[OSM-dev] Further Database optimisation and data size
steve at asklater.com
Thu Apr 20 20:54:19 BST 2006
* @ 20/04/06 07:50:35 PM nick at nickhill.co.uk wrote:
> From these tests, using integers is much faster for database retrieval
> on key columns.
> Storing the data completely in memory can be helpful, but is not
> necessarily overriding. Previous tests have shown that tripling the
> available memory from 340Mb to 980Mb for 100million points as doubles
> makes around 10% difference. That is on a 1.7Gb data set.
> The ease by which the queries can be performed in terms of processing
> power is perhaps of greatest importance. In addition, I plan to run an
> optimisation which will put most groups of tiles within 4 hard drive
> seeks of data retrieval for any table, without changing any SQL logic.
> (I have not yet finished tests on this).
I can't read perl well, does the test include converting the returned
data set rows back to lat/lon?
SteveC steve at asklater.com http://www.asklater.com/steve/
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