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List:       postgis-devel
Subject:    Re: [postgis-devel] about serialized form
From:       Paul Ramsey <pramsey () opengeo ! org>
Date:       2009-02-26 15:37:16
Message-ID: 30fe546d0902260737g7a841461l4a01def0253ef413 () mail ! gmail ! com
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Current form is good for size, but any read of coordinates requires
memcpy'ing the information into an aligned space. And profiling
PostGIS, one now finds that much of our CPU time is spent in memcpy.
Reading directly from the unaligned serialized form is not possible on
architectures like Sparc, though it does work on x86. So for
performance reasons, having an aligned structure would be nice.

On Thu, Feb 26, 2009 at 5:38 AM, xie_jiong <xie_jiong@163.com> wrote:
> I've read the postgis-svn\doc\rfc\postgis_rfc_02 and
> WKTRaster\doc\RFC1-SerializedFormat, and
> puzzled about why should make serialized form aligned? For example, the
> current version of serialized
> LW-geometry doesn't get aligned,right? They are written to and read from
> disk by byte stream, and
> the size is compact, are there any problem?
>
> Thanks!
>
> Jiong
> _______________________________________________
> postgis-devel mailing list
> postgis-devel@postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-devel
>
>
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