How to reduce cache_imagesizes queries in Typo3 4.5

Question

We have an old Typo3 4.5 application running very slowly on any server. Using blackfire.io and general debugging we are trying to figure out the bottleneck and whether we can alleviate some of the processing time.

The application uses the tt_news extension on various pages on the website. The index page has a lot of different tt_news modules, displaying entries for various categories and the like. All these entries also usually have a picture associated with them.

One of the major bottlenecks is the large number of SQL queries executed by Typo3. Particularly taxing is the following query, which is executed 247 times (!) on the start page:

SELECT ... FROM cache_imagesizes WHERE md5filename = ? limit ?

So far I wasn't able to find any ressource on how to alleviate this or if it is even possible. I think that the tt_news extension is just extremely inefficient.

Any input is appreciated.

Answer 1

Please try to set an index on md5filename. As this is a hash column, an index should be not more than five characters.

247 queries means that you have 247 pictures that are taken into account in order to render the front page. If you do not display that many pictures, try to reduce the data taking into account by setting limits in the plugins and in the rendering.