bk commit into 5.0 tree (petr:1.2065)

[Petr Chardin]

Below is the list of changes that have just been committed into a local
5.0 repository of cps. When cps does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2065 06/02/21 15:59:41 petr@stripped +1 -0
  Merge pchardin@stripped:/home/bk/mysql-5.0
  into  mysql.com:/home/cps/mysql/devel/im/5.0-im-fix-race

  server-tools/instance-manager/instance_map.cc
    1.26 06/02/21 15:59:35 petr@stripped +0 -0
    Auto merged

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	petr
# Host:	outpost.site
# Root:	/home/cps/mysql/devel/im/5.0-im-fix-race/RESYNC

--- 1.25/server-tools/instance-manager/instance_map.cc	2006-02-10 02:15:52 +03:00
+++ 1.26/server-tools/instance-manager/instance_map.cc	2006-02-21 15:59:35 +03:00
@@ -80,19 +80,44 @@
 static int process_option(void *ctx, const char *group, const char *option)
 {
   Instance_map *map= NULL;
+
+  map = (Instance_map*) ctx;
+  return map->process_one_option(group, option);
+}
+
+C_MODE_END
+
+
+/*
+  Process one option from the configuration file.
+
+  SYNOPSIS
+    Instance_map::process_one_option()
+      group         group name
+      option        option string (e.g. "--name=value")
+
+  DESCRIPTION
+    This is an auxiliary function and should not be used externally.
+    It is used only by flush_instances(), which pass it to
+    process_option(). The caller ensures proper locking
+    of the instance map object.
+*/
+
+int Instance_map::process_one_option(const char *group, const char *option)
+{
   Instance *instance= NULL;
   static const char prefix[]= { 'm', 'y', 's', 'q', 'l', 'd' };
 
-  map = (Instance_map*) ctx;
   if (strncmp(group, prefix, sizeof prefix) == 0 &&
       ((my_isdigit(default_charset_info, group[sizeof prefix]))
        || group[sizeof(prefix)] == '\0'))
     {
-      if ((instance= map->find(group, strlen(group))) == NULL)
+      if (!(instance= (Instance *) hash_search(&hash, (byte *) group,
+                                               strlen(group))))
       {
-        if ((instance= new Instance) == 0)
+        if (!(instance= new Instance))
           goto err;
-        if (instance->init(group) || map->add_instance(instance))
+        if (instance->init(group) || my_hash_insert(&hash, (byte *) instance))
           goto err_instance;
       }
 
@@ -108,8 +133,6 @@
   return 1;
 }
 
-C_MODE_END
-
 
 Instance_map::Instance_map(const char *default_mysqld_path_arg):
 mysqld_path(default_mysqld_path_arg)
@@ -144,30 +167,61 @@
   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.
+
+  TODO
+    FLUSH INSTANCES should return an error if it's called
+    while there is a running instance.
+*/
 
 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.
+  */
   guardian->lock();
   pthread_mutex_lock(&LOCK_instance_map);
   hash_free(&hash);
   hash_init(&hash, default_charset_info, START_HASH_SIZE, 0, 0,
             get_instance_key, delete_instance, 0);
-  pthread_mutex_unlock(&LOCK_instance_map);
   rc= load();
   guardian->init();
+  pthread_mutex_unlock(&LOCK_instance_map);
   guardian->unlock();
   return rc;
 }
 
 
-int Instance_map::add_instance(Instance *instance)
-{
-  return my_hash_insert(&hash, (byte *) instance);
-}
-
-
 Instance *
 Instance_map::find(const char *name, uint name_len)
 {
@@ -190,9 +244,8 @@
     if ((instance= new Instance) == 0)
       goto err;
 
-    if (instance->init("mysqld") || add_instance(instance))
+    if (instance->init("mysqld") || my_hash_insert(&hash, (byte *) instance))
       goto err_instance;
-
 
     /*
       After an instance have been added to the instance_map,