HDFS-16882. RBF: Add cache hit rate metric in MountTableResolver#getDestinationForPath (#5276)

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
Signed-off-by: Tao Li <tomscut@apache.org>
This commit is contained in:
hfutatzhanghb 2023-02-11 08:00:43 +08:00 committed by GitHub
parent 26fba8701c
commit f3c4277576
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4 changed files with 73 additions and 4 deletions

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@ -30,6 +30,7 @@
import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
import org.apache.hadoop.metrics2.lib.MetricsRegistry;
import org.apache.hadoop.metrics2.lib.MutableGaugeInt;
import org.apache.hadoop.metrics2.lib.MutableGaugeLong;
import org.apache.hadoop.metrics2.lib.MutableRate;
import org.apache.hadoop.classification.VisibleForTesting;
@ -136,6 +137,19 @@ public void setCacheSize(String name, int size) {
counter.set(size);
}
/**
* set the count of the location cache access information.
* @param name Name of the record.
* @param count count of the record.
*/
public void setLocationCache(String name, long count) {
MutableGaugeLong counter = (MutableGaugeLong) registry.get(name);
if (counter == null) {
counter = registry.newGauge(name, name, count);
}
counter.set(count);
}
@VisibleForTesting
public void reset() {
reads.resetMinMax();

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@ -42,6 +42,7 @@
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.LongAdder;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
@ -51,6 +52,7 @@
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hdfs.server.federation.metrics.StateStoreMetrics;
import org.apache.hadoop.hdfs.server.federation.resolver.order.DestinationOrder;
import org.apache.hadoop.hdfs.server.federation.router.Router;
import org.apache.hadoop.hdfs.server.federation.router.RouterRpcServer;
@ -97,6 +99,8 @@ public class MountTableResolver
private final TreeMap<String, MountTable> tree = new TreeMap<>();
/** Path -> Remote location. */
private final Cache<String, PathLocation> locationCache;
private final LongAdder locCacheMiss = new LongAdder();
private final LongAdder locCacheAccess = new LongAdder();
/** Default nameservice when no mount matches the math. */
private String defaultNameService = "";
@ -408,6 +412,9 @@ public boolean loadCache(boolean force) {
mountTable.getMountTableEntries(request);
List<MountTable> records = response.getEntries();
refreshEntries(records);
StateStoreMetrics metrics = this.getMountTableStore().getDriver().getMetrics();
metrics.setLocationCache("locationCacheMissed", this.getLocCacheMiss().sum());
metrics.setLocationCache("locationCacheAccessed", this.getLocCacheAccess().sum());
} catch (IOException e) {
LOG.error("Cannot fetch mount table entries from State Store", e);
return false;
@ -441,9 +448,12 @@ public PathLocation getDestinationForPath(final String path)
if (this.locationCache == null) {
res = lookupLocation(processTrashPath(path));
} else {
Callable<? extends PathLocation> meh = (Callable<PathLocation>) () ->
lookupLocation(processTrashPath(path));
Callable<? extends PathLocation> meh = (Callable<PathLocation>) () -> {
this.getLocCacheMiss().increment();
return lookupLocation(processTrashPath(path));
};
res = this.locationCache.get(processTrashPath(path), meh);
this.getLocCacheAccess().increment();
}
if (isTrashPath(path)) {
List<RemoteLocation> remoteLocations = new ArrayList<>();
@ -699,4 +709,12 @@ public void setDefaultNSEnable(boolean defaultNSRWEnable) {
public void setDisabled(boolean disable) {
this.disabled = disable;
}
public LongAdder getLocCacheMiss() {
return locCacheMiss;
}
public LongAdder getLocCacheAccess() {
return locCacheAccess;
}
}

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@ -73,7 +73,7 @@ public Class<R> getRecordClass() {
*
* @return State Store driver.
*/
protected StateStoreDriver getDriver() {
public StateStoreDriver getDriver() {
return this.driver;
}

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@ -729,4 +729,41 @@ public void testInvalidateCache() throws Exception {
assertEquals("2->/testInvalidateCache/foo", mountTable
.getDestinationForPath("/testInvalidateCache/foo").toString());
}
/**
* Test location cache hit when get destination for path.
*/
@Test
public void testLocationCacheHitrate() throws Exception {
List<MountTable> entries = new ArrayList<>();
// Add entry and test location cache
Map<String, String> map1 = getMountTableEntry("1", "/testlocationcache");
MountTable entry1 = MountTable.newInstance("/testlocationcache", map1);
entries.add(entry1);
Map<String, String> map2 = getMountTableEntry("2",
"/anothertestlocationcache");
MountTable entry2 = MountTable.newInstance("/anothertestlocationcache",
map2);
entries.add(entry2);
mountTable.refreshEntries(entries);
mountTable.getLocCacheAccess().reset();
mountTable.getLocCacheMiss().reset();
assertEquals("1->/testlocationcache",
mountTable.getDestinationForPath("/testlocationcache").toString());
assertEquals("2->/anothertestlocationcache",
mountTable.getDestinationForPath("/anothertestlocationcache")
.toString());
assertEquals(2, mountTable.getLocCacheMiss().intValue());
assertEquals("1->/testlocationcache",
mountTable.getDestinationForPath("/testlocationcache").toString());
assertEquals(3, mountTable.getLocCacheAccess().intValue());
// Cleanup before exit
mountTable.removeEntry("/testlocationcache");
mountTable.removeEntry("/anothertestlocationcache");
}
}