Checking Postgres Streaming replication delay

[Patrick B <patrickbakerbr@xxxxxxxxx>]

Hi guys,

I'm using this query to measure the delay between a Master and a Streaming Replication Slave server, using PostgreSQL 9.2.

SELECT
pg_last_xlog_receive_location() receive,
pg_last_xlog_replay_location() replay,
(
extract(epoch FROM now()) -
extract(epoch FROM pg_last_xact_replay_timestamp())
)::int lag;

In your opinion, is that right?

Cheers

Patrick