Expose max auto resizes metric
Currently, only the number of auto resizes is exposed as a metric.
When this value reaches 0 it is no longer possible to
expand the cache.
However, it is not possible to know the maximum number of auto-resizes
that the cache could go through.
Expose the maximum number of auto-resizes as a metric, so that can be
used together with the remaining auto-resizes to evaluate the overall
utilization of the cache.
Bug: Issue 15458
Change-Id: Ie81684950a28f3e2420bddfcaa10b7db218d00fb
diff --git a/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheImpl.java b/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheImpl.java
index 04ef4d7..76ae8a4 100644
--- a/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheImpl.java
+++ b/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheImpl.java
@@ -66,7 +66,7 @@
this.mem = memLoader.asInMemoryCacheBypass();
ChronicleMapStorageMetrics metrics = new ChronicleMapStorageMetrics(new DisabledMetricMaker());
- metrics.registerCallBackMetrics(def.name(), store, hotEntries);
+ metrics.registerCallBackMetrics(def.name(), this);
}
ChronicleMapCacheImpl(
@@ -87,7 +87,7 @@
this.store = store;
ChronicleMapStorageMetrics metrics = new ChronicleMapStorageMetrics(metricMaker);
- metrics.registerCallBackMetrics(def.name(), store, hotEntries);
+ metrics.registerCallBackMetrics(def.name(), this);
}
@SuppressWarnings({"unchecked", "cast", "rawtypes"})
@@ -153,13 +153,13 @@
this.metricMaker = metricMaker;
}
- <K, V> void registerCallBackMetrics(
- String name, ChronicleMap<KeyWrapper<K>, TimedValue<V>> store, InMemoryLRU<K> hotEntries) {
+ <K, V> void registerCallBackMetrics(String name, ChronicleMapCacheImpl<K, V> cache) {
String sanitizedName = metricMaker.sanitizeMetricName(name);
String PERCENTAGE_FREE_SPACE_METRIC =
"cache/chroniclemap/percentage_free_space_" + sanitizedName;
String REMAINING_AUTORESIZES_METRIC =
"cache/chroniclemap/remaining_autoresizes_" + sanitizedName;
+ String MAX_AUTORESIZES_METRIC = "cache/chroniclemap/max_autoresizes_" + sanitizedName;
String HOT_KEYS_CAPACITY_METRIC = "cache/chroniclemap/hot_keys_capacity_" + sanitizedName;
String HOT_KEYS_SIZE_METRIC = "cache/chroniclemap/hot_keys_size_" + sanitizedName;
@@ -168,7 +168,7 @@
Long.class,
new Description(
String.format("The amount of free space in the %s cache as a percentage", name)),
- () -> (long) store.percentageFreeSpace());
+ () -> (long) cache.store.percentageFreeSpace());
metricMaker.newCallbackMetric(
REMAINING_AUTORESIZES_METRIC,
@@ -176,11 +176,11 @@
new Description(
String.format(
"The number of times the %s cache can automatically expand its capacity", name)),
- store::remainingAutoResizes);
+ cache.store::remainingAutoResizes);
metricMaker.newConstantMetric(
HOT_KEYS_CAPACITY_METRIC,
- hotEntries.getCapacity(),
+ cache.hotEntries.getCapacity(),
new Description(
String.format(
"The number of hot cache keys for %s cache that can be kept in memory", name)));
@@ -191,7 +191,15 @@
new Description(
String.format(
"The number of hot cache keys for %s cache that are currently in memory", name)),
- hotEntries::size);
+ cache.hotEntries::size);
+
+ metricMaker.newConstantMetric(
+ MAX_AUTORESIZES_METRIC,
+ cache.maxAutoResizes(),
+ new Description(
+ String.format(
+ "The maximum number of times the %s cache can automatically expand its capacity",
+ name)));
}
}
@@ -415,9 +423,13 @@
* (`getExtraTiersInUse`) shows the overall percentage.
*/
VanillaChronicleMap vanillaStore = (VanillaChronicleMap) store;
- double maxResizes = config.getMaxBloatFactor() * vanillaStore.actualSegments;
long usedResizes = vanillaStore.globalMutableState().getExtraTiersInUse();
- return usedResizes * 100 / maxResizes;
+ return usedResizes * 100 / maxAutoResizes();
+ }
+
+ @SuppressWarnings("rawtypes")
+ public double maxAutoResizes() {
+ return config.getMaxBloatFactor() * ((VanillaChronicleMap) store).actualSegments;
}
public String name() {
diff --git a/src/main/resources/Documentation/metrics.md b/src/main/resources/Documentation/metrics.md
index 8e176ef..013a6c8 100644
--- a/src/main/resources/Documentation/metrics.md
+++ b/src/main/resources/Documentation/metrics.md
@@ -17,6 +17,9 @@
See the [official documentation](https://javadoc.io/static/net.openhft/chronicle-map/3.20.83/net/openhft/chronicle/map/ChronicleMap.html#remainingAutoResizes--)
for more information.
+* cache/chroniclemap/max_autoresizes_<cache-name>
+ : The maximum number of times the cache can automatically expand its capacity.
+
* cache/chroniclemap/hot_keys_capacity_<cache-name>
: Constant number of hot keys for the cache that can be kept in memory.
diff --git a/src/test/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheTest.java b/src/test/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheTest.java
index 91ddbe3..6cc4c05 100644
--- a/src/test/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheTest.java
+++ b/src/test/java/com/googlesource/gerrit/modules/cache/chroniclemap/ChronicleMapCacheTest.java
@@ -403,6 +403,21 @@
}
@Test
+ public void shouldTriggerMaxAutoResizeMetric() throws Exception {
+ String cachedValue = UUID.randomUUID().toString();
+ String maxAutoResizeMetricName = "cache/chroniclemap/max_autoresizes_" + testCacheName;
+ gerritConfig.setInt("cache", testCacheName, "maxEntries", 2);
+ gerritConfig.setInt("cache", testCacheName, "avgKeySize", cachedValue.getBytes().length);
+ gerritConfig.setInt("cache", testCacheName, "avgValueSize", valueSize(cachedValue));
+ gerritConfig.setInt("cache", testCacheName, "maxBloatFactor", 3);
+ gerritConfig.save();
+
+ newCacheWithMetrics(testCacheName, cachedValue);
+
+ assertThat(getMetric(maxAutoResizeMetricName).getValue()).isEqualTo(3);
+ }
+
+ @Test
public void shouldTriggerHotKeysCapacityCacheMetric() throws Exception {
String cachedValue = UUID.randomUUID().toString();
int percentageHotKeys = 60;
@@ -487,6 +502,7 @@
String hotKeySizeMetricName = "cache/chroniclemap/hot_keys_size_" + sanitized;
String percentageFreeMetricName = "cache/chroniclemap/percentage_free_space_" + sanitized;
String autoResizeMetricName = "cache/chroniclemap/remaining_autoresizes_" + sanitized;
+ String maxAutoResizeMetricName = "cache/chroniclemap/max_autoresizes_" + sanitized;
String hotKeyCapacityMetricName = "cache/chroniclemap/hot_keys_capacity_" + sanitized;
newCacheWithMetrics(cacheName, null);
@@ -494,6 +510,7 @@
getMetric(hotKeySizeMetricName);
getMetric(percentageFreeMetricName);
getMetric(autoResizeMetricName);
+ getMetric(maxAutoResizeMetricName);
getMetric(hotKeyCapacityMetricName);
}
