.nornir/assets/thund-write-mode.svg
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<text x="24" y="26" font-weight="700" font-size="16">Dataset.write_mode — overwrite vs append on a re-run</text>
<text x="24" y="46" fill="#555" font-size="12">A partitioned sink writes fresh part-files each run; the mode decides whether a re-run clears first or piles up.</text>
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<text x="99" y="180" text-anchor="middle" font-weight="600">Flow → sink</text>
<text x="99" y="202" text-anchor="middle" fill="#555" font-size="11">by_region</text>
<text x="99" y="220" text-anchor="middle" fill="#555" font-size="11">3 rows / run</text>
<!-- APPEND lane (green, accumulates) -->
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<text x="196" y="132" fill="#2f8f4e" font-size="11" font-weight="600">Append</text>
<text x="248" y="86" fill="#2f8f4e" font-size="12" font-weight="600">write_mode = Append (default) — accumulate</text>
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<text x="413" y="120" text-anchor="middle" font-weight="600">out/by_region/ (dir kept)</text>
<text x="413" y="140" text-anchor="middle" fill="#555" font-size="11">run 1: region=US/part-a region=EU/part-a</text>
<text x="413" y="156" text-anchor="middle" fill="#555" font-size="11">run 2: region=US/part-b region=EU/part-b (+added)</text>
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<text x="662" y="130" text-anchor="middle" font-weight="700" font-size="13">6 rows</text>
<text x="662" y="148" text-anchor="middle" fill="#7a3fb3" font-size="11">two generations</text>
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<!-- OVERWRITE lane (orange, clears first) -->
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<text x="188" y="258" fill="#c26a2b" font-size="11" font-weight="600">Overwrite</text>
<text x="248" y="214" fill="#c26a2b" font-size="12" font-weight="600">write_mode = Overwrite — clear, then write</text>
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<text x="413" y="248" text-anchor="middle" font-weight="600">clear_sink_target → remove_dir_all</text>
<text x="413" y="268" text-anchor="middle" fill="#555" font-size="11">run 2: dir wiped first, then region=US/ region=EU/</text>
<text x="413" y="284" text-anchor="middle" fill="#c26a2b" font-size="11" font-style="italic">fresh-dir semantics</text>
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<text x="662" y="258" text-anchor="middle" font-weight="700" font-size="13">3 rows</text>
<text x="662" y="276" text-anchor="middle" fill="#7a3fb3" font-size="11">one generation</text>
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<!-- additive note -->
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<text x="812" y="174" text-anchor="middle" font-weight="600" font-size="12">additive (L2)</text>
<text x="812" y="194" text-anchor="middle" fill="#555" font-size="11">default = Append</text>
<text x="812" y="210" text-anchor="middle" fill="#555" font-size="11">serde-skipped</text>
<text x="812" y="226" text-anchor="middle" fill="#555" font-size="11">native file sink</text>
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