Stuart Bishop shaped the aether to ask:
> Hi.
>
> I need to measure how far in the past a hot standby is, async
> streaming replication.
>
Not sure if this will help, but we are using repmgr <https://github.com/greg2ndQuadrant/repmgr>; it sets up a monitoring schema which we poll )see the "Monitoring and Testing" section ... study their source code some and see how they come up with lag times.
HTH,
Greg WiIliamson
DBA
Powerreviews dot com