<blockquote>
<p>And are you really saying that rewriting a column doesn't need to lock the whole set of chunks anyway? Can it really cope with half the chunks being in the old schema and half in the new schema?</p>
</blockquote>
<p>Taking the nodes table with it's 8-12 billion rows as the worst, if we had 1 billion node partitions, we could do the column rewrite on all of them in parallel, and then rewrite the indexes on all of them at the same time.</p>

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