[ https://issues.apache.org/jira/browse/TEZ-4075?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17249859#comment-17249859 ]
Jonathan Turner Eagles commented on TEZ-4075: --------------------------------------------- [~glapark], please open an apache jira and we can address this issue. > Tez: Reimplement tez.runtime.transfer.data-via-events.enabled > ------------------------------------------------------------- > > Key: TEZ-4075 > URL: https://issues.apache.org/jira/browse/TEZ-4075 > Project: Apache Tez > Issue Type: Improvement > Reporter: Gopal Vijayaraghavan > Assignee: Richard Zhang > Priority: Major > Fix For: 0.10.0 > > Attachments: TEZ-4075.10.patch, TEZ-4075.15.patch, TEZ-4075.16.patch, > TEZ-4075.enable-dme.16.patch, Tez-4075.5.patch, Tez-4075.8.patch > > Time Spent: 50m > Remaining Estimate: 0h > > This was factored out by TEZ-2196, which does skip buffers for 1-partition > data exchanges (therefore goes to disk directly). > {code} > if (shufflePayload.hasData()) { > shuffleManager.addKnownInput(shufflePayload.getHost(), > DataProto dataProto = shufflePayload.getData(); > shufflePayload.getPort(), srcAttemptIdentifier, srcIndex); > FetchedInput fetchedInput = > inputAllocator.allocate(dataProto.getRawLength(), > dataProto.getCompressedLength(), srcAttemptIdentifier); > moveDataToFetchedInput(dataProto, fetchedInput, hostIdentifier); > shuffleManager.addCompletedInputWithData(srcAttemptIdentifier, > fetchedInput); > } else { > shuffleManager.addKnownInput(shufflePayload.getHost(), > shufflePayload.getPort(), srcAttemptIdentifier, srcIndex); > } > {code} > got removed in > https://github.com/apache/tez/commit/1ba1f927c16a1d7c273b6cd1a8553e5269d1541a > It would be better to buffer up the 512Byte limit for the event size before > writing to disk, since creating a new file always incurs disk traffic, even > if the file is eventually being served out of the buffer cache. > The total overhead of receiving an event, then firing an HTTP call to fetch > the data etc adds approx 100-150ms to a query - the data xfer through the > event will skip the disk entirely for this & also remove the extra IOPS > incurred. > This channel is not suitable for large-scale event transport, but > specifically the workload here deals with 1-row control tables which consume > more bandwidth with HTTP headers and hostnames than the 93 byte payload. -- This message was sent by Atlassian Jira (v8.3.4#803005)