108 lines
3.3 KiB
Java
108 lines
3.3 KiB
Java
package org.warp.cowdb.database;
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import it.unimi.dsi.fastutil.longs.*;
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import it.unimi.dsi.fastutil.objects.ObjectIterator;
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import java.io.IOException;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.Future;
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import static org.warp.cowdb.IBlocksMetadata.ERROR_BLOCK_ID;
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public class DatabaseReferencesMetadataCache {
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private static final int GOOD_CACHE_SIZE = 70000;
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private static final int MAX_CACHE_SIZE = 100000;
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private final Long2LongMap references2Blocks = new Long2LongLinkedOpenHashMap(MAX_CACHE_SIZE);
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private final Object readAccessLock = new Object();
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private final Object writeAccessLock = new Object();
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private final DatabaseReferencesMetadataCacheFlusher flusher;
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private volatile boolean closed;
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public DatabaseReferencesMetadataCache(DatabaseReferencesMetadataCacheFlusher flusher) {
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this.flusher = flusher;
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}
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public long get(long reference) throws IOException {
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if (closed) throw new IOException("Cache already closed!");
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synchronized (readAccessLock) {
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return references2Blocks.getOrDefault(reference, ERROR_BLOCK_ID);
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}
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}
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public void put(long reference, long value) throws IOException {
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if (closed) return;
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synchronized (readAccessLock) {
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synchronized (writeAccessLock) {
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references2Blocks.put(reference, value);
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}
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}
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this.flush();
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}
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public void remove(long reference) {
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if (closed) return;
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synchronized (readAccessLock) {
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synchronized (writeAccessLock) {
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references2Blocks.remove(reference);
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}
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}
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}
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private void flush() throws IOException {
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if (closed) return;
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int references2BlocksSize = references2Blocks.size();
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if (references2BlocksSize > MAX_CACHE_SIZE) {
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synchronized (writeAccessLock) {
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ObjectIterator<Long2LongMap.Entry> entriesIterator = references2Blocks.long2LongEntrySet().iterator();
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List<Future<?>> entriesToFlush = new LinkedList<>();
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while (references2BlocksSize > GOOD_CACHE_SIZE) {
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Long2LongMap.Entry entry = entriesIterator.next();
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entriesToFlush.add(flusher.flush(entry.getLongKey(), entry.getLongValue()));
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entriesIterator.remove();
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references2BlocksSize--;
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}
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try {
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for (Future<?> entryToFlush : entriesToFlush) {
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entryToFlush.get();
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}
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} catch (InterruptedException e) {
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throw new IOException(e);
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} catch (ExecutionException e) {
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throw new IOException(e.getCause());
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}
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}
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}
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}
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public void close() throws IOException {
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synchronized (readAccessLock) {
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synchronized (writeAccessLock) {
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if (!closed) {
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closed = true;
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int references2BlocksSize = references2Blocks.size();
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ObjectIterator<Long2LongMap.Entry> entriesIterator = references2Blocks.long2LongEntrySet().iterator();
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List<Future<?>> entriesToFlush = new LinkedList<>();
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while (references2BlocksSize > 0) {
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Long2LongMap.Entry entry = entriesIterator.next();
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entriesToFlush.add(flusher.flush(entry.getLongKey(), entry.getLongValue()));
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references2BlocksSize--;
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}
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try {
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for (Future<?> entryToFlush : entriesToFlush) {
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entryToFlush.get();
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}
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} catch (InterruptedException e) {
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throw new IOException(e);
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} catch (ExecutionException e) {
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throw new IOException(e.getCause());
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}
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}
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}
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}
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}
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}
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