Investigate test failure with order_by.limit changefeed

[danielmewes]

I'm currently working on a fuzzing test for a few additional changefeed queries (currently available at

rethinkdb/test/rql_test/init_fuzz_various_queries.rb

Line 23 in bc401bb

#$tbl.order_by(index: :id).limit(5),

). If I enable the query $tbl.order_by(index: :id).limit(5), the test gets stuck.

Maybe the changefeed never becomes ready?

[danielmewes]

The test is at

rethinkdb/test/rql_test/init_fuzz_various_queries.rb

Line 23 in bc401bb

#$tbl.order_by(index: :id).limit(5),

[danielmewes]

The server also gets stuck in "Shutting down client connections..." during shutdown and must be killed.

[danielmewes]

The issue of rethinkdb not shutting down can seemingly be resolved by replacing line 2687 in changefeed.cc by

nap(50, env->interruptor);

(the interruptor was added)

However the test still hangs, so I suspect that something else is wrong.

[mlucy]

This appears to be caused by the .orderby.limit changefeed preventing one or more of the range changefeeds from becoming ready. .orderby.limit changefeed messages consume timestamps from the same pool as the range changefeed messages, so there's probably somewhere where we're expecting sequential timestamps but not getting them.

[mlucy]

A fix for this is in CR 3408 by @danielmewes .

[danielmewes]

Moving this into the 2.2.3 release. Since we couldn't release last week because of some technical issues, we are going to retag and release 2.2.3 with two additional bug fixes instead.

[mlucy]

This is in next and 2.2.x.