File descriptors are being left open

Over the course of several days on a production server, we observed a steady increase in the number of open file descriptors associated with the node-solid-server process, until it reached the per-process limit, at which point node-solid-server stopped accepting new requests and needed to be restarted.

A few key points to note:

The vast majority of open descriptors are of type REG (regular file), with 93% of those being the profile card file. For example:

node    20481 root  305r      REG              259,1     2406   267569 /var/solid/justin.inrupt.net/profile/card

It's important to note that they were not all profile/card. For example, there are also instances of others, such as:

• settings/prefs.ttl
• RandomChat/index.ttl
• public/friends/person/uuid/index.ttl
• profile/photograph.png
• favicon.ico
• public/Dokieli/index.html
• pubilc/test.txt

So while MOST of them were rdf files, not all of them were.

Descriptors associated with a given resource are not re-used when that resource is requested again.
For example, there were 26 open descriptors for /var/solid/justin.inrupt.net/profile/card.