publish: reenable unlocking measurements

[juliangruber]

No description provided.

[bajtos]

The index seems to work now. Your change should be safe to land & deploy. 👍🏻

EXPLAIN ANALYZE UPDATE measurements SET lock = NULL WHERE lock IS NOT NULL;
                                                               QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------
 Update on measurements  (cost=0.12..2.34 rows=0 width=0) (actual time=0.010..0.010 rows=0 loops=1)
   ->  Index Scan using measurements_locked on measurements  (cost=0.12..2.34 rows=1 width=38) (actual time=0.009..0.009 rows=0 loops=1)
         Index Cond: (lock IS NOT NULL)
 Planning Time: 0.101 ms
 Execution Time: 0.121 ms
(5 rows)