name.str); \
break; \
} \
plugin_unlock(thd, plugin); \
} \
unlock()
unlock(); \
/*
Unlock plugins should be done after we released the Delegate lock
to avoid possible deadlock when this is the last user of the
plugin, and when we unlock the plugin, it will try to
deinitialize the plugin, which will try to lock the Delegate in
order to remove the observers.
*/ \
plugin_unlock_list(0, (plugin_ref*)plugins->buffer, \
plugins->elements); \
delete_dynamic(plugins)
int Trans_delegate::after_commit(THD *thd, bool all)
......
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