On Fri, Nov 20, 2009 at 10:47 PM, Ryan Chan <ryanchan...@gmail.com> wrote: > Any reason I would like to ask is why not use PostgreSQL? > > Seems MySQL is not suitable for handling large table (e.g. over few > GB), I just wonder why wikipedia don't use PostgreSQL? > > It should provide better performance.
MySQL is easily capable of handling very large tables, if used properly. Certainly tables the size of Wikipedia's (which aren't very big by DB standards). Selecting a list of all titles that are not redirects will take a long time on any database, unless you have everything in memory, because it requires a table scan -- there's no index that covers the relevant columns (IIRC). Of course, if you don't configure MySQL properly, or don't give it a reasonable amount of hardware, it will perform poorly, but the database is not much overtaxed on Wikipedia right now. It's also worth pointing out that Wikipedia uses a version of MySQL with substantial modifications, and Wikimedia sysadmins are very familiar with its behavior. Switching to a new technology might theoretically be better in the long term (although I wouldn't take that for granted in this case), but the transition cost would be substantial. Heck, Wikipedia hasn't even upgraded to MySQL 4.1, let alone a whole different DBMS. _______________________________________________ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
