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Am 09.09.2010 20:25, schrieb Andrea Conti: |
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> Note however (this is the "it depends" part :) that piping does not |
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> affect whatever the programs might allocate or save internally: in your |
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> second example (which does not involve any disk writing in either case) |
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> "sort" needs to see the complete input before producing any output, so |
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> it will allocate enough memory to store it whether it is invoked alone |
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> or as part of a pipeline (in which case it will also stall the |
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> downstream pipeline section until the upstream pipe is closed). |
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> |
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When you look closer at `sort`, it is actually a quite impressive tool. |
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It sorts in-memory for small amounts of data and switches to temporary |
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files for larger. It can even compress those files to save disk space. |
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And it is still faster than most "business-grade" software for importing |
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data into data warehouses. |
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Throw `cut`, `paste`, `join` and `grep` into the mix and you can build |
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your own relational database system based on shell scripts ;) |
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