RE: General Implementation Questions

[Paul DuBois]

At 10:14 AM -0600 1999-12-21, Chris Means wrote:
>  > No, in any version of MySQL only one update can happen in one moment
>>  on one table. Almost like Newton ;O)
>
>OK.  One UPDATE (INSERT/DELETE ?) at a time...but can someone else be doing
>a SELECT at the same time?  I thought MySQL would use multiple CPUs if
>available, so that to me implied "more than one operation at the same
>time..."


An UPDATE involves a write lock, which locks out all other writers and
readers.  This includes SELECT operations.  Recent work allows INSERT
operations to be done during SELECT operations, but that does not yet
apply to UPDATE or DELETE.

-- 
Paul DuBois, paul@stripped