Marcel Kornacker has posted comments on this change. Change subject: IMPALA-4623: Enable file handle cache ......................................................................
Patch Set 4: (8 comments) http://gerrit.cloudera.org:8080/#/c/6478/4/be/src/runtime/disk-io-mgr.cc File be/src/runtime/disk-io-mgr.cc: Line 1309: string key = string(fname) + ":" + std::to_string(mtime); you can get rid of dealing with strings here (and doing a bunch of allocations) entirely by using something out of util/hash-util.h to compute the hash on fname and mtime separately (no need to convert it to a string). Line 1315: // Get lock that's obvious, no need to paraphrase a single statement (unless there's something subtle going on). Line 1318: // Look up in the multimap (find range of values for key) same here Line 1326: if (!elem->reference_count_) { use explicit numeric comparisons, this isn't a bool (although maybe it should be). Line 1331: ImpaladMetrics::IO_MGR_NUM_CACHED_FILE_HANDLES->Increment(-1L); hm, i'm not sure we should do that. it's still a cached file handle. Line 1395: if (p.size_ > p.capacity_) { single line http://gerrit.cloudera.org:8080/#/c/6478/4/be/src/runtime/disk-io-mgr.h File be/src/runtime/disk-io-mgr.h: Line 273: : fh_(fh), reference_count_(0) {} single line Line 276: int reference_count_; why refcount instead of just 'bool in_use' or something like that? -- To view, visit http://gerrit.cloudera.org:8080/6478 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: Ibe5ff60971dd653c3b6a0e13928cfa9fc59d078d Gerrit-PatchSet: 4 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Joe McDonnell <joemcdonn...@cloudera.com> Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Joe McDonnell <joemcdonn...@cloudera.com> Gerrit-Reviewer: Marcel Kornacker <mar...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-HasComments: Yes
