[TYPO3-mvc] multiple Queries for same object and queries for empty Relations

[Jonas Götze]

Hi all,

I currently have a big performance issue with an extbase extension.
I hope I have not overlooked any existing bug reports or posts related 
to this - If you know something I could not find I would be glad about a 
hint.

I have a record with a 1-to-1 relation to fe_users (Type 
Tx_Extbase_Domain_Model_FrontendUser). The property frontendUser of my 
Record is optional.
If all the Main records are fetched there is a sql Query for every 
frontendUser Property assigned to it.
2 Problems occur:
- if there is no relation at all (means 0 in the database) there will be 
a query like 'where fe_users.uid IN('0') (one per main Record) - 
obviously there will never be result for this.
- if there is a valid relation there will be a query for every single 
main Record again - though the data was fetched already multiple times 
if the relation points to the same User again and again.

While this is not a huge problem with not so many records, it becomes a 
performance problem with (only!) some hundred records (~270 in my case). 
The relations point to ~5 different Users overall actually but there are 
hundreds of queries. Furthermore this also happens for relations to 
other tables, fe_users is just my example here.
All in all I have some thousand queries with a single plugin.

To reproduce this I created a simple example Extension (created with 
extension_builder on a plain TYPO3 v6.1.6 with small adjustments 
afterwards) which you can download [1] if interested. Tested also on 
current git master of TYPO3 v6.2.

Install:
- install the extension in EM
- include static template
- create at least 1 Frontenduser with type 
"Tx_Extbase_Domain_Model_FrontendUser"
- include plugin to a page of our choice
- set storagePid (or pages in Flexforms) to be able to find the user-Record
- enable sql Debug in Install tool to see the Queries

In the Frontend you can create multiple records - either with a relation 
to your FrontendUser or without. The SQL Debug will show as much queries 
to fe_users as there are "Report"-Records anyhow.

I found this bug entry which might be related, but latest 6.2 from git 
still has the same behaviour:
http://forge.typo3.org/issues/53514

I think this is a bug, but I just wanted to be sure I have not 
overlooked something and maybe there are a few persons who can confirm 
the Problem too.

The Problem occurs since about 2months. Earlier everything was fine - 
the only things I am aware of that might have changed are the number of 
records and the TYPO3 version.

Thanks a lot for your hints/questions/suggestions/notes/...!

Best Regards
Jonas

[1] https://www.dropbox.com/s/ks1vaoisnb2nhe0/debugme_0.0.1.zip