progress notification for long queries

[riastradh-probcomp]

There is partial support for a progress hook, but it is not called everywhere it should be. It should be invoked at every iteration of a metamodel function, and perhaps sometimes in the metamodel itself so that long-running metamodel functions (e.g., ANALYZE) do not block application responsiveness.

[gregory-marton]

Is a research project?

[riastradh-probcomp]

Is this a research project? No, not really. Just a matter of sprinkling more calls to the progress hook, and maybe providing a way for the metamodel to call it too.

There is a potentially related research project which maps queries to counting-queries which approximate an upper bound on how long the original queries might take, in order to show not merely an amount of progress but a fraction of progress.