Mailing-List: contact derby-dev-help@db.apache.org; run by ezmlm
Precedence: bulk
Reply-To: <derby-dev@db.apache.org>
Received-SPF: pass (asf.osuosl.org: domain of suresh.thalamati@gmail.com
 designates 64.233.162.205 as permitted sender)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
        s=beta; d=gmail.com;
        h=received:message-id:date:from:user-agent:x-accept-language:mime-version:to:subject:references:in-reply-to:content-type:content-transfer-encoding;
        b=DgxGgdxKzy36/oU+5UpQE9/oUMBAVbHqJ5FFaF2OfJWejl/81uWn9uf7KJiC+IIlU32blDUtC0aSNeyuieimrLfVVmrHOgWRTBqpS7rxDpq/Dr3zEG4/leyz2PzQO84DZaqLQn0UG+Jo00+EhH2uD4M609nZCrl15fDTwuhPdMA=
Message-ID: <4422E6A4.8060002@gmail.com>
Date: Thu, 23 Mar 2006 10:19:16 -0800
From: Suresh Thalamati <suresh.thalamati@gmail.com>
User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206)
MIME-Version: 1.0
To: derby-dev@db.apache.org
Subject: Re: What difference between containCache and pageCache?
References: <BAY113-F10FAB61F63BD3550FE2A7A9ADE0@phx.gbl>
In-Reply-To: <BAY113-F10FAB61F63BD3550FE2A7A9ADE0@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit

Container cache is used to keep track of the open containers 
(table/indexes). An item in this cache is considered is dirty , if 
the container header is modified or a dirty page from the cache is 
written to the container file.

At checkpoint, page cache cleaning make sure all dirty pages in the 
page cache are written to the disk and the container cache cleaning 
will write the header and sync the container file if it is a dirty 
container.

Thanks
-suresh


Raymond Raymond wrote:
> Thanks for your answer. I am looking at the code about checkpoint.
> I found, in checkpoint, both of containerCache and pageCache will
> dump dirty pages. As your answer, does it mean the dirty pages in
> containerCache indicate updates on tables or indexes, and the dirty
> pages in pageCache indicate updates on rows? Am I right?
> 
> Thanks.
> 
> Raymond
> 
> 
>> From: Bryan Pendleton <bpendleton@amberpoint.com>
>>
>> Raymond Raymond wrote:
>>
>>> I found these two kinds of cache manager in the source
>>> code. I am not sure what difference between containerCache
>>> and pageCache?
>>
>>
>> A container is an aggregate object like a table or an index.
>>
>> A page is a hunk of bytes inside a container, used for storing rows.
>>
>> Does that help?
>>
>> thanks,
>>
>> bryan
>>
> 
> _________________________________________________________________
> Powerful Parental Controls Let your child discover the best the Internet 
> has to offer. 
> http://join.msn.com/?pgmarket=en-ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Market_MSNIS_Taglines 
>  Start enjoying all the benefits of MSN� Premium right now and get the 
> first two months FREE*.
> 
>