Whoops I forgot to mention in the list post -- we're planning to talk about this topic in the public ArchCom IRC meeting this Wednesday (21:00 UTC / 2pm PDT). Already getting good feedback on the page, am updating it, and looking forward to more.... Thanks all. :) -- brion On Mon, Feb 13, 2017 at 9:28 AM, Brion Vibber <bvibber(a)wikimedia.org> wrote:

Correction: 22:00 UTC / 2pm PST in #wikimedia-office. Sorry, I calculated with the wrong time by mistake! -- brion On Tue, Feb 14, 2017 at 10:38 AM, Brion Vibber <bvibber(a)wikimedia.org> wrote:

On Wed, Feb 15, 2017 at 3:06 PM, Brion Vibber <bvibber(a)wikimedia.org> wrote: We're going to have another checkin during ArchCom IRC meeting time this Wednesday, 22:00 UTC / 2pm PST in #wikimedia-office Documents will be updated shortly reflecting the previous discussion & ongoing tweaks. Open questions include: * should we go straight to the MCR-ready schema or do this in two steps, one to break up tables & prep, and another for the MCR content model? * final model for updating archive & text -- brion

On Mon, 6 Mar 2017 at 16:52 MZMcBride &lt;z(a)mzmcbride.com&gt; wrote: Yes. Correct; it'd take down the cluster. Are you planning to write separate maintenance scripts for this? Yes. As is "normal" with schema changes, in Wikimedia production this will be done manually by the DBAs <https://wikitech.wikimedia.org/wiki/Schema_changes>. It is a careful, very slow process that manages the otherwise-impossible. It will take months of their time, is seriously laborious, and blocks any other such changes. A recent user-facing example is T69223 <https://phabricator.wikimedia.org/T69223>, which was required to support translation from non-English languages on multi-content wikis. This is why the DBAs' views are so important. :-) Once the schema change is done, we may/will back-fill old rows to populate the new schema, using maintenance scripts for each wiki. However, given that the table we're talking about is revision with over three quarters of a billion rows on enwiki alone, that will be exceptionally slow-running. Once all *that* is done, we could do a further schema change to drop the old bits of the schema that are no longer used (again, slow), and then drop the backwards-compatible database code from MediaWiki. But that's optional. Regarding scope, this is a lot of changes. How are all of these changes Yes, but given that this round will take years to complete, deciding to delay some of the things means upsetting a lot of plans. J. -- James D. Forrester Lead Product Manager, Editing Wikimedia Foundation, Inc. jforrester at wikimedia.org <https://lists.wikimedia.org/mailman/listinfo/wikimedia-l> | @jdforrester