Joe McDonnell has posted comments on this change. ( http://gerrit.cloudera.org:8080/14406 )
Change subject: IMPALA-9033: log on slow HDFS I/Os ...................................................................... Patch Set 1: (1 comment) This is useful, one comment. http://gerrit.cloudera.org:8080/#/c/14406/1/be/src/runtime/io/hdfs-file-reader.cc File be/src/runtime/io/hdfs-file-reader.cc: http://gerrit.cloudera.org:8080/#/c/14406/1/be/src/runtime/io/hdfs-file-reader.cc@178 PS1, Line 178: // Log diagnostics : int64_t elapsed_time = req_context_read_timer.ElapsedTime(); : bool is_slow_read = elapsed_time : > FLAGS_fs_slow_read_log_threshold_ms * NANOS_PER_MICRO * MICROS_PER_MILLI; : if (is_slow_read) { : LOG(INFO) << "Slow FS I/O operation on " << *scan_range_->file_string() << " for " : << "instance " << PrintId(scan_range_->reader_->instance_id()) : << " of query " << PrintId(scan_range_->reader_->query_id()) << ". " : << "Last read returned " : << PrettyPrinter::PrintBytes(current_bytes_read) << ". " : << "This thread has read " << PrettyPrinter::PrintBytes(*bytes_read) : << "/" << PrettyPrinter::PrintBytes(bytes_to_read) : << " starting at offset " << file_offset << " in this I/O scheduling " : << "quantum."; : } One thought: If an IO took a long time and then failed, it would be nice to get this message. I think we could move this up just above the "if (!status.ok())" with a few minor modifications. There is a bit of inexactness in that the time we are reporting might come from multiple hdfs calls, either because of a retry or because of the while loop. I think that is fine; this is useful on its own. -- To view, visit http://gerrit.cloudera.org:8080/14406 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I1929921495706b482d91d91cffe27bee4478f5c4 Gerrit-Change-Number: 14406 Gerrit-PatchSet: 1 Gerrit-Owner: Tim Armstrong <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Joe McDonnell <[email protected]> Gerrit-Reviewer: Tamas Mate <[email protected]> Gerrit-Comment-Date: Thu, 10 Oct 2019 18:10:22 +0000 Gerrit-HasComments: Yes
