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<DIV><FONT face=Arial size=2>Woops - please
ignore. I just saw the article references
you provided at the bottom of your first
email.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- K</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Bryan-</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Do you have
a paper describing the DBCache system?
If so, please post to the list - it would
be a good reference to have.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Sorry I've been
so quiet lately - our business has been insanely
busy...</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>thanks!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- K</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> </FONT>
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<TD><FONT face=Arial size=2><FONT color=red>>
Alex,<BR><BR>I think that we should develop
some I/O performance tests that we<BR>can
use to characterize jdbm in its 1.x and 2.x
forms and support<BR>performance tuning.
Our own application benchmark is actually
CPU<BR>bound (it performs inference during
RDFS data loading and makes<BR>heavy use
of the object cache). In contrast,
I believe that you have<BR>mentioned that
your applications tend to be I/O bound. It
would be<BR>good to identify some suiteable
ways of measuring I/O read/write <BR>throughput
for these purposes.<BR><BR>One interesting
feature of DBCache is that the safe is relatively
small,<BR>even for very large databases,
and could be placed onto a solid state<BR>disk
with very low latency random writes :-)<BR><BR>-bryan<BR><BR>-----Original
Message-----<BR>From: <A href="mailto:jdbm-developer-admin@...
color=#0000ff>jdbm-developer-admin@...
href="mailto:jdbm-developer-admin@...
color=#0000ff>[mailto:jdbm-developer-admin@...>
On Behalf Of Thompson,<BR>Bryan B.<BR>Sent:
Tuesday, January 10, 2006 6:40 AM<BR>To:
Alex Boisvert<BR>Cc: <A href="mailto:jdbm-developer@...
color=#0000ff>'jdbm-developer@...:
RE: [Jdbm-developer] Track-based logging<BR><BR><BR>Alex,<BR><BR>The
article that I am thinking of required an
algorithm which could predict<BR>the state
of the disk, which I think could be done
in Java. While I have<BR>not read deeply
into what is required, I am not convinced
that Java I/O <BR>would be a bottleneck.
If the missing feature is the ability
to address the<BR>disk in terms of tracks
or to use a special format for the disk,
then I<BR>would certainly agree. However
I was thinking more in terms of a plugin
for<BR>track-based logging. Likewise,
we could use a plugin to permit a native<BR>file
system, thereby avoiding the logical to physical
disk address<BR>translation.<BR><BR>There
are three logging requirements for DBCache.
The primary database can<BR>be written
using a track at a time method if it is divided
into segments and<BR>each segment is read
or written using track-based techniques.
The cache<BR>(safe)<BR>for DBCache
might not be amenable to track-based logging
since I seem to<BR>recall that writes to
the safe do not have sufficient contiguous
length to<BR>make this a interesting technique.
Likewise, writes back to the main<BR>database
during long transactions would not benefit
from this techique.<BR>However, writes on
a backup media might well benefit since the
strategy for<BR>media recovery required append
only semantics.<BR><BR>All of the proceeding
is from memory. It's been several months
since I read<BR>these articles -- I am just
digging out my copies now.<BR><BR>-bryan<BR><BR>-----Original
Message-----<BR>From: Alex Boisvert <A href="mailto:boisvert@...
color=#0000ff>[mailto:boisvert@...>
<BR>Sent: Monday, January 09, 2006 3:37 PM<BR>To:
Thompson, Bryan B.<BR>Cc: <A href="mailto:jdbm-developer@...
color=#0000ff>'jdbm-developer@...:
Re: [Jdbm-developer] Track-based logging<BR><BR><BR><BR>Bryan,<BR><BR>I've
done some reading on track-based logging
and it was not entirely <BR>clear to me that
it would be possible in "Pure Java", without
relying on <BR>some underlying native code,
either C/C++ through JNDI or a special <BR>operating
system driver.<BR><BR>Do you see how it could
be implemented in pure Java?<BR><BR>alex<BR><BR><BR>Thompson,
Bryan B. wrote:<BR>> Excellent! Along
similar lines, there has been some interesting
work<BR>> recently on track-based logging.
I will dig up some references as I
<BR>> get going.<BR>> <BR>> -bryan<BR><BR><BR>-------------------------------------------------------<BR>This
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