<story><title>GitHub&apos;s online schema migration for MySQL</title><url>https://github.com/github/gh-ost</url></story><parent_chain><item><author>perlgeek</author><text>We evaluated gh-ost, but the killer for us is that it doesn&amp;#x27;t support any kind of foreign keys.&lt;p&gt;I understand that at GitHub&amp;#x27;s scale, foreign keys might be more of a hassle than what they are worth, but for a smallish company that values data integrity over scale and uptime, this is not an acceptable choice.</text></item></parent_chain><comment><author>shlomi-noach</author><text>Author of gh-ost here. Actually, it should be possible to support child-side foreign keys. They would have to be named differently (the foreign key constraint has a unique name in a schema) -- but it should work. See discussion in &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;github&amp;#x2F;gh-ost&amp;#x2F;issues&amp;#x2F;507&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;github&amp;#x2F;gh-ost&amp;#x2F;issues&amp;#x2F;507&lt;/a&gt;&lt;p&gt;It is true that it is not on our roadmap to implement FK support for gh-ost (see &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;github&amp;#x2F;gh-ost&amp;#x2F;issues&amp;#x2F;331&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;github&amp;#x2F;gh-ost&amp;#x2F;issues&amp;#x2F;331&lt;/a&gt;), but if anyone wishes to contribute support for FK we&amp;#x27;re grateful. We&amp;#x27;ve had more complex contributions coming from the community and we&amp;#x27;re grateful for those.</text></comment>
<story><title>GitHub&apos;s online schema migration for MySQL</title><url>https://github.com/github/gh-ost</url></story><parent_chain><item><author>perlgeek</author><text>We evaluated gh-ost, but the killer for us is that it doesn&amp;#x27;t support any kind of foreign keys.&lt;p&gt;I understand that at GitHub&amp;#x27;s scale, foreign keys might be more of a hassle than what they are worth, but for a smallish company that values data integrity over scale and uptime, this is not an acceptable choice.</text></item></parent_chain><comment><author>cup-of-tea</author><text>I&amp;#x27;m interested to know what companies are doing &amp;quot;at scale&amp;quot; to not need to use foreign keys. Do they just write user ids or whatnot into other tables?</text></comment>