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HDFS-11383. Intern strings in BlockLocation and ExtendedBlock. Contributed by Misha Dmitriev.

This commit is contained in:
Andrew Wang 2017-06-01 15:20:18 -07:00
parent 219f4c199e
commit 7101477e47
3 changed files with 40 additions and 34 deletions
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21
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/BlockLocation.java
View File

@ -22,6 +22,7 @@ import java.io.Serializable;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.util.StringInterner;
/**
* Represents the network location of a block, information about the hosts
@ -114,27 +115,27 @@ public class BlockLocation implements Serializable {
if (names == null) {
this.names = EMPTY_STR_ARRAY;
} else {
this.names = names;
this.names = StringInterner.internStringsInArray(names);
}
if (hosts == null) {
this.hosts = EMPTY_STR_ARRAY;
} else {
this.hosts = hosts;
this.hosts = StringInterner.internStringsInArray(hosts);
}
if (cachedHosts == null) {
this.cachedHosts = EMPTY_STR_ARRAY;
} else {
this.cachedHosts = cachedHosts;
this.cachedHosts = StringInterner.internStringsInArray(cachedHosts);
}
if (topologyPaths == null) {
this.topologyPaths = EMPTY_STR_ARRAY;
} else {
this.topologyPaths = topologyPaths;
this.topologyPaths = StringInterner.internStringsInArray(topologyPaths);
}
if (storageIds == null) {
this.storageIds = EMPTY_STR_ARRAY;
} else {
this.storageIds = storageIds;
this.storageIds = StringInterner.internStringsInArray(storageIds);
}
if (storageTypes == null) {
this.storageTypes = EMPTY_STORAGE_TYPE_ARRAY;
@ -238,7 +239,7 @@ public class BlockLocation implements Serializable {
if (hosts == null) {
this.hosts = EMPTY_STR_ARRAY;
} else {
this.hosts = hosts;
this.hosts = StringInterner.internStringsInArray(hosts);
}
}
@ -249,7 +250,7 @@ public class BlockLocation implements Serializable {
if (cachedHosts == null) {
this.cachedHosts = EMPTY_STR_ARRAY;
} else {
this.cachedHosts = cachedHosts;
this.cachedHosts = StringInterner.internStringsInArray(cachedHosts);
}
}
@ -260,7 +261,7 @@ public class BlockLocation implements Serializable {
if (names == null) {
this.names = EMPTY_STR_ARRAY;
} else {
this.names = names;
this.names = StringInterner.internStringsInArray(names);
}
}
@ -271,7 +272,7 @@ public class BlockLocation implements Serializable {
if (topologyPaths == null) {
this.topologyPaths = EMPTY_STR_ARRAY;
} else {
this.topologyPaths = topologyPaths;
this.topologyPaths = StringInterner.internStringsInArray(topologyPaths);
}
}
@ -279,7 +280,7 @@ public class BlockLocation implements Serializable {
if (storageIds == null) {
this.storageIds = EMPTY_STR_ARRAY;
} else {
this.storageIds = storageIds;
this.storageIds = StringInterner.internStringsInArray(storageIds);
}
}

37
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringInterner.java
View File

@ -25,8 +25,9 @@ import com.google.common.collect.Interner;
import com.google.common.collect.Interners;
/**
* Provides equivalent behavior to String.intern() to optimize performance,
* whereby does not consume memory in the permanent generation.
* Provides string interning utility methods. For weak interning,
* we use the standard String.intern() call, that performs very well
* (no problems with PermGen overflowing, etc.) starting from JDK 7.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
@ -35,20 +36,9 @@ public class StringInterner {
/**
* Retains a strong reference to each string instance it has interned.
*/
private final static Interner<String> strongInterner;
/**
* Retains a weak reference to each string instance it has interned.
*/
private final static Interner<String> weakInterner;
static {
strongInterner = Interners.newStrongInterner();
weakInterner = Interners.newWeakInterner();
}
private final static Interner<String> STRONG_INTERNER =
Interners.newStrongInterner();
/**
* Interns and returns a reference to the representative instance
* for any of a collection of string instances that are equal to each other.
@ -62,7 +52,7 @@ public class StringInterner {
if (sample == null) {
return null;
}
return strongInterner.intern(sample);
return STRONG_INTERNER.intern(sample);
}
/**
@ -78,7 +68,18 @@ public class StringInterner {
if (sample == null) {
return null;
}
return weakInterner.intern(sample);
return sample.intern();
}
/**
* Interns all the strings in the given array in place,
* returning the same array.
*/
public static String[] internStringsInArray(String[] strings) {
for (int i = 0; i < strings.length; i++) {
strings[i] = weakIntern(strings[i]);
}
return strings;
}
}

16
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ExtendedBlock.java
View File

@ -17,6 +17,7 @@
*/
package org.apache.hadoop.hdfs.protocol;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
@ -42,13 +43,13 @@ public class ExtendedBlock {
}
public ExtendedBlock(String poolId, Block b) {
this.poolId = poolId;
this.poolId = poolId != null ? poolId.intern() : null;
this.block = b;
}
public ExtendedBlock(final String poolId, final long blkid, final long len,
final long genstamp) {
this.poolId = poolId;
this.poolId = poolId != null ? poolId.intern() : null;
block = new Block(blkid, len, genstamp);
}
@ -86,7 +87,7 @@ public class ExtendedBlock {
}
public void set(String poolId, Block blk) {
this.poolId = poolId;
this.poolId = poolId != null ? poolId.intern() : null;
this.block = blk;
}
@ -107,13 +108,16 @@ public class ExtendedBlock {
return false;
}
ExtendedBlock b = (ExtendedBlock)o;
return b.block.equals(block) && b.poolId.equals(poolId);
return b.block.equals(block) &&
(b.poolId != null ? b.poolId.equals(poolId) : poolId == null);
}
@Override // Object
public int hashCode() {
int result = 31 + poolId.hashCode();
return (31 * result + block.hashCode());
return new HashCodeBuilder(31, 17).
append(poolId).
append(block).
toHashCode();
}
@Override // Object