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https://issues.apache.org/jira/browse/FLINK-10082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16586105#comment-16586105
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ASF GitHub Bot commented on FLINK-10082:
----------------------------------------
zentol closed pull request #6580: [FLINK-10082][metrics][slf4j] Provide initial
size to StringBuilder
URL: https://github.com/apache/flink/pull/6580
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git
a/flink-metrics/flink-metrics-slf4j/src/main/java/org/apache/flink/metrics/slf4j/Slf4jReporter.java
b/flink-metrics/flink-metrics-slf4j/src/main/java/org/apache/flink/metrics/slf4j/Slf4jReporter.java
index 5efac30637f..124efe227a3 100644
---
a/flink-metrics/flink-metrics-slf4j/src/main/java/org/apache/flink/metrics/slf4j/Slf4jReporter.java
+++
b/flink-metrics/flink-metrics-slf4j/src/main/java/org/apache/flink/metrics/slf4j/Slf4jReporter.java
@@ -42,6 +42,9 @@
private static final Logger LOG =
LoggerFactory.getLogger(Slf4jReporter.class);
private static final String lineSeparator = System.lineSeparator();
+ // the initial size roughly fits ~150 metrics with default scope
settings
+ private int previousSize = 16384;
+
@VisibleForTesting
Map<Gauge<?>, String> getGauges() {
return gauges;
@@ -72,7 +75,10 @@ public void close() {
@Override
public void report() {
- StringBuilder builder = new StringBuilder();
+ // initialize with previous size to avoid repeated resizing of
backing array
+ // pad the size to allow deviations in the final string, for
example due to different double value representations
+ StringBuilder builder = new StringBuilder((int) (previousSize *
1.1));
+
builder
.append(lineSeparator)
.append("=========================== Starting metrics
report ===========================")
@@ -134,6 +140,8 @@ public void report() {
.append("=========================== Finished metrics
report ===========================")
.append(lineSeparator);
LOG.info(builder.toString());
+
+ previousSize = builder.length();
}
@Override
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> Initialize StringBuilder in Slf4jReporter with estimated size
> -------------------------------------------------------------
>
> Key: FLINK-10082
> URL: https://issues.apache.org/jira/browse/FLINK-10082
> Project: Flink
> Issue Type: Improvement
> Components: Metrics
> Affects Versions: 1.5.2, 1.6.0
> Reporter: Chesnay Schepler
> Assignee: Chesnay Schepler
> Priority: Major
> Labels: pull-request-available
>
> The {{Slf4jReporter}} uses a StringBuilder to generate the report that is
> later logged. Currently we don't pass the initial size, which for large
> deployments can result in frequent resizing of the backing array.
> We could either estimate the expected size based on the # of metrics, or
> store the size of the last report (given that the total metrics space is
> fairly constant).
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