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Subject: Re: [Opensim-users] bin/OpenSim.db-journal file begin written and deleted many times
From: Dahlia Trimble <dahliatrimble () gmail ! com>
Date: 2014-04-29 11:10:57
Message-ID: CAAQTD4XTv2Ah4jSdbALLqc3LvV1phTVWA-t8S5PfERLP3Ezf0A () mail ! gmail ! com
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That long shut down has really nothing to do with the translate scene
command and everything to do with using Sqlite on a high object-density
region where a lot of objects had changed. Sqlite has been extremely slow
as long as I've used OpenSim, so I don't believe it's a new issue. I'm not
sure of the meaning of the journal file but it's name suggests it may be
doing some transaction journaling which can be deleted after a transaction
is complete. I'm also not that familiar with the database layers in OpenSim
but I'd think that if it was using transactions it would be a good thing as
they can protect database integrity in the case of a crash or other failure
during an update.
I use Sqlite for some high-prim regions and it's horribly slow. I just use
the "backup" command while the region is still running so it can persist
while the region is in use. Either that, or I tell it to shutdown and then
go out for a walk or something.
On Tue, Apr 29, 2014 at 3:33 AM, Ai Austin <ai.ai.austin@gmail.com> wrote:
> Gwyneth wrote:
>
>> What version are you using, Ai? I have seen a fluctuation of viewer-side
>> FPS on an apparently 'empty' region, usually a signal that there is some
>> 'invisible' back-end processing at the simulator level, but haven't been
>> able to track it down to anything yet. Selecting a lot of prims and
>> linking
>> them together now takes quite a lot of time (sometimes even a minute or
>> so!). This is on 0.8.0 Dev 722f030. I suspected some delays while writing
>> to the database, and having some sort of database journal being written to
>> a lot of times would certainly account for that!
>>
>
> I was using the OSGrid latest add-on region release from a few days ago
> (r/24670) Gwyneth.
>
> Dahlia wrote:
>
>> Translate scene should complete quite quickly, all it does is move the
>> objects in the scene. What you are probably seeing is the changes being
>> saved to the database, an entirely different process. If you are using
>> Sqlite for your region database than storing changes to the scene will
>> always be quite slow. It would likely take just as long for loading an oar
>> with the same number of objects and saving them to the database. If you
>> need faster region storage, try using one of the other database options
>> such as mysql.#
>>
>
>
> That's right Dahlia. The translate scene on 600 or so objects was
> essentially instant and I was able to move the avatar about (using ODE
> temporarily until Robert's r/24672 commit is in the OSGrid release) in the
> new negative Z underwater area fine. It was indeed as I did the
> shutdown... and I did assume it was the persisting to data base part.. that
> took nearly 30 minutes. It was SQLite for the add on regions we have for
> experiments.. not our MySQL usual data base. But still.. constantly
> creating and deleting the db-journal file (perhaps once per DB write?) MUST
> make this persisting process slower than needed? I also thought I better
> make sure the persisting process completed even though it as taking ages or
> else there may have been only a partial translation. If I had not had the
> opensim\bin window open I would have thought the OpenSim.exe console was
> jammed and stopped wit with the X on the console window... I assume that
> would NOT have been good, so it could be a source fo problems if persisting
> objects takes so long. A better indication of progress might be to put a
> dot out every 50 or 100 objects persisted on the console to remind the user
> the region OpenSim.exe still need time to complete.
>
>
>
>
>
> _______________________________________________
> Opensim-users mailing list
> Opensim-users@opensimulator.org
> http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-users
>
[Attachment #5 (text/html)]
<div dir="ltr"><div>That long shut down has really nothing to do with the translate \
scene command and everything to do with using Sqlite on a high object-density region \
where a lot of objects had changed. Sqlite has been extremely slow as long as \
I've used OpenSim, so I don't believe it's a new issue. I'm not sure \
of the meaning of the journal file but it's name suggests it may be doing some \
transaction journaling which can be deleted after a transaction is complete. I'm \
also not that familiar with the database layers in OpenSim but I'd think that if \
it was using transactions it would be a good thing as they can protect database \
integrity in the case of a crash or other failure during an update.<br> <br></div>I \
use Sqlite for some high-prim regions and it's horribly slow. I just use the \
"backup" command while the region is still running so it can persist while \
the region is in use. Either that, or I tell it to shutdown and then go out for a \
walk or something.<br> </div><div class="gmail_extra"><br><br><div \
class="gmail_quote">On Tue, Apr 29, 2014 at 3:33 AM, Ai Austin <span dir="ltr"><<a \
href="mailto:ai.ai.austin@gmail.com" \
target="_blank">ai.ai.austin@gmail.com</a>></span> wrote:<br> <blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"><div class="">Gwyneth wrote:<br> <blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"> What version are you using, Ai? I have seen a fluctuation of \
viewer-side<br> FPS on an apparently 'empty' region, usually a signal that \
there is some<br> 'invisible' back-end processing at the simulator level, but \
haven't been<br> able to track it down to anything yet. Selecting a lot of prims \
and linking<br> them together now takes quite a lot of time (sometimes even a minute \
or<br> so!). This is on 0.8.0 Dev 722f030. I suspected some delays while writing<br>
to the database, and having some sort of database journal being written to<br>
a lot of times would certainly account for that!<br>
</blockquote>
<br></div>
I was using the OSGrid latest add-on region release from a few days ago (r/24670) \
Gwyneth.<br> <br>
Dahlia wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"><div class=""> Translate scene should complete quite quickly, \
all it does is move the<br> objects in the scene. What you are probably seeing is the \
changes being<br> saved to the database, an entirely different process. If you are \
using<br> Sqlite for your region database than storing changes to the scene will<br>
always be quite slow. It would likely take just as long for loading an oar<br>
with the same number of objects and saving them to the database. If you<br>
need faster region storage, try using one of the other database options<br></div>
such as mysql.#<br>
</blockquote>
<br>
<br>
That's right Dahlia. The translate scene on 600 or so objects was essentially \
instant and I was able to move the avatar about (using ODE temporarily until \
Robert's r/24672 commit is in the OSGrid release) in the new negative Z \
underwater area fine. It was indeed as I did the shutdown... and I did assume it \
was the persisting to data base part.. that took nearly 30 minutes. It was SQLite \
for the add on regions we have for experiments.. not our MySQL usual data base. But \
still.. constantly creating and deleting the db-journal file (perhaps once per DB \
write?) MUST make this persisting process slower than needed? I also thought I \
better make sure the persisting process completed even though it as taking ages or \
else there may have been only a partial translation. If I had not had the \
opensim\bin window open I would have thought the OpenSim.exe console was jammed and \
stopped wit with the X on the console window... I assume that would NOT have been \
good, so it could be a source fo problems if persisting objects takes so long. A \
better indication of progress might be to put a dot out every 50 or 100 objects \
persisted on the console to remind the user the region OpenSim.exe still need time to \
complete.<div class="HOEnZb"> <div class="h5"><br>
<br>
<br>
<br>
<br>
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</div></div></blockquote></div><br></div>
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