Question

I have a table with 3 million rows and 6 columns. The problem is that my mysqld server wouldn’t generate the output for any query and it would simply time out.

I then read here that over-indexing could involve too much of swapping data from memory to disk and can cause the server to slow down.

So I ran a query ALTER TABLE <Tbl_name> DROP INDEX <Index_name>;. This query has been running for 10 hours and has not completed yet.

1. Is this expected to run for so long?
2. Is there a better way to Dropping/Altering my indices?

edit – Added SHOW CREATE TABLE output

| Sample | CREATE TABLE `sample` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `FiMD5` varchar(32) NOT NULL,
  `NoMD5` varchar(32) NOT NULL,
  `SeMD5` varchar(32) NOT NULL,
  `SeesMD5` varchar(32) NOT NULL,
  `ImMD5` varchar(32) NOT NULL,
  `Ovlay` tinyint(1) NOT NULL DEFAULT '1',
  PRIMARY KEY (`ID`),
  KEY `FiMD5_3` (`FiMD5`),
  KEY `ID` (`ID`),
  KEY `ID_2` (`ID`),
  KEY `pIndex` (`FiMD5`),
  KEY `FiMD5_` (`FiMD5`,`NoMD5`)
) ENGINE=InnoDB AUTO_INCREMENT=3073630 DEFAULT CHARSET=latin1 |

Answer 1

Perhaps do the following would be faster:

1. SELECT ... INTO OUTFILE first
2. Use TRUNCATE TABLE to delete everything
3. Modify the table
4. Use LOAD to restore the data

If step 2 takes too long, perhaps dropping the table and recreate it.