Same issue here:
Fatal error: Allowed memory size of 2097152 bytes exhausted (tried to allocate 438272 bytes) in /var/www/html/3rdparty/composer/autoload_real.php on line 37
Tried to add missing db indices with “occ db:add-missing-indices”. I’m using docker version (https://github.com/nextcloud/docker/blob/master/.examples/dockerfiles/full/apache/Dockerfile).
Running occ without any parameters gives the same result.