[OSM-dev] mmap()

Marcus Wolschon Marcus at wolschon.biz
Thu Dec 4 19:45:26 GMT 2008


2008/12/4 Stefan de Konink <stefan at konink.de>:
> Marcus Wolschon wrote:
>> 2008/12/4 Stefan de Konink <stefan at konink.de>:
>>> Marcus Wolschon wrote:
>>>> The structure is mutable, meaning you can add, modify and
>>>> remove nodes, ways and attributes at will.
>>> How did you solve fragmentation?
>>
>> Fragmentation occurs only in variable-length -records.
>> I chose a fixed-length-record to avoid this issue.
>> It allows for trivial reuse of empty spaces and speeds
>> up seeking in the file.
>
> So you do not maintain order, only use indices?

That is correct.
It would be too expensive to keep any kind of order
when modifying a file containing the world or the
size the world-file will have in..say..5 years.

Marcus




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