2003-09-11T13:56:50 shantanu: > Just out of curiouslity how much time did it take and did anyone else > have this problem. I use mbox format many times. I find it comfortable > but was going to try maildir. But it the time taken is large i wont' The only really safe answer is, try it and see. Pick a few of your bigger folders, open 'em up in mutt, tag ~A, then ;s to a maildir. "x" to exit without saving, or T~A and ;u to undelete them, then turn mutt to the maildir and see whether it hurts. There is not one answer. Here are some factors: - On some filesystems (most older ones), all operations related to directories, including opening every file in the directory to read it, get slow quadratically in directory size (O(N^2)), rather than the O(NlogN) you expect from well-chosen data structures. - Opening a file, reading from it, and closing it is more expensive than doing a few short reads, regardless. The first point means that if you aren't using ext3+hashdirs, Reiserfs, WAFL, XFS, or whatever other modern filesystems have good large-dir performance, Maildir folders with many thousands of messages will get slow, regardless. The second point means that if you have many thousands of messages in a folder, and they aren't particularly large messages, mbox will be way faster to open the folder, no matter what. But the flip side of that latter point is that if you have many _huge_ messages, let's say 1MB or bigger (that's a guess, the breakeven point might be bigger or smaller than that by an order of magnitude for all I know, and will certainly vary from platform to platform) Maildir can get faster than mbox to open. Other operations have different performance tradeoffs. Deleting the first message in a Maildir is quick and cheap; deleting the first message in a gigantic mbox requires copying the entire thing, which is neither quick nor cheap. It can be done in place, but will still take a lot of time, and if done in-place a crash during the long slow operation will leave the mbox corrupt. Adding messages to, removing messages from, and changing the status of messages in a folder are operations that are simple, safe, atomic, and quick with Maildir; they scale with mbox size and the position of the message in the mbox for mbox format folders. Maildir folders are easily manipulated with normal shell tools, mbox folders need parsers and clever logic to do message-by-message manipulations on them. -Bennett
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