[SOLVED] Locking Tables

[coutts]

Hello:

I have read a lot about "locking" tables. Really I can't make head nor tails of this and when and how it might be used. Nearest I might be able to understand is that this would be used when multiple users might be trying to add to or modify the table. Can anyone enlighten me

[awpti]

ISAM table typles LOCK on INSERT/UPDATE/ALTERATIONS. Nature of the beast. That means no further queries can be issues against said ISAM TABLE until the process is complete.

 

This is the most common cause of sites getting deadlocked due to a huge queue of slow-running queries.

 

ISAM does Table-level locking.

InnoDB does row-level locking (Better)

Falcon (MySQL 6.0) does coordinate level locking (Bestesterester)

 

I think the new MySQL 6.0 Miriam (Replacement for ISAM) engine does row-level locking, too.

[cooldude832]

I've never used it and never had a problem.

 

If you are going to do massive updates on the server side of things I'd suggest just lockin down your whole site instead.

[coutts]

Thanks for the input:

 

As this db is ISAM and it will never be a busy site it sounds like SQL takes care of this itself well enough I dont have to bother about it

 

Thanks

Robert

[cooldude832]

If you think about it there is an extremely limited situation that causes an issue.

 

Like if an Admin is updating a product database and then someone attempts to place an order on you site the item price may be incorrect.

 

However properly written php and if needed innoDB can cover you