PostgreSQL 12 High Availability Cookbook - Third Edition

How to do it...

All queries in this recipe should be performed by the bench_user mapped user in the pgbench database on the pg-report PostgreSQL server. Follow these steps:

1. Execute the following simple query to view a remote query plan:

EXPLAIN VERBOSE 
SELECT aid, bid, abalance 
  FROM pgbench_accounts 
 WHERE aid BETWEEN 500000 AND 500004; 

2. Execute the following SQL statement to examine how PostgreSQL handles remote aggregates:

EXPLAIN VERBOSE 
SELECT sum(abalance) 
  FROM pgbench_accounts 
 WHERE aid BETWEEN 500000 AND 500004; 

3. Execute the following SQL statement to see a query plan involving a JOIN:

EXPLAIN VERBOSE SELECT a2.aid, a2.bid, a2.abalance FROM pgbench_accounts a1 JOIN pgbench_accounts a2 USING (aid) WHERE a1.aid BETWEEN 500000 AND ...