Tim Armstrong has posted comments on this change. Change subject: IMPALA-5347: Parquet scanner microoptimizations ......................................................................
Patch Set 5: (2 comments) http://gerrit.cloudera.org:8080/#/c/6950/5/be/src/exec/parquet-column-readers.cc File be/src/exec/parquet-column-readers.cc: Line 315: /// Use __restrict__ so that the compiler knows that it is safe to cache member > Just so I'm clear: We compile with -fno-strict-alias so there's no type-based alias analysis at all - basically anything can alias. ParquetLevelDecoder::cached_levels_ is also a problem. I expanded the comment to be less hand-wavy. Line 489: uint8_t val_buf[sizeof(T)]; > Also needs aligning as T, right? Seems like a good idea. I'm not sure if we really depend on it - generally we don't assume that Tuples are actually aligned. -- To view, visit http://gerrit.cloudera.org:8080/6950 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I49ec523a65542fdbabd53fbcc4a8901d769e5cd5 Gerrit-PatchSet: 5 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Tim Armstrong <[email protected]> Gerrit-Reviewer: Alex Behm <[email protected]> Gerrit-Reviewer: Jim Apple <[email protected]> Gerrit-Reviewer: Mostafa Mokhtar <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: anujphadke <[email protected]> Gerrit-HasComments: Yes
