[Dovecot] expire plugin: columns not uniq

[Nikita Koshikov]

No, in general.

> If one wants some data in a DB, but update if already present.
>
> If you re-programm the TRIGGER in the client, you need to lock the whole
> table, if you want to overcome all race conditions and also don't want any
> errors logged (at least with postgres).
>

Thanks for explanation.
I'm not so aware in databases, but if trigger will be programmed on client
side - this will make code more portable(in case of database choicing) and
what is the less evil -  locking or portability...
In any case, thanks for reply, it helps me much.