= DNF: Do not download filelists by default = This document represents a proposed Change. As part of the Changes process, proposals are publicly announced in order to receive community feedback. This proposal will only be implemented if approved by the Fedora Engineering Steering Committee.
Wiki: https://fedoraproject.org/wiki/Changes/DNFConditionalFilelists == Summary == Change the DNF behavior to not download filelists by default. These metadata, which describe all the files contained within each package, are unnecessary in the majority of use cases. Additionally, these metadata files can be large in size, leading to a significant slowdown in the user experience. == Owner == * Name: [[User:jkolarik| Jan Kolarik]] * Email: jkola...@redhat.com == Detailed Description == Until now, filelists were always downloaded together with other metadata. This was hardcoded and unable to change from the outside of DNF. With these changes, we are proposing to not download the filelists metadata by default. This default behavior can be modified through the new DNF configuration option. Additionally, specific commands can override this behavior and request loading the filelists metadata at runtime using the existing demands object in DNF. Note that after this change, users can still use DNF without filelists metadata when querying file provides located in `/usr/bin`, `/usr/sbin` or `/etc` directories. == Feedback == == Benefit to Fedora == As DNF is integral to various infrastructure tasks like package building and installation, testing environment creation, and server integration tests, this change significantly reduces processing time and resource usage for these processes. This change reduces the RAM requirements of the DNF process, addressing existing issues when running the Fedora system on low-memory machines such as the Raspberry Pi (see f.e. [https://bugzilla.redhat.com/show_bug.cgi?id=1907030 Bug 1907030]). Also, omitting the filelists metadata download overall decreases the costs of a Fedora mirror server operation. == Scope == * Proposal owners: ** libdnf *** Modify the `Repo` object to enable conditional filelists metadata download *** Introduce a new main configuration option to set the default behavior ** dnf *** Enable configuration of filelists download from commandline, DNF commands and DNF plugins *** Implement filename pattern argument detection heuristics * Other developers: <!-- REQUIRED FOR SYSTEM WIDE CHANGES --> ** Dependencies using the existing DNF C interface may need to adapt if they expect the filelists metadata to be available and explicitly request loading filelists using the existing API due to this change: *** PackageKit *** microdnf *** API users * Release engineering: N/A * Policies and guidelines: ** Package maintainers must follow Fedora's packaging guidelines, particularly concerning file dependency specifications (see [https://docs.fedoraproject.org/en-US/packaging-guidelines/#_file_and_directory_dependencies here]) * Trademark approval: N/A * Alignment with Community Initiatives: N/A (no currently active initiatives) == Upgrade/compatibility impact == In general, applying these changes should not affect any existing user workflows and no additional manual changes are required. However, the absence of filelists might create an issue with packages that are not correctly packaged or originate from third-party repositories. In the current Fedora release repository, there are only a few such packages, see the [https://bugzilla.redhat.com/show_bug.cgi?id=2180842#c8 comment] in [https://bugzilla.redhat.com/show_bug.cgi?id=2180842 Bug 2180842]. == How To Test == When using DNF commands without a filename pattern passed as the argument, filelists metadata should not be downloaded from the remote repositories and should not be needed for the command execution. This can be tested with the following steps: * Clean the local metadata cache (`dnf clean metadata`) * Run a DNF command not involving the filename spec (e.g. `dnf repoquery rpm`) * Verify that no `*-filelists.*` metadata files were downloaded inside the cache subdirectories (by default under the `/var/cache/dnf` for root) * Check the command works as expected The same should also apply to RPM package arguments (files ending with `.rpm` extension). When using DNF commands with a filename pattern passed as the argument, filelists metadata should be downloaded from the remote repositores as before. == User Experience == Large filelists could be over 200MB in size. It could take 1-2 minutes to download which is greatly slowing down the user experience. For many operations the filelists metadata are not needed, so downloading them is wasting the resources. Without filelists being downloaded, DNF performance will be improved significantly, mainly regarding the network, CPU and disk space resources. Metadata download size will be reduced by about 60%. The improvement includes deployments of customer built RPMS to containers that have no need for filelists level dependencies. == Dependencies == No changes should be required for any package depending on DNF to implement this behavior. == Contingency Plan == * Contingency mechanism: Change the configuration option to download the filelists by default * Contingency deadline: Branch Fedora Linux 40 from Rawhide * Blocks release? No == Documentation == Links to the relevant DNF CLI and API documentation sections will be provided here once the related pull request is created. == Release Notes == -- Aoife Moloney Fedora Operations Architect Fedora Project Matrix: @amoloney:fedora.im IRC: amoloney _______________________________________________ devel-announce mailing list -- devel-announce@lists.fedoraproject.org To unsubscribe send an email to devel-announce-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel-announce@lists.fedoraproject.org Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
