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New SQL reference page for the SUBSAMPLE clause covering LTTB, M4, and MinMax downsampling algorithms with SVG diagrams, runnable examples on fx_trades, gap-preserving LTTB, and configuration reference.
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🚀 Build success! Latest successful preview: https://preview-424--questdb-documentation.netlify.app/docs/ Commit SHA: 50db1af
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Avoid stretching all doc images by targeting only img[src*="/subsample/"] instead of article img.
Split gap SVG into three separate charts with individual legends. Add small gap to dataset to illustrate threshold behavior. Use QuestDB color palette (pink lines, cyan titles, gray dots). Match inline SQL examples to chart storytelling (24 hourly bars). Add boundary markers distinguishing gaps from bucket boundaries.
Tweak dataset so M4 visibly outperforms MinMax (late spike with pullback). Explain envelope, triangle method, and first/last advantage for users unfamiliar with downsampling.
Move gap-preserving LTTB right after LTTB. Add uniform (evenly spaced rows) and cadence (every Nth row with optional random offset) sections. Update syntax block and comparison table.
Add uniform (evenly spaced) and cadence (every Nth row) sections with SVG diagrams. Move gap-preserving LTTB under LTTB heading. Reorder MinMax before M4. Add relative cost row to comparison table.
Add uniform, cadence, and gap-preserving LTTB to the chart-ready examples section. Make DECLARE example demoable. Replace Grafana reference with generic programmatic integration.
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Summary
SUBSAMPLEclause - time-series downsampling that selects real rows (no interpolation)fx_tradesdemo datasetcairo.sql.subsample.max.rowsto configuration referenceSUBSAMPLEto sidebar under SELECT, after SAMPLE BYscripts/gen_subsample_svgs.pyfor rebuilding diagramsDependencies