Re: Creating a series of sequenced files
Re: Creating a series of sequenced files
- Subject: Re: Creating a series of sequenced files
- From: Carl Hoefs <email@hidden>
- Date: Sat, 16 Apr 2016 15:29:50 -0700
> On Apr 16, 2016, at 3:20 PM, Quincey Morris <email@hidden> wrote:
>
> On Apr 16, 2016, at 15:10 , Carl Hoefs <email@hidden <mailto:email@hidden>> wrote:
>>
>> But I'm concerned mainly with efficiency, as determining the next number in the naming sequence potentially can be extremely inefficient - trying 1000s of times until the next available number every time a new file needs to be written, and also every time the latest-written file needs to be retrieved.
>
> If you really need to examine the existing files, then I suggest you start your process with a one-time directory enumeration, and find the file that you regard as "last". However I foresee that there are actually two things you might want to find:
>
> 1. The next sequence number to use.
>
> 2. The most recently-written file.
>
> There’s really nothing you can do to guarantee that these are the same, in all scenarios, so you may as well treat them as separate results.
>
> This would only get complicated if there’s another process creating files in your sequence. Otherwise an initial directory enumeration will get you sync-ed up, and after that you can just do the simple nextInSequence-incrementing thing.
>
For a single sequence, it wouldn't be so bad, but I have potentially n different ongoing sequences, so it seems like this approach could end up hitting the filesystem really hard. I'll code it up and see how inefficient it becomes.
-Carl
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