[TYPO3-performance] 4.7 to 6.2 slow down

[Valeria Tabolsky]

Hi dear community,

we are migrating our portal that now runs on Typo3 v. 4.7 to the newest version 6.2.
And I noticed that pages don't open immediately as it was before. It takes about 2 sec of delay  and even more (depends of how the page is filled with content). But even the empty page doesn't appear at once but takes some annoying delay.

I noticed that using standard repository actions to retrieve DB entities Repository->findAll()   awfully slows down the system so I managed to use direct SQL selects:

$result = $GLOBALS['TYPO3_DB']->sql_query($query);

For example, in my local environment, to retrieve  1000 of records takes  15 sec  using findAll()  and 5 sec using plain SQL. Obviously including the page rendering, template parsing etc.

Is it a known issue of new version? Should we expect the reduction of performance after migration or it's just a configuration problem?
I suppose that by default Typo3 has complete features set that I hardly will use at all, but loading them takes time. 

May be there is a way do switch off some extra functionality and increase the speed ?

Thank you