[TYPO3-core] [FEATURE] Write session data in on update-query instead of delete/insert

[Steffen Gebert]

Hi all,

https://review.typo3.org/2761
> Session data was deleted and inserted. Using update the same process
> is possible with just one query and and no possiblity of an
> inconsistent state between delete and insert (without transactions).

I just want to start discussion here. Helmut gave a very important 
comment (and I guess that's why so many are fine by reading, but nobody 
dares to give is final Verified vote, as there could be a few bad 
side-effects):

> I'm not generally against this change, but wanted to be sure that anybody who voted +1 is aware of the fact, that this change will result in an extra database query even on sites that do not make use of fe_sessions at all.
> This might be a problem on high traffic sites with many new users hitting it, because for every new user a fe_session record is stored into the database.
> When we fixed the session fixation problem back then, we agreed to avoid an additional query during the frontend rendering.
> Nevertheless the "side-effect" of this change would be that the session cookie for fe_users would stay the same, as there would be a session record stored in the db for every user (repeating myself)

I agree that we must not create additional overhead for sites, which 
don't rely on sessions (or start a session, where none is needed).

So do you (Helmut or others) see a way to save this one query, when a 
session is required?

Kind regards
Steffen

-- 
Steffen Gebert
TYPO3 v4 Core Team Member
TYPO3 Server Administration Team Member

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