strangedb/src/main/java/it/cavallium/strangedb/database/DatabaseReferencesMetadataC...

112 lines
3.5 KiB
Java

package it.cavallium.strangedb.database;
import it.unimi.dsi.fastutil.longs.*;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import static it.cavallium.strangedb.database.IBlocksMetadata.ERROR_BLOCK_ID;
public class DatabaseReferencesMetadataCache {
private static final int GOOD_CACHE_SIZE = 70000;
private static final int MAX_CACHE_SIZE = 100000;
private final Long2LongMap references2Blocks = new Long2LongLinkedOpenHashMap(MAX_CACHE_SIZE);
private final Object readAccessLock = new Object();
private final Object writeAccessLock = new Object();
private final DatabaseReferencesMetadataCacheFlusher flusher;
private volatile boolean closed;
public DatabaseReferencesMetadataCache(DatabaseReferencesMetadataCacheFlusher flusher) {
this.flusher = flusher;
}
public long get(long reference) throws IOException {
synchronized (readAccessLock) {
if (closed) throw new IOException("Cache already closed!");
return references2Blocks.getOrDefault(reference, ERROR_BLOCK_ID);
}
}
public void put(long reference, long blockId) throws IOException {
synchronized (readAccessLock) {
synchronized (writeAccessLock) {
if (closed) return;
references2Blocks.put(reference, blockId);
}
}
this.flush();
}
private void flush() throws IOException {
synchronized (readAccessLock) {
synchronized (writeAccessLock) {
if (closed) return;
int references2BlocksSize = references2Blocks.size();
if (references2BlocksSize > MAX_CACHE_SIZE) {
synchronized (writeAccessLock) {
ObjectIterator<Long2LongMap.Entry> entriesIterator = references2Blocks.long2LongEntrySet().iterator();
List<Future<?>> entriesToFlush = new LinkedList<>();
while (references2BlocksSize > GOOD_CACHE_SIZE) {
Long2LongMap.Entry entry = entriesIterator.next();
entriesToFlush.add(flusher.flush(entry.getLongKey(), entry.getLongValue()));
entriesIterator.remove();
if (entriesToFlush.size() >= 1000) {
executeAsyncFlush(entriesToFlush);
}
references2BlocksSize--;
}
executeAsyncFlush(entriesToFlush);
}
}
}
}
}
public void close() throws IOException {
synchronized (readAccessLock) {
synchronized (writeAccessLock) {
if (!closed) {
closed = true;
int references2BlocksSize = references2Blocks.size();
ObjectIterator<Long2LongMap.Entry> entriesIterator = references2Blocks.long2LongEntrySet().iterator();
List<Future<?>> entriesToFlush = new LinkedList<>();
while (references2BlocksSize > 0) {
Long2LongMap.Entry entry = entriesIterator.next();
entriesToFlush.add(flusher.flush(entry.getLongKey(), entry.getLongValue()));
entriesIterator.remove();
if (entriesToFlush.size() >= 1000) {
executeAsyncFlush(entriesToFlush);
}
references2BlocksSize--;
}
executeAsyncFlush(entriesToFlush);
}
}
}
}
private void executeAsyncFlush(List<Future<?>> entriesToFlush) throws IOException {
synchronized (readAccessLock) {
synchronized (writeAccessLock) {
try {
for (Future<?> entryToFlush : entriesToFlush) {
entryToFlush.get();
}
} catch (InterruptedException e) {
throw new IOException(e);
} catch (ExecutionException e) {
throw new IOException(e.getCause());
} finally {
entriesToFlush.clear();
}
}
}
}
}