Re: Long query locking up MySQL Server

[Radek Antoniuk]

Thanks for the hint about the redundant keys.
I didn't know that complex "sub-keys" are useful for one-column keys as well.

The other table is:

 CREATE TABLE `kody_regionow` (
  `kod` char(3) COLLATE utf8_polish_ci NOT NULL DEFAULT '',
  `region` varchar(50) COLLATE utf8_polish_ci NOT NULL DEFAULT '',
  `panstwo` varchar(80) COLLATE utf8_polish_ci NOT NULL DEFAULT '',
  `kod_panstwa_iso` char(2) COLLATE utf8_polish_ci NOT NULL,
  `kod_pogoda` varchar(10) COLLATE utf8_polish_ci NOT NULL,
  UNIQUE KEY `kod` (`kod`),
  KEY `kod_panstwa_iso` (`kod_panstwa_iso`),
  KEY `region` (`region`),
  KEY `kodyRegionyIdx` (`region`,`panstwo`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_polish_ci