Mailing-List: contact users-help@activemq.apache.org; run by ezmlm
Precedence: bulk
Reply-To: users@activemq.apache.org
Received-SPF: pass (nike.apache.org: domain of gary.tully@gmail.com designates
 209.85.216.43 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :content-type:content-transfer-encoding;
        b=iTnY0R47xDW3oibBjtwOW7oI2Zx5jyV91TB53zWTUmZWcb7Gc2UWQLt+BLlt2ll2KN
         J+X9n23csNlD17o9Oul2gN4j5z1gC/S8A+WcSDKkeoAr5gq4w9zZw61WxEPyLTanzriK
         bkEspgEnIYa4plOdZjwSjAnIiKeLiuYweKN0Q=
MIME-Version: 1.0
In-Reply-To: <m3pqtc9xpv.fsf@alex.2e-systems.com>
References: <m3pqtc9xpv.fsf@alex.2e-systems.com>
Date: Wed, 8 Dec 2010 15:24:00 +0000
Message-ID: <AANLkTi=Uuwn4ryMj1T4hPMS5SEOdKEdu+bNzxf3dEzhh@mail.gmail.com>
Subject: Re: KahaDB latch wait warnings
From: Gary Tully <gary.tully@gmail.com>
To: users@activemq.apache.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

In the main, it is not important, that should be at debug or trace
level logging or removed altogether, it is just an indication of the
pagefile sync to disk latency and the amount of concurrent writes that
are pending at the time, an remnant of some performance tuning work
that was done for 5.4.0. the 100ms limit is arbitrary.
Do u mind tracking this with a jira issue as it will probably come up again=
.

On 8 December 2010 13:54, Aleksandar Ivanisevic
<aleksandar@ivanisevic.de> wrote:
>
>
> Just switched to kahadb on my amq 5.4.1 (fuse) and the log is filling
> with this:
>
>
> 2010-12-08 14:26:12,668 | WARN =A0| KahaDB PageFile flush: 3 queued write=
s, latch wait took 119 | org.apache.kahadb.page.PageFile | ActiveMQ Journal=
 Checkpoint Worker
> 2010-12-08 14:28:03,769 | WARN =A0| KahaDB PageFile flush: 7 queued write=
s, latch wait took 140 | org.apache.kahadb.page.PageFile | ActiveMQ Journal=
 Checkpoint Worker
> 2010-12-08 14:28:39,125 | WARN =A0| KahaDB PageFile flush: 3 queued write=
s, latch wait took 112 | org.apache.kahadb.page.PageFile | ActiveMQ Journal=
 Checkpoint Worker
> 2010-12-08 14:30:04,928 | WARN =A0| KahaDB PageFile flush: 8 queued write=
s, latch wait took 109 | org.apache.kahadb.page.PageFile | ActiveMQ Journal=
 Checkpoint Worker
> 2010-12-08 14:30:28,788 | WARN =A0| KahaDB PageFile flush: 8 queued write=
s, latch wait took 18839 | org.apache.kahadb.page.PageFile | ActiveMQ Journ=
al Checkpoint Worker
>
> quick code search turns out that this warning is fixed to 100ms
>
> http://bit.ly/gYH1Zu
>
> why 100ms and why is this important?
>
>
>


--=20
http://blog.garytully.com
http://fusesource.com