Support PostgreSQL-12
PostgreSQL-12 seems to have a bug when casting the result of EXTRACT EPOCH into NUMERIC.
This can be seen with such query:
SELECT EXTRACT(EPOCH FROM '2019-10-29 17:35:54.176655'::timestamp), CAST(EXTRACT(EPOCH FROM '2019-10-29 17:35:54.176655'::timestamp) AS NUMERIC);
But the timestamp checking is using the epoch of last write timestamp cast into VARCHAR (to avoid rounding issue with client language (ex: Javascript)). The comparison is done by casting the values into NUMERIC. So as PostgreSQL is rounding to 5 digits the EPOCH when casting to NUMERIC, the check fails.
I think the best is to use FLOAT instead of NUMERIC.