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From "Raymond Raymond" <raymond_de...@hotmail.com>
Subject Re: Re: Can anyone give me some suggestions?
Date Mon, 22 Aug 2005 18:11:48 GMT


>From: Mike Matrigali <mikem_app@sbcglobal.net>
>Reply-To: "Derby Development" <derby-dev@db.apache.org>
>
>Could you define "fuzzy" checkpoint or site what update interference
>you are trying to avoid.
>

Fuzzy checkpointing means checkpoints are asynchronous and occur ant the
same time as new database updates are being made. The general actions
in a fuzzy checkpoint are:
1. Force log buffer to disk from memory.
2. To check if there are any buffer still on the checkpoint list form the 
previous checkpoint.
    If there are any, then write them out to disk.(the list is supposed to 
be empty under
    some control).
3. All dirty buffers will be listed in the current checkpoint list.
4. Gather other useful information.
Once these actions have done, the remainder of the checkpoint can also 
proceed in
parallel with future database updates. e.t.: a write process will examine 
the checkpoint
list periodically, write some of the buffers on the list to disk and remove 
thme from the
list.Under some controls, it is supposed that the list will be empty just 
befor the next
checkpoint is taken.

Those are just the general processes of fuzzy checkpointing. I think we can 
use some
technic to make it works more efficient. That is what I am trying to do.^_^.
Anyone has some ideas about that?




Raymond

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