* Amit Langote (langote_amit...@lab.ntt.co.jp) wrote: > 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?
As I recall, it didn't, and further, modern filesystems are pretty good
about avoiding fragmentation anyway..
I'm not saying Jim's completely off-base with this idea, I'm just not
sure that it'll really buy us much.
Thanks,
Stephen
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