According to all accounts I could find, the sqllite databases created using the --database ( defaults to true since 2010, createrepo-0.9.9) option to createrepo/mergerepo is an *client optimization only*.
Where access to Nexus is highly concurrent, and all yum clients seem to support the basic mode without sqlite files on the server just fine, we should therefore stop asking createrepo.mergerepo to create the sqllite databases.
This in theory should improve metadata creation performance(TBD), increase locking throughput and avoid the possibility of having xml based metadata out of sync from sqllite data.
Since 2010, createrepo and mergerepo have added the --no-database option to prevent creation of the sqlite metadata. Before 0.9.9 version, no sqlite data was being created unless specifically asked.
These commits changed the default createrepo/mergerepo behavior from not creating sqlite databases to creating them.
Further, YUM documentation ( and code if you look hard enough) clarifies that if sqlite files are not found, YUM falls back to getting the XML files instead.
Our code uses --database option, thereby always creating sqlite databases on the server.
- our commands should remove -d, --database and add --no-database
- we should clearly specify we require createrepo 0.9.9 or greater to be used OR provide some override to not pass the --no-database option to createrepo/mergerepo in case the local version does not recognize this option
- if implemented, YUM clients can call yum clean dbcache locally to clean up any previously "downloaded from Nexus" sqlite databases and from then on generate their own sqlite files from the xml data only
- YUM clients could configure 'mddownloadpolicy' in yum.conf to be xml, as a very slight optimization when known to be talking to Nexus, but not required
- on upgrade after this change, delete any sqlite files in Nexus repos to avoid clients from downloading them in the future and getting even more confused, or something more slightly confusing, always responding 404 even if they exist