I'm doing some reporting-type work with PG, with the vast majority of queries hitting upwards of 25% of the table, so being executed as seq scans. It's a fairly large set of data, so each pass is taking quite a while, IO limited. And I'm looking at doing dozens of passes. It would be really nice to be able to do all the work with a single pass over the table, executing all the queries in parallel in that pass. They're pretty simple queries, mostly, just some aggregates and a simple where clause. There are some fairly obvious ways to merge multiple queries to do that at a SQL level - converting each query into a function and passing each row from a select * to each of the functions would be one of the less ugly. Or I could fire off all the queries simultaneously and hope they stay in close-enough lockstep through a single pass through the table to be able to share most of the IO. Is there a commonly used trick to doing this that I should know about? Cheers, Steve
