Some storage providers e.g. S3 don't have an efficient rename operation.
Before this change, when chunker finished an upload, the server-side copy
and delete operations that renamed temporary chunks to their final names
could take a significant amount of time.
This PR records transaction identifier (versioning) in the metadata of
chunker composite objects striving to remove the need for rename
operations on such backends.
This approach will be triggered be the new "transactions" configuration
option, which can be "rename" (the default) or "norename".
We implement the new approach for uploads (Put operations).
The chunker Move operation still uses the rename operation of
underlying backend. Filling this gap is left for a later PR.
Co-authored-by: Ivan Andreev <ivandeex@gmail.com>
- fix test case FsNewObjectCaseInsensitive (PR #4830)
- continue PR #4917, add comments in metadata detection code
- add warning about metadata detection in user documentation
- change metadata size limits, make room for future development
- hide critical chunker parameters from command line
changes:
- chunker: remove GetTier and SetTier
- remove wdmrcompat metaformat
- remove fastopen strategy
- make hash_type option non-advanced
- adverise hash support when possible
- add metadata field "ver", run strict checks
- describe internal behavior in comments
- improve documentation
note:
wdmrcompat used to write file name in the metadata, so maximum metadata
size was 1K; removing it allows to cap size by 200 bytes now.
