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29612Re: krpano and tiles in ZIP files

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  • Ingemar Bergmark
    Jun 2, 2009
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      --- In PanoToolsNG@yahoogroups.com, Roger Howard <rogerhoward@...>
      > wrote:
      >
      > I did something just like this for Zoomify some years ago... it
      > raised enough flags on their end that I switched hosts for that
      > project to one that didn't care about inode counts. It added a lot
      > of CPU load, IIRC, to an otherwise low-load viewer since you had to
      > get PHP involved with every tile operation... it also adds a lot of
      > additional i/o overhead since there's several extra reads (parsing
      > the ZIP header) per tile.
      > I played with other approaches - the most obvious is to pre-parse
      > each ZIP file and create an index in a database, which holds just
      > the file offsets of each tile within the ZIP. Assuming the zip is
      > saved without compression (since there's no real benefit) then you
      > can unpack files from it pretty quickly with a lot less load with
      > simple file reads by byterange than actually using the PHP zip
      > libraries for each tile read.
      > Depending on your host, you may also consider storing tiles in the
      > database - seems stupid, but in many cases there's a lot more
      > excess database capacity than storage/inodes and it'd be trivial to
      > store each tile in a blob and write a php shim for it.
      >

      Thanks for the extra info, we'll see what happens with my host.
      The pre-parsing approach is very interesting, I'm definately going to give that a try...

      / Ingemar
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