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Fix for the following bugs:

Browse Source 
- BUG#22306: STOP INSTANCE can not be applied for instances in Crashed,
    Failed and Abandoned;
  - BUG#23476: DROP INSTANCE does not work
  - BUG#23215: STOP INSTANCE takes too much time

BUG#22306:
The problem was that STOP INSTANCE checked that mysqld is up and running.
If it was not so, STOP INSTANCE reported an error. Now, STOP INSTANCE
reports an error if the instance has been started (mysqld can be down).

BUG#23476:
The problem was that DROP INSTANCE tried to stop inactive instance. The fix is
trivial.

BUG#23215:
The problem was that locks were not acquired properly, so the
instance-monitoring thread could not acquire the mutex, holded by the
query-processing thread.

The fix is to simplify locking scheme by moving instance-related information to
Instance-class out of Guardian-class. This allows to get rid of storing a
separate list of Instance-information in Guardian and keeping it synchronized
with the original list in Instance_map.
This commit is contained in:
anozdrin/alik@booka.
2006-11-30 12:23:55 +03:00
parent 931cf68b59
commit b534ca4bc0
12 changed files with 1398 additions and 986 deletions
Download Patch File Download Diff File Expand all files Collapse all files

217
server-tools/instance-manager/instance_map.cc
View File

@ -25,26 +25,18 @@
#include <mysql_com.h>
#include "buffer.h"
#include "guardian.h"
#include "instance.h"
#include "log.h"
#include "manager.h"
#include "mysqld_error.h"
#include "mysql_manager_error.h"
#include "options.h"
#include "priv.h"
/*
Note: As we are going to suppost different types of connections,
we shouldn't have connection-specific functions. To avoid it we could
put such functions to the Command-derived class instead.
The command could be easily constructed for a specific connection if
we would provide a special factory for each connection.
*/
C_MODE_START
/* Procedure needed for HASH initialization */
/**
HASH-routines: get key of instance for storing in hash.
*/
static byte* get_instance_key(const byte* u, uint* len,
my_bool __attribute__((unused)) t)
@ -54,14 +46,18 @@ static byte* get_instance_key(const byte* u, uint* len,
return (byte *) instance->options.instance_name.str;
}
/**
HASH-routines: cleanup handler.
*/
static void delete_instance(void *u)
{
Instance *instance= (Instance *) u;
delete instance;
}
/*
The option handler to pass to the process_default_option_files finction.
/**
The option handler to pass to the process_default_option_files function.
SYNOPSIS
process_option()
@ -96,8 +92,8 @@ static int process_option(void *ctx, const char *group, const char *option)
C_MODE_END
/*
Parse option string.
/**
Parse option string.
SYNOPSIS
parse_option()
@ -137,7 +133,7 @@ static void parse_option(const char *option_str,
}
/*
/**
Process one option from the configuration file.
SYNOPSIS
@ -151,6 +147,10 @@ static void parse_option(const char *option_str,
process_option(). The caller ensures proper locking
of the instance map object.
*/
/*
Process a given option and assign it to appropricate instance. This is
required for the option handler, passed to my_search_option_files().
*/
int Instance_map::process_one_option(const LEX_STRING *group,
const char *option)
@ -213,92 +213,97 @@ int Instance_map::process_one_option(const LEX_STRING *group,
}
/**
Instance_map constructor.
*/
Instance_map::Instance_map()
{
pthread_mutex_init(&LOCK_instance_map, 0);
}
/**
Initialize Instance_map internals.
*/
bool Instance_map::init()
{
return hash_init(&hash, default_charset_info, START_HASH_SIZE, 0, 0,
get_instance_key, delete_instance, 0);
}
/**
Reset Instance_map data.
*/
bool Instance_map::reset()
{
hash_free(&hash);
return init();
}
/**
Instance_map destructor.
*/
Instance_map::~Instance_map()
{
pthread_mutex_lock(&LOCK_instance_map);
lock();
/*
NOTE: it's necessary to synchronize on each instance before removal,
because Instance-monitoring thread can be still alive an hold the mutex
(because it is detached and we have no control over it).
*/
while (true)
{
Iterator it(this);
Instance *instance= it.next();
if (!instance)
break;
instance->lock();
instance->unlock();
remove_instance(instance);
}
hash_free(&hash);
pthread_mutex_unlock(&LOCK_instance_map);
unlock();
pthread_mutex_destroy(&LOCK_instance_map);
}
/**
Lock Instance_map.
*/
void Instance_map::lock()
{
pthread_mutex_lock(&LOCK_instance_map);
}
/**
Unlock Instance_map.
*/
void Instance_map::unlock()
{
pthread_mutex_unlock(&LOCK_instance_map);
}
/*
Re-read instance configuration file.
SYNOPSIS
Instance_map::flush_instances()
DESCRIPTION
This function will:
- clear the current list of instances. This removes both
running and stopped instances.
- load a new instance configuration from the file.
- pass on the new map to the guardian thread: it will start
all instances that are marked `guarded' and not yet started.
Note, as the check whether an instance is started is currently
very simple (returns TRUE if there is a MySQL server running
at the given port), this function has some peculiar
side-effects:
* if the port number of a running instance was changed, the
old instance is forgotten, even if it was running. The new
instance will be started at the new port.
* if the configuration was changed in a way that two
instances swapped their port numbers, the guardian thread
will not notice that and simply report that both instances
are configured successfully and running.
In order to avoid such side effects one should never call
FLUSH INSTANCES without prior stop of all running instances.
NOTE: The operation should be invoked with the following locks acquired:
- Guardian;
- Instance_map;
/**
Check if there is an active instance or not.
*/
int Instance_map::flush_instances()
{
int rc;
/*
Guardian thread relies on the instance map repository for guarding
instances. This is why refreshing instance map, we need (1) to stop
guardian (2) reload the instance map (3) reinitialize the guardian
with new instances.
*/
hash_free(&hash);
hash_init(&hash, default_charset_info, START_HASH_SIZE, 0, 0,
get_instance_key, delete_instance, 0);
rc= load();
/* don't init guardian if we failed to load instances */
if (!rc)
guardian->init(); // TODO: check error status.
return rc;
}
bool Instance_map::is_there_active_instance()
{
Instance *instance;
@ -306,29 +311,50 @@ bool Instance_map::is_there_active_instance()
while ((instance= iterator.next()))
{
if (guardian->find_instance_node(instance) != NULL ||
instance->is_mysqld_running())
{
bool active_instance_found;
instance->lock();
active_instance_found= instance->is_active();
instance->unlock();
if (active_instance_found)
return TRUE;
}
}
return FALSE;
}
/**
Add an instance into the internal hash.
MT-NOTE: Instance Map must be locked before calling the operation.
*/
int Instance_map::add_instance(Instance *instance)
{
return my_hash_insert(&hash, (byte *) instance);
}
/**
Remove instance from the internal hash.
MT-NOTE: Instance Map must be locked before calling the operation.
*/
int Instance_map::remove_instance(Instance *instance)
{
return hash_delete(&hash, (byte *) instance);
}
/**
Create a new instance and register it in the internal hash.
MT-NOTE: Instance Map must be locked before calling the operation.
*/
int Instance_map::create_instance(const LEX_STRING *instance_name,
const Named_value_arr *options)
{
@ -392,12 +418,22 @@ int Instance_map::create_instance(const LEX_STRING *instance_name,
}
/**
Return a pointer to the instance or NULL, if there is no such instance.
MT-NOTE: Instance Map must be locked before calling the operation.
*/
Instance * Instance_map::find(const LEX_STRING *name)
{
return (Instance *) hash_search(&hash, (byte *) name->str, name->length);
}
/**
Init instances command line arguments after all options have been loaded.
*/
bool Instance_map::complete_initialization()
{
bool mysqld_found;
@ -455,7 +491,10 @@ bool Instance_map::complete_initialization()
}
/* load options from config files and create appropriate instance structures */
/**
Load options from config files and create appropriate instance
structures.
*/
int Instance_map::load()
{
@ -505,8 +544,9 @@ int Instance_map::load()
}
/*--- Implementaton of the Instance map iterator class ---*/
/*************************************************************************
{{{ Instance_map::Iterator implementation.
*************************************************************************/
void Instance_map::Iterator::go_to_first()
{
@ -522,29 +562,12 @@ Instance *Instance_map::Iterator::next()
return NULL;
}
const char *Instance_map::get_instance_state_name(Instance *instance)
{
LIST *instance_node;
if (!instance->is_configured())
return "misconfigured";
if ((instance_node= guardian->find_instance_node(instance)) != NULL)
{
/* The instance is managed by Guardian: we can report precise state. */
return Guardian::get_instance_state_name(
guardian->get_instance_state(instance_node));
}
/* The instance is not managed by Guardian: we can report status only. */
return instance->is_mysqld_running() ? "online" : "offline";
}
/*************************************************************************
}}}
*************************************************************************/
/*
/**
Create a new configuration section for mysqld-instance in the config file.
SYNOPSIS