" certain rows can no longer be found " -- Do CHECK TABLE. (It will take a loooong time.) It may tell you to REPAIR TABLE, which will also take a loooong time; but it will be necessary. (This is a strong reason for going to InnoDB. But it will be 2x-3x bigger on disk.)
> -----Original Message----- > From: Dolan Antenucci [mailto:antenucc...@gmail.com] > Sent: Monday, August 12, 2013 10:26 AM > To: mysql@lists.mysql.com > Subject: MyISAM index missing rows > > Hi Everyone, > > I have a MyISAM table with 25 billion rows (structure: <id1 int, id2 int, > score float>), and after I create an index on id1, certain rows can no > longer be found. > > I've posted a detailed summary of my problem at dba.stackexchange.com, but > haven't had success with finding a solution thus far. Here's the URL to > that post: > http://dba.stackexchange.com/questions/47906/mysql-myisam-index-causes- > query-to-match-no-rows-indexes-disabled-rows-match > > As that post describes, one oddity is with an EXPLAIN I run on the same > query with indexes enabled vs. disabled. When disabled, "rows" = 25 > billion; when enabled, "rows" = 170 million. Based on this, I'm wondering > if some restriction is causing only 170 million rows to index. (Of course, > I could be completely misinterpreting this EXPLAIN result). > > Here is my server version: 5.5.31-0ubuntu0.12.04.2 (Ubuntu), which should > also be 64-bit (i've verified by running "file /usr/sbin/mysqld" (says > "ELF > 64 bit..") > > Any help is greatly appreciated! Just let me know if you need more > details > > Sincerely, > > Dolan Antenucci -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
