Important dependency to also check out:
"doctrine/dbal": "~2.4"

I'm a bit worried about the update script - it looks like it wants to directly modify the schema. It'd make more sense in our environment to spit out the SQL that would modify it.

Also, not to be a tool bigot - but it'd be neat to implement an Elasticsearch backed version of this - it'd be simpler in many ways. Probably more complex in others.

Re update script: we are aware of this. The CLI can already dump the schema creation code for exactly that purpouse

Note there is a test in the performance group that is excluded by default. I used this to get a quick idea of how quick inserts are, at least when there is little data in the store. https://github.com/wmde/WikibaseQueryEngine/blob/master/tests/Integration/PerformanceTest.php

Poke for status - I'm really just looking for some general hint on Ori would be able to start the review. Or if I should bounce to Aaron?

Swapping over to Aaron because Ori is crushed under HHVM.

Some status on this - the tool is being rewritten to remove its dependency on external libraries. If possible it'd be cool to get started on the review before the rewrite. It _shouldn't_ be a huge rewrite - just replacing some of it.

the tool is being rewritten

It is not being "rewritten" - most of it will remain the same.

to remove its dependency on external libraries

That is being done, though does not involve rewriting the component.