Data

When it comes to SQL Query tuning with customers we often get the slow running SQL query and possibly, in good cases, also the table structure. But very often, for various reasons, we do not get the data.

SQL query tuning on an empty table or a table with only little data is not really fun because either the results of the optimizer have nothing to do with reality or the response times do not really show if your change has improved anything. For example if your query response time before the change was 2 ms …

InnoDB is known to have crash-recovery capabilities and thus is called a crash safe storage engine (in contrary to MyISAM). Nevertheless under certain circumstances it seems like InnoDB pages can get corrupt during a crash and then a manual crash-recovery is needed.

Oracle/MySQL blames in such cases the Operating System, the I/O system or the hardware. What we have seen is that such incidents occur more often on Windows systems and when people are running their databases in a virtualized environment …

Applications occasionally require redesign. However, redesigning an application cannot be done in one step because the application is distributed or several versions of applications must be supported. MySQL 5.0 provides the necessary means to stealthy migrate your data. In a short overview let’s look at what we plan to do: Stealthy Migration (PDF 98.7 kByte).