Improve reliability of upload retries and B2 file deletions #3885
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When hard deleting the latest file version on B2, this uncovers earlier versions. If an upload required retries, multiple version might exist for a file. Thus to reliably delete a file, we have to remove all versions of it.
For backends which are able to atomically replace files, we just can overwrite the old copy, if it is necessary to retry an upload. This has the benefit of issuing one operation less and might be beneficial if a backend storage, due to bugs or similar, could mix up the order of the upload and delete calls.
Just request as many files as possible in one call to reduce the number of network roundtrips.
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#3893 showed no problems, so let's merge this. There's no test to specifically check that the delete retry loop for B2 completely works as expected, but the backend tests work, so the normal case is at least working fine. |
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What does this PR change? What problem does it solve?
When hard deleting the latest file version on B2, this uncovers earlier versions. If an upload required retries, multiple version might exist for a file. Thus to reliably delete a file, we have to remove all versions of it. Otherwise symptoms like #3161 or even data loss can be the result.
This change allows the retry backend to skip deleting failed uploads for backends that support atomic file replacements. For these backends we just can overwrite the old copy, if it is necessary to retry an upload. This has the benefit of issuing one operation less and might be beneficial if a backend storage, due to bugs or similar, could mix up the order of the upload and delete calls.
As a random additional change the PR also increases the file listing size for B2 to the maximum in order to reduce the number of network roundtrips necessary to list the files in a large repository.
There is currently only a changelog for the B2 delete change as the other ones only affect extremely technical details.
Was the change previously discussed in an issue or on the forum?
Fixes #3161
Checklist
[ ] I have added documentation for relevant changes (in the manual).changelog/unreleased/that describes the changes for our users (see template).gofmton the code in all commits.