From 37eb05aebff9df2d0bb47dad678545d70fb5567e Mon Sep 17 00:00:00 2001
From: Andreas Huber <bitbucket@lucares.de>
Date: Sun, 24 Sep 2017 09:38:08 +0200
Subject: [PATCH] use unix timestamps in the CSVs used by gnuplot

This is faster by factor 4, because we don't have to format the date.
---
 .../recommind/logs/GnuplotSettings.java       |  2 +-
 .../org/lucares/recommind/logs/Plotter.java   | 30 ++++++++++++++-----
 2 files changed, 23 insertions(+), 9 deletions(-)

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 7f8e0c5..5953d9c 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
@@ -9,7 +9,7 @@ public class GnuplotSettings {
 	private String terminal = "png";
 	private int height = 1200;
 	private int width = 1600;
-	private String timefmt = "%Y-%m-%dT%H:%M:%S";
+	private String timefmt = "%s"; //"%Y-%m-%dT%H:%M:%S"; // TODO @ahr timefmt
 
 	// set format for x-axis
 	private String formatX = "%Y-%m-%d %H:%M:%S";
diff --git a/pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java b/pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java
index 6bb7c43..f62d0eb 100644
--- a/pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java
+++ b/pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java
@@ -15,9 +15,11 @@ import java.time.format.DateTimeFormatter;
 import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.Comparator;
+import java.util.Formatter;
 import java.util.Iterator;
 import java.util.List;
 import java.util.UUID;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
 import org.lucares.pdb.api.Entry;
@@ -130,15 +132,15 @@ public class Plotter {
 		if (minDate.until(maxDate, ChronoUnit.WEEKS) > 1) {
 			formatX = "%Y-%m-%d";
 			rotateX = 0;
-		} else if (minDate.until(maxDate, ChronoUnit.SECONDS) > 10) {
+		} else if (minDate.until(maxDate, ChronoUnit.SECONDS) > 30) {
 			formatX = "%Y-%m-%d %H:%M:%S";
 			rotateX = gnuplotSettings.getRotateXAxisLabel();
 		} else {
 			formatX = "%Y-%m-%d %H:%M:%.3S";
 			rotateX = gnuplotSettings.getRotateXAxisLabel();
 		}
-		formattedMinDate = minDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss"));
-		formattedMaxDate = maxDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss"));
+		formattedMinDate = String.valueOf(minDate.toEpochSecond());
+		formattedMaxDate = String.valueOf(maxDate.toEpochSecond());
 
 		gnuplotSettings.setFormatX(formatX);
 		gnuplotSettings.setRotateXAxisLabel(rotateX);
@@ -216,21 +218,33 @@ public class Plotter {
 		int count = 0;
 		final long fromEpochMilli = dateFrom.toInstant().toEpochMilli();
 		final long toEpochMilli = dateTo.toInstant().toEpochMilli();
+		final boolean useMillis = (toEpochMilli - fromEpochMilli) < TimeUnit.MINUTES.toMillis(5);
+		
 		long maxValue = 0;
 		long ignoredValues = 0;
 		final int separator = ',';
 		final int newline = '\n';
-		final DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
-		try (final Writer output = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(dataFile), StandardCharsets.US_ASCII));) {
+		final StringBuilder formattedDateBuilder = new StringBuilder();
+		try (final Writer output = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(dataFile), StandardCharsets.US_ASCII));
+				final Formatter formatter = new Formatter(formattedDateBuilder);) {
 
 			final Iterator<Entry> it = entries.iterator();
 			while (it.hasNext()) {
 				final Entry entry = it.next();
 
 				if (fromEpochMilli <= entry.getEpochMilli() && entry.getEpochMilli() <= toEpochMilli) {
-					final OffsetDateTime date = entry.getDate();
+					
 					final String value = String.valueOf(entry.getValue());
-					final String formattedDate = date.format(formatter);
+					final String formattedDate;
+					
+					if (useMillis){
+						formattedDateBuilder.delete(0, formattedDateBuilder.length());
+						formatter.format("%.3f", entry.getEpochMilli() / 1000.0);
+						formattedDate = formattedDateBuilder.toString();
+					}else {
+						formattedDate = String.valueOf(entry.getEpochMilli() / 1000);
+					}
+					
 					output.write(formattedDate);
 					output.write(separator);
 					output.write(value);
@@ -244,7 +258,7 @@ public class Plotter {
 			}
 		}
 
-		METRICS_LOGGER.debug("wrote {} values to csv in: {}ms (ignored {} values)", count, (System.nanoTime() - start) / 1_000_000.0, ignoredValues);
+		METRICS_LOGGER.debug("wrote {} values to csv in: {}ms (ignored {} values) use millis: {}", count, (System.nanoTime() - start) / 1_000_000.0, ignoredValues, Boolean.toString(useMillis));
 		return new CsvSummary(count,  maxValue);
 	}
 }