On 02-04-2015 AM 09:24, Jim Nasby wrote: > The other potential advantage (and I have to think this could be a BIG > advantage) is extending by a large amount makes it more likely you'll get > contiguous blocks on the storage. That's going to make a big difference for > SeqScan speed. It'd be interesting if someone with access to some real systems > could test that. In particular, seqscan of a possibly fragmented table vs one > of the same size but created at once. For extra credit, compare to dd bs=8192 > of a file of the same size as the overall table. >
Orthogonal to topic of the thread but this comment made me recall a proposal couple years ago[0] to add (posix_)fallocate to mdextend(). Wonder if it helps the case? Amit [0] http://www.postgresql.org/message-id/cadupchw1pomsunonmdvawltq-a3x_a3zqmusjhs4rcexipg...@mail.gmail.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
