if you are unfamiliar with nfs sillynames, they occur when a file that is open on one client is removed or renamed on another.
i am seeing alot of these appear in an NFS directory i'm using to store a sqlite database acessed by many clients. the access protocol is a meta-transaction wrapped around an actual sqlite transaction using an additional empty lockfile (db.lock). this is to ensure single writer multiple reader semantics for the entire network, eg.
lock_type = read # or perhaps write
aquire fcntl lock of lock_type on db.lock
open db.lock
start_transaction(lock_type)
db.execute(sql)
end_transaction
close db.lock
release fcntl lock
NONE of the applications has exited for about 30 days. ALL of the application are aquiring write locks on the db.lock so one process only is accessing the db. NONE of the uses removes, renames, etc. the file - only reads and writes are done via the sqlite api. the semantics are definitely single writer (and potentially) many reader, if this we not so the application would crash horribly almost instantly. the api i'm using throws an exception if it gets SQLITE_BUSY and i have no busy handler so i am positive that the locking works, and that no readers ever attempt to write (upgrade lock) and vice versa.
i'm simply mystified as to what's creating the sillynames. they all appear to be the product of the sqlite api: opening them up in vi shows them to be a binary file that's obviously part of the database since i can recognize many strings from the database in them.
is worries me - it seems to imply that sqlite, at some point does a rename or remove when some remote client has an open file handle. could this be because ALL of my operations (even reads) is inside a transaction?
more info...
the sillynamed files are only ever a minute or so old and disappear almost as quickly (this would be after the last client called a close). the application is working great but i'd like to understand this as it concerns me somewhat. the sqlite lib version is the latest 2.8 branch. the nfs server/client impl are the latest patched redhat enterprise versions.
kind regards.
-a
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