Add idx field; a always increasing experiment ID. I expect we will be

dead before it flows 32 bits.

sql/database-create.sql

@@ -202,7 +202,9 @@ CREATE TABLE experiments (
   swap_requests tinyint(4) NOT NULL default '0',
   last_swap_req datetime default NULL,
   idle_ignore tinyint(4) NOT NULL default '0',
-  PRIMARY KEY  (eid,pid)
+  idx int(10) unsigned NOT NULL auto_increment,
+  PRIMARY KEY  (eid,pid),
+  KEY idx (idx)
 ) TYPE=MyISAM;
 
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