Until recently, pg_relation_size used SearchSysCache to locate the
relation to examine, and calculated the file location from that
information. Starting with dbsize.c V1.5 (committed after Beta2),
relation_open(.., AccessShareLock) is used. This is very unfortunate
because it will not allow to observe a table growing while it is
populated, e.g. with a lengthy COPY; pg_relation_size will be blocked.
After reverting to 1.4, everything was fine again.
Can we have this reverted/fixed?
Regards,
Andreas