I've upgraded from 3.5.8 to 4.0.0 and now if I try to import a gzipped export file that i created from another PMA installation, I get a 504 Gateway Timeout even though the file is very small. If i downgrade to 3.5.8 again, the same file is importet in less than 5 s.
I've tested in both, Chrome and Firefox. The MySQL version is 5.5.31-0ubuntu0.12.10.1-log - (Ubuntu).
The only log output is:
2013/05/11 10:40:11 [error] 13561#0: 34069 upstream timed out (110: Connection timed out) while reading response header from upstream, client: ...7, server: ssl..de, request: "GET /pma/import_status.php?message=true&token=HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "ssl..de", referrer: "https://ssl..de/pma/index.php?token=***"