[development] auto_increment

[Gerhard Killesreiter]

Nicolas Tostin wrote:

>>>Btw, due to the chaotic use of sequences table (sometime it's used,
>>>sometimes not)
>>>      
>>>
>>When not?
>>
>>    
>>
>
>I don't have an exact list, but I remember having found some examples, so I
>understood that it was better handling them by DB trigger (for Oracle schema
>I mean) than doing nothing .
>  
>

The general scheme is that we use locking if we want to know the ID in 
advance or if we need it afterwards for further processing (example: 
node iD). If we only need to make sure that we get a unique ID and don't 
care about its value we use auto_increment (examples: accesslog, 
watchdog). Using LOCK to get the IDs would be a bad idea for performance 
reasons.

Cheers,
    Gerhard