Update speed

[Mark Modrall]

Hi...

I've got a process that selects rows from a MyISAM table for update. The updates are really small - updating 2 1-byte flag fields. It's written in C# using the .Net connector to a remote server.

I have one connection executing the select/Read() and another connection executing the update command (i had trouble using a connection with an active reader for other purposes). Anyway, as it stands, updating 1.4M rows is taking about 40 minutes, which seems like a long time given that it's only flipping a couple of bits. Neither of the changed bytes are part of an index that would need updating.

I've tried using UPDATE LOW_PRIORITY but that doesn't seem to improve performance appreciably.

I'm figuring a big chunk of the update time is due to it having no context and it having to go look up the record again on the primary index.

Is there any way to improve the performance of a select/update operation since you know every record selected needs an update?

Thanks
_mark