Marcel Kornacker has posted comments on this change. Change subject: IMPALA-3201: reservation implementation for new buffer pool ......................................................................
Patch Set 4: (8 comments) http://gerrit.cloudera.org:8080/#/c/3993/4/be/src/bufferpool/reservation-tracker.h File be/src/bufferpool/reservation-tracker.h: Line 50: /// * A tracker's reservation is at most its reservation limit. does 'reservation' mean 'remaining reservation' or 'what has been deducted from reservation'? i find the former more intuitive (as in "i reserved a total of 10gb and now have 6gb left of my reservation; i deducted 4gb since i obtained my initial reservation"). Line 51: /// * A tracker's reservation is at least the sum of its childrens' reservations plus however, that would contradict this sentence (because my children eat into what is left of my reservation). Line 59: /// as consumption because reserved memory is committed. An existing reservation can we need to be careful to differentiate actual consumption vs. used-up reservation for a running query (because a discrepancy is interesting from a diagnostic perspective) Line 60: /// therefore always be used without increasing consumption and with no risk of exceeding this seems to contradict what you said earlier. Line 70: void InitRootTracker(MemTracker* mem_tracker, int64_t reservation); could the root be expressed as having parent == null? Line 74: /// children will be counted as consumption against 'mem_tracker'. if the reservation is really counted immediately against a memtracker (without actual memory being allocated), doesn't that make the memtracker semantically simply a reservation tracker? Line 103: /// Increase the usage. The tracker must have at least 'amount' remaining in its i find this terminology confusing, as explained above. do you really mean 'limit' by 'reservation'? Line 118: int64_t GetUsage(); i find this term ambiguous as well, because it seems to imply the memory is actively being used (which the reservation tracker shouldn't be concerned with). -- To view, visit http://gerrit.cloudera.org:8080/3993 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I35cc89e863efb4cc506657bfdaaaf633a10bbab6 Gerrit-PatchSet: 4 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Tim Armstrong <[email protected]> Gerrit-Reviewer: Dan Hecht <[email protected]> Gerrit-Reviewer: Marcel Kornacker <[email protected]> Gerrit-Reviewer: Michael Ho Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-HasComments: Yes
