Return-Path: X-Original-To: apmail-beam-commits-archive@minotaur.apache.org Delivered-To: apmail-beam-commits-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id D428719A15 for ; Tue, 5 Apr 2016 04:21:27 +0000 (UTC) Received: (qmail 40728 invoked by uid 500); 5 Apr 2016 04:21:27 -0000 Delivered-To: apmail-beam-commits-archive@beam.apache.org Received: (qmail 40684 invoked by uid 500); 5 Apr 2016 04:21:27 -0000 Mailing-List: contact commits-help@beam.incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@beam.incubator.apache.org Delivered-To: mailing list commits@beam.incubator.apache.org Received: (qmail 40675 invoked by uid 99); 5 Apr 2016 04:21:27 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd2-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 05 Apr 2016 04:21:27 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd2-us-west.apache.org (ASF Mail Server at spamd2-us-west.apache.org) with ESMTP id 098FC1A070B for ; Tue, 5 Apr 2016 04:21:27 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd2-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -4.021 X-Spam-Level: X-Spam-Status: No, score=-4.021 tagged_above=-999 required=6.31 tests=[KAM_LAZY_DOMAIN_SECURITY=1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RP_MATCHES_RCVD=-0.001] autolearn=disabled Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd2-us-west.apache.org [10.40.0.9]) (amavisd-new, port 10024) with ESMTP id ORdBS4Sk9Aqo for ; Tue, 5 Apr 2016 04:21:26 +0000 (UTC) Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with SMTP id 4EA3F5FAF4 for ; Tue, 5 Apr 2016 04:21:26 +0000 (UTC) Received: (qmail 40424 invoked by uid 99); 5 Apr 2016 04:21:25 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 05 Apr 2016 04:21:25 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id 9CF2E2C14F6 for ; Tue, 5 Apr 2016 04:21:25 +0000 (UTC) Date: Tue, 5 Apr 2016 04:21:25 +0000 (UTC) From: "Kenneth Knowles (JIRA)" To: commits@beam.incubator.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (BEAM-170) Session windows should not be identified by their bounds MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/BEAM-170?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15225660#comment-15225660 ] Kenneth Knowles commented on BEAM-170: -------------------------------------- Yes, even key+start+end is not enough. Updating the description. > Session windows should not be identified by their bounds > -------------------------------------------------------- > > Key: BEAM-170 > URL: https://issues.apache.org/jira/browse/BEAM-170 > Project: Beam > Issue Type: Bug > Reporter: Kenneth Knowles > > Today, if two session windows have the same bounds, they are considered the same window. This is an accident. It is not intended that any session windows are considered equal except via the operation of merging them into the same session. > A risk associated with this behavior is that two windows that happen to coincide will share per-window-and-key state rather than evolving separately and having their separate state reconciled by state merging logic. These code paths are not required to be coherent, and in practice they are not. > In particular, if the trigger for a session window ever finishes, then subsequent data in a window with the same bounds will be dropped, whereas if it had differed by a millisecond it would have created a new session, ignoring the previously closed session. -- This message was sent by Atlassian JIRA (v6.3.4#6332)