On 7 December 2010 19:10, Robert Haas <robertmhaas@xxxxxxxxx> wrote: >> I'm not very familiar with PostgreSQL code but if we're >> brainstorming... if you're only trying to protect against a small >> number of expensive operations (like DROP, etc.) that don't really >> happen often, wouldn't an atomic reference counter be good enough for >> the purpose (e.g. the expensive operations would spin-wait until the >> counter is 0)? > > No, because (1) busy-waiting is only suitable for locks that will only > be held for a short time, and an AccessShareLock on a table might be > held while we read 10GB of data in from disk, Generally yes, but a variant with adaptive sleeping could possibly be used if it would be acceptable to delay (uncertainly) the already expensive and rare operations. > and (2) that wouldn't > allow for deadlock detection. Probably :) -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
