[Typo3-dev] cache tables (was: Re: Empty cHash problem)

[Ernesto Baschny [cron IT]]

Elmar Hinz schrieb am 07.10.2005 11:25:

>>> By the way. Is there a special table for caching views with additional
>>> parameters or is it the same table as for the old id + type combination?
>>> Which tables are they? Wich fields in the tables?

>> Its the same table, as the cache already uses different combination of
>> parameters for caching the same page (e.g for different types). The
>> table is cache_pages, the content is in the HTML field. You will have a
>> huge configuration array in cache_data, which unserialized will also
>> tell you (amongst other) the piVar-parameters that were used to create
>> this cache request. But what TYPO3 uses to see which record to get is
>> the md5-hash of a series of information (fe_group, parameters, type,
>> language, etc), which will be compared against the "hash" field.

> Thank you very much. We find some other cache tables:
> 
> cache_pages : Our cached content

> cache_hash  : ???

I would call cache_hash as a "general purpose cache table". You can
store anything inside it, and retrieve it later by its md5-hash value.
Its used by the core to cache parsed TypoScript, parsed menu structures,
etc. See t3lib_pageSelect::getHash() and t3lib_pageSelect::storeHash()
to use them on your own.

> cache_imagesizes: caches imagesizes, so they don't need to be remeasured
> for html output

> cache_md5params: ???

As far as I understood it, its used by SimulateStatic for caching the
the parameters of an URL. The md5 is calculated and this is then used by
SimulateStatic in the URL instead. TYPO3 retrieves the parameters back
from this table when the URL is called.

> cache_pagesection: ???

Again, as far as I understood: This caches the conditions that might
influence the output for each page-id in the typoscript template. This
way TYPO3 core will be able to just apply the relevant condition checks,
and skip the ones that aren't relevant for this specific page (e.g.
browser-check for pages that do not have any browser-related condition
in its TypoScript).


Cheers,
Ernesto