> You might want to take a look at this: > http://wiki.postgresql.org/wiki/Submitting_a_Patch
I will; I'm sorry it wasn't in the proper format. It was just a proof of concept, I guess I should have talked about it before even sending the patch. > As to the content of the patch, I think that what you are > doing is > comparing the actual number of "operations" with the > expected number > of operations. If that's correct, I'm not sure it's > really all that > useful, because it will only give you accurate > percentage-of-completion information when the estimates are > correct. > But when the estimates are correct, you probably have a > pretty good > idea how long the query will take to run anyway. That would be a first step. Having an idea of how much a query "progressed" is very important for long-running queries. It's like copying files: even if you have a rough idea of how much time a copy will take, having an interface that tells you the percentage done is quite useful (IMHO). > When > the estimates > are off, you'll find that the actual number of operations > is more than > the expected number of operations, but that won't really > tell you how > far you have to go. The second phase would be using histograms to help refine the statistics at runtime. > The only other use case I can think of for functionality of > this type > is some kind of dashboard view on a system with very > long-running > queries, where you want to see how far you have yet to go > on each one > (maybe to approximate when you can submit the next one) > without having > detailed knowledge of how expensive each individual query > was project > to be. But that's a pretty narrow use case I don't think it's that narrow: it is important, for long running queries, to know how far the query processed (the user wants to know how much of a query has yet to be executed). That's why you find so many papers on query progress indicators. The real problem is that they don't give you a solution :) > Greg Stark was (is?) working on a way to get > EXPLAIN-ANALYZE type > statistics on running queries; you might want to take a > look at some > of that work and see what you think. > > http://wiki.postgresql.org/wiki/Greg_Stark%27s_Development_Projects#EXPLAIN_queries_in_progress > That's interesting. I'll take a look! Thank you very much for your comments. Is anyone interested in such a progress indicator??? -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
