diff --git a/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotSettings.java b/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotSettings.java
index fb7cd07..0fb090e 100644
--- a/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotSettings.java
+++ b/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotSettings.java
@@ -12,6 +12,7 @@ public class GnuplotSettings {
 	public final static int GNUPLOT_TOP_MARGIN = 57; // The top margin configured for gnuplot
 	public final static int GNUPLOT_BOTTOM_MARGIN = 76; // The bottom margin configured for gnuplot
 	public final static int GNUPLOT_TOP_BOTTOM_MARGIN = GNUPLOT_TOP_MARGIN + GNUPLOT_BOTTOM_MARGIN;
+	public final static int GNUPLOT_LEFT_RIGHT_MARGIN = GNUPLOT_LEFT_MARGIN+GNUPLOT_RIGHT_MARGIN;
 
 	private String terminal = "png";
 	private int height = 1200;
diff --git a/pdb-plotting/src/main/java/org/lucares/recommind/logs/LambdaFriendlyWriter.java b/pdb-plotting/src/main/java/org/lucares/recommind/logs/LambdaFriendlyWriter.java
new file mode 100644
index 0000000..0ef0e9b
--- /dev/null
+++ b/pdb-plotting/src/main/java/org/lucares/recommind/logs/LambdaFriendlyWriter.java
@@ -0,0 +1,79 @@
+package org.lucares.recommind.logs;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import org.lucares.pdb.api.RuntimeIOException;
+
+public class LambdaFriendlyWriter extends Writer{
+
+	private final Writer writer;
+	
+	public LambdaFriendlyWriter(Writer writer) {
+		this.writer = writer;
+	}
+
+	@Override
+	public void write(char[] cbuf, int off, int len)   {
+		try {
+			writer.write(cbuf, off, len);
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+	
+	@Override
+	public void write(int c)  {
+		try {
+			writer.write(c);
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+	
+	@Override
+	public void write(String str)  {
+		try {
+			writer.write(str);
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+	
+	@Override
+	public Writer append(CharSequence csq)   {
+		try {
+			return writer.append(csq);
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+	
+	@Override
+	public Writer append(char c)   {
+		try {
+			return writer.append(c);
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+
+	@Override
+	public void flush()   {
+		try {
+			writer.flush();
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+
+	@Override
+	public void close()   {
+		try {
+			writer.close();
+		} catch (IOException e) {
+			throw new RuntimeIOException(e);
+		}
+	}
+
+}
diff --git a/pdb-plotting/src/main/java/org/lucares/recommind/logs/ScatterPlot.java b/pdb-plotting/src/main/java/org/lucares/recommind/logs/ScatterPlot.java
index 7a677d8..a59b371 100644
--- a/pdb-plotting/src/main/java/org/lucares/recommind/logs/ScatterPlot.java
+++ b/pdb-plotting/src/main/java/org/lucares/recommind/logs/ScatterPlot.java
@@ -23,12 +23,15 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Stream;
 
+import org.apache.commons.lang3.math.NumberUtils;
 import org.lucares.collections.LongList;
+import org.lucares.collections.Sparse2DLongArray;
 import org.lucares.pdb.api.DateTimeRange;
 import org.lucares.pdb.api.GroupResult;
 import org.lucares.pdb.api.Query;
 import org.lucares.pdb.api.Result;
 import org.lucares.pdb.api.Tags;
+import org.lucares.pdb.plot.api.AxisScale;
 import org.lucares.pdb.plot.api.CustomAggregator;
 import org.lucares.pdb.plot.api.Limit;
 import org.lucares.pdb.plot.api.PlotSettings;
@@ -90,7 +93,9 @@ public class ScatterPlot {
 			final AtomicInteger idCounter = new AtomicInteger(0);
 			result.getGroups().stream().parallel().forEach(groupResult -> {
 				try {
-					final CsvSummary csvSummary = toCsv(groupResult, tmpDir, dateFrom, dateTo, plotSettings);
+					final CsvSummary csvSummary = true 
+							? toCsvDeduplicated(groupResult, tmpDir, dateFrom, dateTo, plotSettings)
+							:toCsv(groupResult, tmpDir, dateFrom, dateTo, plotSettings);
 
 					final int id = idCounter.incrementAndGet();
 					final String title = title(groupResult.getGroupedBy(), csvSummary);
@@ -286,6 +291,112 @@ public class ScatterPlot {
 				aggregator.getAggregatedData());
 
 	}
+	
+	private static CsvSummary toCsvDeduplicated(final GroupResult groupResult, final Path tmpDir, final OffsetDateTime dateFrom,
+			final OffsetDateTime dateTo, final PlotSettings plotSettings) throws IOException {
+
+		final File dataFile = File.createTempFile("data", ".dat", tmpDir.toFile());
+		final long start = System.nanoTime();
+		final Stream<LongList> timeValueStream = groupResult.asStream();
+		final long fromEpochMilli = dateFrom.toInstant().toEpochMilli();
+		final long toEpochMilli = dateTo.toInstant().toEpochMilli();
+		final boolean useMillis = (toEpochMilli - fromEpochMilli) < TimeUnit.MINUTES.toMillis(5);
+		final long plotAreaWidthInPx = plotSettings.getWidth() - GnuplotSettings.GNUPLOT_LEFT_RIGHT_MARGIN;
+		final long plotAreaHeightInPx = plotSettings.getHeight() - GnuplotSettings.GNUPLOT_TOP_BOTTOM_MARGIN;
+		final long epochMillisPerPixel = Math.max(1, (toEpochMilli - fromEpochMilli) / plotAreaWidthInPx);
+
+		final long minValue = plotSettings.getYRangeUnit() == TimeRangeUnitInternal.AUTOMATIC ? 0
+				: plotSettings.getYRangeUnit().toMilliSeconds(plotSettings.getYRangeMin());
+		final long maxValue = plotSettings.getYRangeUnit() == TimeRangeUnitInternal.AUTOMATIC ? Long.MAX_VALUE
+				: plotSettings.getYRangeUnit().toMilliSeconds(plotSettings.getYRangeMax());
+		final long durationMillisPerPixel = plotSettings.getYAxisScale() == AxisScale.LINEAR 
+				? Math.max(1, (maxValue -minValue) / plotAreaHeightInPx)
+				: 1;
+
+		final CustomAggregator aggregator = plotSettings.getAggregate().createCustomAggregator(tmpDir, fromEpochMilli,
+				toEpochMilli);
+
+		final Sparse2DLongArray matrix2d = new Sparse2DLongArray();
+		int count = 0; // number of values in the x-axis range (used to compute stats)
+		int plottedValues = 0;
+		long statsMaxValue = 0;
+		double statsCurrentAverage = 0.0;
+		long ignoredValues = 0;
+		final int separator = ',';
+		final int newline = '\n';
+		
+		final Iterator<LongList> it = timeValueStream.iterator();
+		while (it.hasNext()) {
+			final LongList entry = it.next();
+
+			for (int i = 0; i < entry.size(); i += 2) {
+
+				final long epochMilli = entry.get(i);
+				if (fromEpochMilli > epochMilli || epochMilli > toEpochMilli) {
+					ignoredValues++;
+					continue;
+				}
+
+				final long value = entry.get(i + 1);
+
+				aggregator.addValue(epochMilli, value);
+
+				// compute stats
+				count++;
+				statsMaxValue = Math.max(statsMaxValue, value);
+
+				// compute average (important to do this after 'count' has been incremented)
+				statsCurrentAverage = statsCurrentAverage + (value - statsCurrentAverage) / count;
+
+				// check if value is in the selected y-range
+				if (value < minValue || value > maxValue) {
+					ignoredValues++;
+					continue;
+				}
+
+				final long roundedEpochMilli = epochMilli - epochMilli % epochMillisPerPixel;
+				final long roundedValue = value - value % durationMillisPerPixel;
+				matrix2d.put(roundedEpochMilli, roundedValue, 1);
+
+				plottedValues++;
+			}
+		}
+		
+		
+		long[] actualValuesWritten = new long[1];
+		final StringBuilder formattedDateBuilder = new StringBuilder();
+		try (final LambdaFriendlyWriter output = new LambdaFriendlyWriter(new BufferedWriter(
+				new OutputStreamWriter(new FileOutputStream(dataFile), StandardCharsets.ISO_8859_1)));
+				final Formatter formatter = new Formatter(formattedDateBuilder);) {
+
+			matrix2d.forEach((epochMilli, value, __)-> {
+				
+				final String stringValue = LongUtils.longToString(value);
+				final String formattedDate;
+				
+				if (useMillis) {
+					formattedDateBuilder.delete(0, formattedDateBuilder.length());
+					formatter.format("%.3f", epochMilli / 1000.0);
+					formattedDate = formattedDateBuilder.toString();
+				} else {
+					formattedDate = String.valueOf(epochMilli / 1000);
+				}
+				
+				output.write(formattedDate);
+				output.write(separator);
+				output.write(stringValue);
+				output.write(newline);
+				actualValuesWritten[0]++;
+			});
+		}
+
+		METRICS_LOGGER.debug("wrote {} (actual: {} factor: {}%) values to csv in: {}ms (ignored {} values) use millis: {}, grouping={}, file={}",
+				 actualValuesWritten[0], count, (double)count/(actualValuesWritten[0]), (System.nanoTime() - start) / 1_000_000.0, ignoredValues, Boolean.toString(useMillis),
+				groupResult.getGroupedBy().asString(), dataFile);
+		return new CsvSummary(dataFile, count, plottedValues, statsMaxValue, statsCurrentAverage,
+				aggregator.getAggregatedData());
+
+	}
 
 	static String uniqueDirectoryName() {
 		return OffsetDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd_HH_mm_ss")) + "_"