From commits-return-11999-archive-asf-public=cust-asf.ponee.io@pulsar.incubator.apache.org Mon Jul 30 08:02:58 2018 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 450E5180630 for ; Mon, 30 Jul 2018 08:02:58 +0200 (CEST) Received: (qmail 95731 invoked by uid 500); 30 Jul 2018 06:02:57 -0000 Mailing-List: contact commits-help@pulsar.incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@pulsar.incubator.apache.org Delivered-To: mailing list commits@pulsar.incubator.apache.org Received: (qmail 95722 invoked by uid 99); 30 Jul 2018 06:02:57 -0000 Received: from ec2-52-202-80-70.compute-1.amazonaws.com (HELO gitbox.apache.org) (52.202.80.70) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 30 Jul 2018 06:02:57 +0000 From: GitBox To: commits@pulsar.apache.org Subject: [GitHub] ratcashdev edited a comment on issue #1334: Experimental settings to achieve 5 ms latency Message-ID: <153293057652.27510.6180652681478866156.gitbox@gitbox.apache.org> Date: Mon, 30 Jul 2018 06:02:56 -0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit ratcashdev edited a comment on issue #1334: Experimental settings to achieve 5 ms latency URL: https://github.com/apache/incubator-pulsar/issues/1334#issuecomment-408586469 Thank you for the detailed explanation, @sijie. So if I understand all of that correctly, 1. when we compare the two in their default configuration (default config being the `apple`), Kafka will probably have lower latency than Pulsar for publishing, since - at least up until know - it could not control fsync behavior. Users need to keep in mind the difference in behaviour at their default settings: `filesystem-persistence` (Kafka) vs `direct-to-disk-persistence` and forced fsync (Pulsar) 2. when we compare the two in a config that's comparable in behavior (here identical behavior being the `apple`), Kafka (with some extra settings getting it closer to `direct-to-disk-persistence`) will likely provide higher latency compared to Pulsar (with its default setting in this regard). 3. Pulsar using `filesystem-persistence` was not possible up until recently (can you please pinpoint the exact config that needs to be tweaked?) , and it's likely that it will provide lower latencies, but not lower than with a `non-persistent` topic, will it? And yet back to option No 2 above: Kafka , by default, (first?) replicates the data, then writes to the filesystem. What's the order for Pulsar, when we disable forced fsync (and also when its on)? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: users@infra.apache.org With regards, Apache Git Services