Re: file locking...

2009/3/1 Robert Cummings <robert@interjinn.com> > On Sun, 2009-03-01 at 10:05 -0800, bruce wrote: > > hi rob... > > > > what you have written is similar to my initial approach... my question, > and > > the reason for posting this to a few different groups.. is to see if > someone > > has pointers/thoughts for something much quicker... > > > > this is going to handle processing requests from client apps to a > > webservice.. the backend of the service has to quickly process the files > in > > the dir as fast as possible to return the data to the web client query... > > Then use a database to process who gets what. DB queries will queue up > while a lock is in place so batches will occur on first come first > served basis. I had thought this was for a background script. This will > save your script from having to browse the filesystem files, sort by > age, etc. Instead put an index on the ID of the file and grab the X > lowest IDs. A database would be the best way to do this, but I've need to handle this situation with files in the past and this is the solution I came up with... 1) Get the next filename to process 2) Try to move it to /tmp/whatever.<pid> 3) Check to see if /tmp/whatever.<pid> exists, and if it does process it then delete it or move it to an archive directory 4) Repeat until there are no files left to process I have this running on a server that processes several million files a day without any issues. For database-based queues I use a similar system but the move is replaced by an update which sets the pid field of a single row. I then do a select where that pid is my pid and process whatever comes back. I have several queues that use this system and combined they're handling 10's of millions of queue items per day without any problems, with the advantage that I can scale across servers as well as processes. -Stuart -- http://stut.net/