Yeah, that's pretty much where I'm going. -Sam On Fri, Dec 9, 2016 at 3:24 PM, Sage Weil <sweil@xxxxxxxxxx> wrote: > On Fri, 9 Dec 2016, Samuel Just wrote: >> Currently, never. However, I'm thinking that we might want to retain >> the freedom to not send the structure if it's really big. And >> actually, we won't ever need to extend a received past_intervals >> structure to the current epoch since if the interval changed, we'd >> throw out the whole message. > > I'd say throw out the incremental build code, then, and assert > past_intervals is present at notify time; we can re-add something to > recalculate the whole past_intervals if it becomes necessary in the > future. > > sage > > >> -Sam >> >> On Fri, Dec 9, 2016 at 2:16 PM, Sage Weil <sweil@xxxxxxxxxx> wrote: >> > On Fri, 9 Dec 2016, Samuel Just wrote: >> >> In particular, we don't need PG::generate_past_intervals duplicating >> >> the logic in build_past_intervals_parallel since constructed PG >> >> objects only ever need to maintain a consistent past_intervals >> >> structure, never build it from scratch. >> > >> > Sounds good to me. >> > >> > My main question is: >> > >> >> On Fri, Dec 9, 2016 at 11:59 AM, Samuel Just <sjust@xxxxxxxxxx> wrote: >> >> > There's code for dealing with some odd past_intervals configurations >> >> > including doesn't go back far enough and doesn't go forward far >> >> > enough. I *think* we can simplify this as follows: >> >> > 1) Once the PG object is constructed and in memory, past_intervals >> >> > extends from history.last_epoch_started to the PG's current map >> >> > 2) On disk, either 1) is true or the set is empty (after an import) >> >> > >> >> > On boot, the OSD generates past_intervals in parallel for any PGs >> >> > without them (and perhaps verifies 1) for the rest). On receipt of a >> >> > Notify creating a PG, the OSD generates the past_intervals structure >> >> > before instantiating the PG using the same process as on boot -- >> >> > starting with the included past_intervals if present (may not extend >> >> > to the current map, and so may need to be extended). >> > >> > When does this actually happen? If PGs are always in state 1, can we >> > instead ensure that PG notify will always include past_intervals and that >> > a received notify will never require us to go off do the (slow) work of >> > loading up old maps to generate old intervals? >> > >> > Then, we can focus our efforts on make the past_intervals representation >> > compact (e.g., by discarding redundant intervals)... >> > >> > sage >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
