Tino Wildenhain escribió: > Which makes me think if the solution would be to just run CLUSTER under > the hood when VACUUM FULL is requested. Would that introduce any > other problems? The difference is that CLUSTER requires double the disk space in table + indexes. VACUUM FULL has no such requirement. A possibly approach would be to do an ANALYZE (to have fresh stats about dead tuple density), and do a CLUSTER if the density is too high. There has been talk about rewriting VACUUM FULL anyway; it's complex code and it introduces extra complications in other parts of code that would be otherwise unneeded, e.g. HOT. I have no idea what a rewritten VACUUM FULL would look like, though. Another thing we should do in this area is rewrite CLUSTER to use a seqscan + sort instead of indexscan when the heap/index order correlation is low. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.
