I forgot to mention that the bug can be reproduced in a hot-standby
setup with the attached isolation spec. Note that full_page_writes must
be turned off (otherwise, the updates use full-page writes and then the
bogus code is not run). Once the spec is executed, in the replica run
SET enable_seqscan TO off;
SELECT * FROM f WHERE a=1;
and you get no rows back.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services