fix(jdbc-postgres): drop the queues_pk and use an hash index instead (#…

…2277)

This avoids the queues_pkey index to be used by the poll query which is suboptimal.

jdbc-postgres/src/main/resources/migrations/postgres/V1_3__postgres-queues-pkey.sql

@@ -0,0 +1,5 @@
+-- We drop the PK, otherwise its index is used by the poll query which is sub-optimal.
+-- We create an hash index on offset that will be used instead when filtering on offset.
+ALTER TABLE queues DROP CONSTRAINT IF EXISTS queues_pkey;
+
+CREATE INDEX IF NOT EXISTS queues_offset ON queues USING hash ("offset");