[TYPO3-v4] Current master branch is broken?

[Christian Kuhn]

Hey,

On 06/28/2011 04:09 PM, Ernesto Baschny [cron IT] wrote:
> I have no clue about this specific problem, and have not followed the
> caching framework latest development

Some explanations to the whole thing:
The cf db backend had the problem that if extensions define own caches 
with this backend they had to add the needed table structure to their 
ext_tables.sql for the tables (data + tags). This made it effectively 
impossible for core to change the layout of the table structure because 
extensions had to catch up with this. So we had a dependency from core 
to extensions, which is bad.

Therefore recent db backend changes did the following:
- Table definition is handled by the backend itself (there are template 
sql files).
- Table names are constructed from the (unique) cache name and prefixed 
with 'cachingframework_'.
- If flushing a cache with db backend, additional to the 'truncate' the 
tables are dropped and created with defined layout again. (=> zero 
overhead in production).
- The install tool db analyzer was changed to ignore all tables that are 
prefixed with 'cachingframework_'

So, in effect, the db backend now takes care of needed db structure on 
its own. This allows us to change the structure however we need without 
any dependencies to extensions (and extensions do not need to declare 
table structure and naming things).

I thought that flush() would do the trick (because on upgrading usually 
every user flushes caches at least once), but looking at Dmitry's login 
issue it might be better to just check with mysql_error() at more place 
and upgrade table definition silently if some query failed (I'll think 
about this a bit and will come up with a patch if it turns out to be a 
clever solution).

So thanks for your report Dmitry, I was unaware that the 'update tables 
on flush()' method could fail because a login is impossible. Anyway, a 
simple upgrade wizard that just calls cacheManager->flushCaches() and 
deletes temp_CACHED* should be created, too.


Regards
Christian