andi/perfdb
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cache location of root node

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The location of the root node is not cached in the nodeCache. So it had
to be read for every read or write access. We are still using a lock
when accessing the map. That makes it easy to cache the location.
This commit is contained in:
Andreas Huber
2020-10-04 16:42:25 +02:00
parent 598ee31c1d
commit d4d3d01405
1 changed files with 9 additions and 4 deletions
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13
block-storage/src/main/java/org/lucares/pdb/map/PersistentMap.java
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@@ -153,7 +153,10 @@ public class PersistentMap<K, V> implements AutoCloseable {
private final LRUCache<Long, PersistentMapDiskNode> nodeCache = new LRUCache<>(10_000); private final LRUCache<Long, PersistentMapDiskNode> nodeCache = new LRUCache<>(10_000);
private final LRUCache<K, V> valueCache = new LRUCache<>(1_000); private final LRUCache<K, V> valueCache = new LRUCache<>(10_000);
// guarded by: this
private volatile long nodeOffsetOfRootNode = -1;
public PersistentMap(final Path path, final Path storageBasePath, final EncoderDecoder<K> keyEncoder, public PersistentMap(final Path path, final Path storageBasePath, final EncoderDecoder<K> keyEncoder,
final EncoderDecoder<V> valueEncoder) { final EncoderDecoder<V> valueEncoder) {
@@ -161,6 +164,9 @@ public class PersistentMap<K, V> implements AutoCloseable {
this.keyEncoder = keyEncoder; this.keyEncoder = keyEncoder;
this.valueEncoder = valueEncoder; this.valueEncoder = valueEncoder;
initIfNew(); initIfNew();
final DiskBlock diskBlock = diskStore.getDiskBlock(NODE_OFFSET_TO_ROOT_NODE, diskStore.minAllocationSize());
nodeOffsetOfRootNode = diskBlock.getByteBuffer().getLong(0);
} }
@Override @Override
@@ -478,15 +484,14 @@ public class PersistentMap<K, V> implements AutoCloseable {
} }
private long readNodeOffsetOfRootNode() { private long readNodeOffsetOfRootNode() {
final DiskBlock diskBlock = diskStore.getDiskBlock(NODE_OFFSET_TO_ROOT_NODE, diskStore.minAllocationSize()); return nodeOffsetOfRootNode;
return diskBlock.getByteBuffer().getLong(0);
} }
private void writeNodeOffsetOfRootNode(final long newNodeOffsetToRootNode) { private void writeNodeOffsetOfRootNode(final long newNodeOffsetToRootNode) {
final DiskBlock diskBlock = diskStore.getDiskBlock(NODE_OFFSET_TO_ROOT_NODE, diskStore.minAllocationSize()); final DiskBlock diskBlock = diskStore.getDiskBlock(NODE_OFFSET_TO_ROOT_NODE, diskStore.minAllocationSize());
diskBlock.getByteBuffer().putLong(0, newNodeOffsetToRootNode); diskBlock.getByteBuffer().putLong(0, newNodeOffsetToRootNode);
diskBlock.force(); diskBlock.force();
nodeOffsetOfRootNode = newNodeOffsetToRootNode;
} }
} }