[OSM-talk] osmarender tile server broken?

[Frederik Ramm]

Hi,

> 1. it is not a "funky" C program. It would be as simple as you can get -
>    literally extract a series of bytes from a file.

Surely it will also require some sort of directory to know where the 
individual "series of bytes" start and where they end, as our PNG files 
tend to vary in size?

And surely you do not mean to call that simple C program as a CGI which 
would involve even more overhead than running a PHP script does? You 
will have to make an Apache module if you want to avoid re-introducing 
the performance problems we're hoping to shed.

This C program is either going to be slow and buggy, or it is going to 
be anything but simple. And it is also likely that nobody but the author 
will really understand what it does.

Plus, it will make it impossible to access tiles by any other means, 
e.g. by issuing a "find" command. In that, it would be even worse than 
the Mysql version was.

> an existing program such as ar or
> unzip should work just as well.

You do not want to have nine parallel "unzip" processes everytime 
someone views a tiny portion of the map!

> When I tried thousands of files in one directory on ext3 a couple of years ago,
> directory listing was slower than running your average MySQL query... ;-).

Ok, the "max. 1000 entries per directory" structure proposed in the wiki 
is fine too.

> We're talking about OSM here, and like many projects, the quickest way of
> getting something done is to do it yourself.

Yes but you have to be reasonable, and when you find that you can either 
produce a third-grade solution yourself with a lot of work *or* politely 
ask an over-worked admin to do the right thing, then it is reasonable to 
try and get the right thing done instead of just plodding along because 
anything you cannot do yourself means communication ;-)

 > tiles at home is desperately in need
> of something to make it faster, and changing stuff like filesystems needs others
> to plan and make it happen - Steve and Nick are busy people, like the rest of
> us. Even doing loopback filesystems needs an admin to mount it for you.

In that case, tiles at home would need more admins, not more hackish and 
resource-wasting solutions created because one didn't want to bother an 
admin!

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'