Search Results for: reverse

A recovery trivia or how to recover from a lost ibdata1 file

A few day ago, a customer came to Percona needing to recover data. Basically, while doing a transfer from one SAN to another, something went wrong and they lost the ibdata1 file, where all the table meta-data is stored. Fortunately, they were running with innodb_file_per_table so the data itself was available. What they could provide […]

MySQL Error control changes

In MySQL 5.0 mainly error control was improved, such as strict mode was added to change famous MySQL behavior of cutting too large strings, too big numbers and allowing you to use dates such as February 31st. In one case however reverse change was done – in regards to storage engine initialization. Previously if you […]

Why Index could refuse to work ?

Have you ever seen index which refused to be used even if there is every reason for it to work (from the glance view):

Why on the earth index would not be used you would think, even if MySQL is mentioning it in “possible keys” ? Should you try to force it ?

Handling big result sets

Sometime it is needed to handle a lot of rows on client side. Usual way is send query via mysql_query and than handle the result in loop mysql_fetch_array (here I use PHP functions but they are common or similar for all APIs, including C). Consider table: