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Using the UPDATE WHERE statement you described is referred to as optimistic
locking. [1]

https://docs.jboss.org/jbossas/docs/Server_Configuration_Guide/4/html/The_CMP_Engine-Optimistic_Locking.html


On Wed, Jul 30, 2014 at 10:30 AM, Jay Pipes <jaypipes at gmail.com> wrote:

> On 07/30/2014 10:05 AM, Kevin Benton wrote:
>
>> i.e. 'optimistic locking' as opposed to the 'pessimistic locking'
>> referenced in the 3rd link of the email starting the thread.
>>
>
> No, there's no locking.
>
>  On Wed, Jul 30, 2014 at 9:55 AM, Jay Pipes <jaypipes at gmail.com
>> <mailto:jaypipes at gmail.com>> wrote:
>>
>>     On 07/30/2014 09:48 AM, Doug Wiegley wrote:
>>
>>             I'd have to look at the Neutron code, but I suspect that a
>>             simple
>>             strategy of issuing the UPDATE SQL statement with a WHERE
>>             condition that
>>
>>
>>         I¹m assuming the locking is for serializing code, whereas for
>>         what you
>>         describe above, is there some reason we wouldn¹t just use a
>>         transaction?
>>
>>
>>     Because you can't do a transaction from two different threads...
>>
>>     The compare and update strategy is for avoiding the use of SELECT
>>     FOR UPDATE.
>>
>>     Best,
>>     -jay
>>
>>
>>
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>>
>>
>>
>>
>> --
>> Kevin Benton
>>
>>
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>
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-- 
Kevin Benton
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