Subject Re: atomicity of UPDATEs
Author hvlad
> Under 2.1.3, the following statement...
> UPDATE tbl SET q = q + 1, p = q;
> appears non-atomic to me, seeing two different values for "Q" while
> updating a single row.

It is fixed at v2.5. Search in its ReleaseNotes for "Logic Change in SET Clause".