[TYPO3-core] RFC #12800: Add functionality to work with caching framework [DBAL]

[Oliver Hader]

FYI: Committed to SVN Trunk (rev. 6589)

after my +1 by reading and testing

olly


Xavier Perseguers schrieb:
> Hi,
> 
> This is an SVN patch request.
> 
> Type: Bugfix / cleanup for DBAL
> 
> Bugtracker reference:
> http://bugs.typo3.org/view.php?id=12800
> 
> Branch: Trunk
> 
> Problem:
> DBAL currently misses functionalities to work properly with the caching
> framework. Besides that maybe also some changes in the caching framework
> are required.
> 
> Additional information:
> New caching framework uses subqueries to efficiently delete caching
> entries in database. However subqueries were not supported by DBAL. The
> DBAL part of the patch (available on the bugtracker) takes care of this.
> 
> Enclosed is the Core-related patch only.
> 
> Analysis of why (minor) changes in Core are required:
> 
> t3lib_sqlparser:
> DBAL reuses all existing parsing method for standard queries to parse
> subqueries (after all, that the same...). However, sql parser in Core
> lacks a way to give back to the caller the state of the parsedString
> after the parsing occurred. This is however a must for DBAL in order to
> resume parsing of the main query once the subquery has been parsed.
> 
> Changes in parsing framework:
> 
> New caching framework basically does this:
> 
> $GLOBALS['TYPO3_DB']->execDELETEquery(
>     'cachingframework_cache_hash_tags',
>     'identifier IN (' .
>         $GLOBALS['TYPO3_DB']->SELECTquery(
>             'identifier',
>             'cachingframework_cache_pages',
>             'crdate + lifetime < ' . time() . ' AND lifetime > 0'
>         ) .
>     ')'
> );
> 
> Problem is that this creates a SELECT statement that is already quoted
> (when using PostgreSQL or Oracle) and puts this into a DELETE statement
> which is not yet quoted. This seems to be a good way to generate a
> SUBQUERY but actually leads to something that is not consistent for
> parsing.
> 
> Best method to prevent quoting of the subquery to let it work with DBAL
> is to add a new method to t3lib_db that aims at creating subqueries (I
> called it method SELECTsubquery) which won't be overriden by DBAL (no
> need) and that will only allow what is needed in a subquery, namely a
> list of fields, from tables and where clauses as parameters.
> 
> 
> 
> How to test:
> Patch your core, you don't need DBAL, and make sure new caching
> framework still works as expected. You'll see from patch that changes do
> not impact Core itself, but allow DBAL to handle queries of new caching
> framework.
> 
> I added unit tests in DBAL (present in patch for DBAL) to make sure new
> caching framework queries are properly parsed.
> 
> 
> Cheers
-- 
Oliver Hader
TYPO3 Release Manager 4.3
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