From zookeeper-user-return-2353-apmail-hadoop-zookeeper-user-archive=hadoop.apache.org@hadoop.apache.org Fri Oct 22 05:22:44 2010 Return-Path: Delivered-To: apmail-hadoop-zookeeper-user-archive@minotaur.apache.org Received: (qmail 88827 invoked from network); 22 Oct 2010 05:22:43 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 22 Oct 2010 05:22:43 -0000 Received: (qmail 46741 invoked by uid 500); 22 Oct 2010 05:22:43 -0000 Delivered-To: apmail-hadoop-zookeeper-user-archive@hadoop.apache.org Received: (qmail 46401 invoked by uid 500); 22 Oct 2010 05:22:40 -0000 Mailing-List: contact zookeeper-user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: zookeeper-user@hadoop.apache.org Delivered-To: mailing list zookeeper-user@hadoop.apache.org Received: (qmail 46392 invoked by uid 99); 22 Oct 2010 05:22:39 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 22 Oct 2010 05:22:39 +0000 X-ASF-Spam-Status: No, hits=0.0 required=10.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [68.142.207.71] (HELO web31808.mail.mud.yahoo.com) (68.142.207.71) by apache.org (qpsmtpd/0.29) with SMTP; Fri, 22 Oct 2010 05:22:30 +0000 Received: (qmail 95939 invoked by uid 60001); 22 Oct 2010 05:22:08 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1287724928; bh=fTApevfDZUfYSEHc84osncamU0uI3LXtA/7PZYkvdX0=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=SAQNPae8M2DK4XmSpZF/e7wJUfQ5qEvNYQOv7/nQpRSzF2zhV9vuOb+YtpHgaBWAi6WZ2efElZo4XBqpwzNKuDFMNQKUmVoKE89z3TS/KbkLQ964fD3KLXXVOjhLox/RQ7cluTzUYHMrWEJRulQvtu/BlD5FF0qs+SIJGiTWazY= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=oxVHfU3GrPgSWXlAaYCv/K5EHYJbzj7LPkTnCFIug1gp5woqEOwWdhYAoEWSpIOQKSwggNdHG7aAyQ64imie9cuUKmJtSGI1Nprqgyl8wDOCCl3dG54i9zm+sg9B4dkostBOB5Hw+9D9fUpjT0tmqp6K7Oj29higZfd7kBLrts8=; Message-ID: <767576.95500.qm@web31808.mail.mud.yahoo.com> X-YMail-OSG: lqNaqMEVM1kLRXpM4s99ckHlWfPmqB.hQCmtxI8gD3A3c6v iC7haP6rNHfP3iLruLujKMP7xahmq6dX_7Sgg0Jsxdq1Zf7RuxmSKcYtPEn3 dTGS1gB..mP.5v2LPvUk2HgtKEIeKQrCbmqT1LFPplLj1QXJfMdkzoPv6buY YMiGCXvqPZjgs90gWobxgxUhibm4eRIWx4IK8KhNRlp50ztc8BcXCAXEnvc9 QAcj1J2f3T4yYxR6qNhjmaXQaqWqAMqgZ1nJKwc7zZRDYKQjShMK7E1Zyh_9 ZmWzLohlp1E6ea8a_Hs16mxFdgExqqTlhyE3ztenTVCrFSYXYUgtLVg-- Received: from [59.163.89.69] by web31808.mail.mud.yahoo.com via HTTP; Thu, 21 Oct 2010 22:22:08 PDT X-Mailer: YahooMailRC/504.5 YahooMailWebService/0.8.107.285259 Date: Thu, 21 Oct 2010 22:22:08 -0700 (PDT) From: amit jaiswal Subject: Is it possible to read/write a ledger concurrently To: Zookeeper User MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org Hi,=0A=0AIn BookKeeper documentation, the sample program creates a ledger, = writes some =0Aentries and then *closes* the ledger. Then a client program = opens the ledger, =0Aand reads the entries from it.=0A=0AIs it possible for= program1 to write to a ledger, and program2 to read from the =0Aledger at = the same time. In BookKeeper code, if a client tries to read from a =0Aledg= er which is not being closed (as per its metadata in zk), then a recovery = =0Aprocess is started to check for consistency.=0A=0AWaiting for ledger to = get closed can introduce lot of latency at the client =0Aside. Can somebody= explain this functionality?=0A=0A-regards=0AAmit