Simon Riggs <[EMAIL PROTECTED]> writes: > I'm happy with the idea of a readahead process. I thought we were > implementing a BackgroundReader process for other uses. Is that dead > now?
You and Bruce seem to keep resurrecting that idea. I've never liked it -- I always hated that in Oracle and thought it was a terrible kludge. I think the inter-process communication would be way too heavy-weight, by the time the other process is schedule the process which needed the blocks would have probably have done many of them already anyways. Worse, you would need a large number of reading processes and would start to run into locking contention on the work-queue as well. In any case it would be a lot of code to do what posix_fadvise does for us with a simple syscall anyways. Am I misjudging this? Is this a popular idea? We could always implement it as a fall-back implementation for mdprefetch() where posix_fadvise (and libaio assuming we implement that as well) don't work. It has the advantage of working with any system at all even if it predates 1003.1. But it seems like an awful lot of code to implement a solution that I fear won't work very well. And are people running raid arrays not likely to be running modern OSes anyways? -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production Tuning -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
