Thank you xbgmsharp for sharing your thoughts. Here are my replies :-)

xbgmsharp wrote:

More database support would help PWG popularity.

I don't think so. Piwigo may get attention from "a few" technical people but not from "mainstream users". Of course attracting tech people is important, but that does not make the application "popular".

In my opinion, here are a few ideas to make Piwigo more popular:

* having a sexier piwigo.org website (work in progress, early stage)
* having a "network" between existing Piwigo so that you can get visibility from other Piwigo users (work in progress, very early stage)
* having more modern themes
* improve user experience with "even" better administration screens

I honestly don't believe that running Piwigo on PostgreSQL/SQLite/WhateverDB will make it more popular.

What matters most is that Piwigo requirements are available on every shared hosting provider, and that's the case. PHP + MySQL is certainly the most common technical technology stack available.

xbgmsharp wrote:

Having a great database abstraction layer would make it easier plugins.
It would avoid dirty unsecured SQL query in plugins.

I agree. We could certainly have a better abstraction layer (we already have one) and the prepared statements are very interesting in my opinion. But there are different levels of abstraction : some completely remove the necessity to write SQL queries. It's great for developers who don't like SQL (personaly I like it) but it leads to very bad performances and implies to use several levels of cache...

xbgmsharp wrote:

Most Open Source web application support multiple database.

You mean like Wordpress or Piwik? ;-) I took just those 2 examples to show you don't need to support multiple databases to be "popular".

xbgmsharp wrote:

Even if some specific MySQL function does not exist, there is available workaround, not always easy but technically possible.

so you mean an abstraction layer where we would sill write SQL queries, just like we did in Piwigo 2.2. Why wouldn't it raise the exact same problem that lead to the decision to drop Pg/SQLite support 3.5 years ago?

xbgmsharp wrote:

MySQL vs MariaDB is also a concern for the very long term.

Piwigo is perfectly compatible with MariaDB :-)