I agree with Barry. You can create a folder or a file with pseudo-random names. I recommend you to use str(uuid.uuid4())
On Sat, 1 Jan 2022 at 14:11, Barry <ba...@barrys-emacs.org> wrote: > > > > > On 31 Dec 2021, at 17:53, iMath <redstone-c...@163.com> wrote: > > > > 在 2021年12月30日星期四 UTC+8 03:13:21，<Marco Sulla> 写道： > >>> On Wed, 29 Dec 2021 at 18:33, iMath <redsto...@163.com> wrote: > >>> But I found the size of the file of the shelve data didn't change much, > >>> so I guess the data are still in it , I just wonder any way to recover my > >>> data. > >> I agree with Barry, Chris and Avi. IMHO your data is lost. Unpickling > >> it by hand is a harsh work and maybe unreliable. > >> > >> Is there any reason you can't simply add a semaphore to avoid writing > >> at the same time and re-run the code and regenerate the data? > > > > Thanks for your replies! I didn't have a sense of adding a semaphore on > > writing to pickle data before, so corrupted the data. > > Since my data was colleted in the daily usage, so cannot re-run the code > > and regenerate the data. > > In order to avoid corrupting my data again and the complicity of using a > > semaphore, now I am using json text to store my data. > > That will not fix the problem. You will end up with corrupt json. > > If you have one writer and one read then may be you can use the fact that a > rename is atomic. > > Writer does this: > 1. Creat new json file in the same folder but with a tmp name > 2. Rename the file from its tmp name to the public name. > > The read will just read the public name. > > I am not sure what happens in your world if the writer runs a second time > before the data is read. > > In that case you need to create a queue of files to be read. > > But if the problem is two process racing against each other you MUST use > locking. > It cannot be avoided for robust operations. > > Barry > > > > -- > > https://mail.python.org/mailman/listinfo/python-list > > -- > https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
