On 21 Leden 2012, 18:20, Dimitri Fontaine wrote: > Hi, > > Thank you for reviewing this patch! > > Hitoshi Harada <umi.tan...@gmail.com> writes: >> >> Next, some questions: >> - Why is the finer dependency needed? Do you have tangible example >> that struggles with the dependency granularity? I feel so good about >> the existing dependency on extension as an extension developer of >> several ones. > > The problem is not yet very apparent only because extensions are very > new. The main thing we address with this patch is depending on a feature > that appeared while developing an extension or that gets removed down > the line. It allows to depend on features and avoid needing to compare > version numbers and maintain a list of which version number is providing > which feature. > > This feature has been asked by several extension users, beginning even > before 9.1 got released.
It's also about several extension providing the same sort of functionality implemented in different ways. Think about extensions that allow you to send e-mails right from the database. One could do that directly, the other one could implement queuing, another one could be optimized for a specific SMTP server. With features, you could just say 'require = mail' and use the extension that's installed. Yes, this needs a common API. I personally see this as a major step towards fully-fledged package management, similar to those available in modern Linux distributions (apt, yum, portage, ...). Tomas -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers