Here a log part :
Apr 09 16:47:46 [Mon Apr 09 16:47:46.427841 2018] [:error] [pid 748] [client 172.18.0.1:48502] PHP Fatal error: Uncaught Doctrine\DBAL\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE  FATAL: remaining connection slots are reserved for non-replication superuser connections in /app/code/lib/private/DB/Connection.php:64\nStack trace:\n#0 /app/code/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\DB\Connection->connect()\n#1 /app/code/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\DBAL\Connection->getDatabasePlatformVersion()\n#2 /app/code/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\DBAL\Connection->detectDatabasePlatform()\n#3 /app/code/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\DBAL\Connection->getDatabasePlatform()\n#4 /app/code/lib/private/DB/Connection.php(151): Doctrine\DBAL\Connection->setTransactionIsolation(2)\n#5 /app/code/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\DB\Connection->__construct(Array, Object(Doctrine\DBAL\Driver\PDOPgSql\Driver), Objec in /app/code/lib/private/DB/Connection.php on line 64
I guess this is coming from PostgreSQL since that is what the next cloud app uses. There is no rate limit in IPTables but there is a max_connection setting of 100. Strange that nextcloud is hitting such a high limit but I am guessing it is some bug in the importer.
There is a suggestion at https://productforums.google.com/forum/?hl=en#!category-topic/calendar/calendar-not-loading/EqOUPboHrmU on how to break up iCal file into smaller parts and import them one by one. @saglagla maybe you can try that?
@girish I have a 238 ko iCal file.
I've split it in twice and I went from 250 importation err from 1 err.
The problem should come from that, thanks!
I was at the beginning thinking about it (splitting the file) but after that, I was focusing on RateLimit - wrong way! Also, I advise people which want to import a big file to increase drastically the mem allowance of the app (2Gb in my case)