Robert Haas <robertmh...@gmail.com> writes: > On Tue, Mar 6, 2012 at 10:21 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> But having said that, it's not apparent to me why such a thing would >> need to live "inside the database" at all. It's very easy to visualize >> a task scheduler that runs as a client and requires nothing new from the >> core code. Approaching the problem that way would let the scheduler >> be an independent project that stands or falls on its own merits.
> But since you brought it up, I think there is a lot of value to having > a scheduler that's integrated with the database. There are many > things that the database does which could also be done outside the > database, but people want them in the database because it's easier > that way. If you have a web application that talks to the database, > and which sometimes needs to schedule tasks to run at a future time, > it is much nicer to do that by inserting a row into an SQL table > somewhere, or executing some bit of DDL, than it is to do it by making > your web application know how to connect to a PostgreSQL database and > also how to rewrite crontab (in a concurrency-safe manner, no less). Sure, and I would expect that a client-side scheduler would work just the same way: you make requests to it through database actions such as inserting a row in a task table. > Now, the extent to which such a schedule requires core support is > certainly arguable. Maybe it doesn't, and can be an entirely > stand-alone project. pgAgent aims to do something like this, but it > has a number of deficiencies, including a tendency to quit > unexpectedly and a very klunky interface. Well, if they didn't get it right the first time, that suggests that it's a harder problem than people would like to think. All the more reason to do it as an external project, at least to start with. I would much rather entertain a proposal to integrate a design that's been proven by an external implementation, than a proposal to implement a design that's never been tested at all (which we'll nonetheless have to support for eternity, even if it turns out to suck). regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers