I registered as reviewer on this, but after reading the whole thread for the second time, it's still not clear to me if the last two submitted patches (0001-Add-auto_explain.publish_plans.patch and 0002-Add-SHM-table-of-contents-to-the-explain-DSM.patch) are still needed reviews, since multiple refactoring ideas and objections have been raised since.
I looked into it more deeply and decided partial EXPLAINs aren't very useful yet.
I've got some thoughts around that which I'll publish when I have more time. I suggest this is a good idea, just needs some serious committer-love, so we should bounce this for now.
I have the plans to make something from this on top of pg_stat_statements and auto_explain, as I've mentioned last time. The next iteration will be based on the two latest patches above, so it still makes sense to review them.
As for EXPLAIN ANALYZE support, it will require changes to core, but this can be done separately.
