This is interesting. Is the entire R tree loaded into memory at once, or
can it be partially loaded as needed?
I have seen some blog posts about using mysql spatial features, which found
that it loads the whole R tree into memory, and consequently has some very
poor performance features for large tables, or large numbers of tables.
UCSC has developed a different technique for genomic spatial queries, where
they calculate something like a fixed R tree bin ID (fixed meaning it's the
same bins for every dataset, it doesn't create bins based on the data) for
each feature, and store the bin ID in a B-tree indexed column. I believe
this doesn't require loading the whole index into memory at once, though it
does require some application code to compose the queries on the bin
column, because they are moderately complex, and can't be encapsulated
easily into a sql function or view.
On Friday, April 19, 2013 2:38:29 AM UTC-7, Nicolas Fortin (OrbisGIS) wrote:
>
> Ok, the patch is done for OSGi and it works well.
>
> I should write Unit test but I don't find *unit test* on OSGi activator.
> I'm using IntelliJ, how do you create a valid project with H2 source ?
>
> How it works :
>
> The H2 Bundle Activator register into org.h2.Util.Utils an object that
> handle a specific kind of binary class name. This specific binary class
> name follow this structure
>
> "BundleSymbolicName:BundleVersion:JavaBinaryName"
>
> I don't find a standard way to describe such kind of structure. I could
> use Bundle Id (int) but this identifier can change after framework restart,
> and it is too opaque.
>
> This extended name allow OSGi developers to still using the "CREATE ALIAS"
> Sql query without doing any Java operation, neither deal with h2 packages.
>
> I'm working now on H2 trunk, still trying to figure out what is the best
> strategy for h2 spatial.
>
> Thank for you support.
>
> -Nicolas
>
> Le jeudi 18 avril 2013 17:12:59 UTC+2, Nicolas Fortin (OrbisGIS) a écrit :
>>
>> Thank your for the answer. I will work on the patch, trying to not break
>> anything. And I will send another patch for maven local build that do not
>> read the good version of the library (got stuck on home made build system).
>>
>> I will release also H2 Spatial OSGi integration and unit testing projects
>> also.
>>
>> For license I will see with my boss Erwan. Spatial feature would require
>> at least one library dependency JTS topology suite, is this a problem for
>> trunk development ? May be an optional build to enable spatial feature ?
>>
>> Best regards,
>>
>> -Nicolas
>> Le jeudi 18 avril 2013 16:27:30 UTC+2, Noel Grandin a écrit :
>>>
>>>
>>>
>>> On Thursday, 18 April 2013, Nicolas Fortin (OrbisGIS) wrote:
>>>
>>>> We are using H2 in an OSGi environment.
>>>>
>>>> I search an alternative to CREATE ALIAS in order to provide to h2 the
>>>> java Class.
>>>>
>>>> Maybe by calling something like org.h2.util.Utils.addUserClass("Class
>>>> name",Class<?> userClass);
>>>
>>>
>>>
>>> Are yes, I see your problem. In an osgi context the db does not know
>>> which class loader to use when loading the alias.
>>>
>>> For now I suggest you patch such a method in yourself. If you can't go
>>> that, I will send you a patch next week. (I'm at a conference this week)
>>>
>>>
>>>
>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
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