branches/5.1:

Merge a change from MySQL:

  ------------------------------------------------------------
  revno: 2646.161.4
  committer: Tatiana A. Nurnberg <azundris@mysql.com>
  branch nick: 51-31177v2
  timestamp: Mon 2009-01-12 06:32:49 +0100
  message:
    Bug#31177: Server variables can't be set to their current values
    
    Bounds-checks and blocksize corrections were applied to user-input,
    but constants in the server were trusted implicitly. If these values
    did not actually meet the requirements, the user could not set change
    a variable, then set it back to the (wonky) factory default or maximum
    by explicitly specifying it (SET <var>=<value> vs SET <var>=DEFAULT).
    
    Now checks also apply to the server's presets. Wonky values and maxima
    get corrected at startup. Consequently all non-offsetted values the user
    sees are valid, and users can set the variable to that exact value if
    they so desire.

handler/ha_innodb.cc

@@ -8252,7 +8252,7 @@ static MYSQL_SYSVAR_BOOL(adaptive_hash_index, innobase_adaptive_hash_index,
 static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "Size of a memory pool InnoDB uses to store data dictionary information and other internal data structures.",
-  NULL, NULL, 1*1024*1024L, 512*1024L, ~0L, 1024);
+  NULL, NULL, 1*1024*1024L, 512*1024L, LONG_MAX, 1024);
 
 static MYSQL_SYSVAR_ULONG(autoextend_increment, srv_auto_extend_increment,
   PLUGIN_VAR_RQCMDARG,
@@ -8292,7 +8292,7 @@ static MYSQL_SYSVAR_LONG(lock_wait_timeout, innobase_lock_wait_timeout,
 static MYSQL_SYSVAR_LONG(log_buffer_size, innobase_log_buffer_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "The size of the buffer which InnoDB uses to write log to the log files on disk.",
-  NULL, NULL, 1024*1024L, 256*1024L, ~0L, 1024);
+  NULL, NULL, 1024*1024L, 256*1024L, LONG_MAX, 1024);
 
 static MYSQL_SYSVAR_LONGLONG(log_file_size, innobase_log_file_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
@@ -8312,7 +8312,7 @@ static MYSQL_SYSVAR_LONG(mirrored_log_groups, innobase_mirrored_log_groups,
 static MYSQL_SYSVAR_LONG(open_files, innobase_open_files,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "How many files at the maximum InnoDB keeps open at the same time.",
-  NULL, NULL, 300L, 10L, ~0L, 0);
+  NULL, NULL, 300L, 10L, LONG_MAX, 0);
 
 static MYSQL_SYSVAR_ULONG(sync_spin_loops, srv_n_spin_wait_rounds,
   PLUGIN_VAR_RQCMDARG,