Strange problem

I have an application that parses web server log files, and inserts a
few million rows into a table each month, one table per month. Lately,
I've been getting reports that there is no recent data, so I went
looking.  I'll concentrate on the first table that seems to have an
issue because there are a few, all seemingly the same. \dt+ shows the
table size of 6463 MB.  OK, there's data there. "select count(*) from
table" comes back with 0; "select ctid from table" comes back with 0,
but after a while. pg_dump or pg_dumpall completely skip the table.

I'm not a complete novice, but I'm stumped. No errors in the OS system
logs, postgres starts and stops with no errors. This is running on
ubuntu 14.04.03, with postgres 9.3

Tim