LeiRui commented on a change in pull request #262: [IOTDB-144]meta data cache
for query
URL: https://github.com/apache/incubator-iotdb/pull/262#discussion_r306152636
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File path:
iotdb/src/main/java/org/apache/iotdb/db/engine/cache/DeviceMetaDataCache.java
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@@ -19,77 +19,144 @@
package org.apache.iotdb.db.engine.cache;
import java.io.IOException;
-import java.util.LinkedHashMap;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
import java.util.Map;
-import java.util.Objects;
+import java.util.Set;
import java.util.concurrent.atomic.AtomicLong;
+import org.apache.iotdb.db.conf.IoTDBConfig;
+import org.apache.iotdb.db.conf.IoTDBDescriptor;
+import org.apache.iotdb.db.engine.StorageEngine;
+import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
import org.apache.iotdb.tsfile.file.metadata.TsDeviceMetadata;
import org.apache.iotdb.tsfile.file.metadata.TsFileMetaData;
+import org.apache.iotdb.tsfile.read.common.Path;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- * This class is used to cache <code>DeviceMetaDataCache</code> of tsfile in
IoTDB.
+ * This class is used to cache <code>List<ChunkMetaData></code> of tsfile in
IoTDB. The caching
+ * strategy is LRU.
*/
public class DeviceMetaDataCache {
private static final Logger logger =
LoggerFactory.getLogger(DeviceMetaDataCache.class);
+ private static final IoTDBConfig config =
IoTDBDescriptor.getInstance().getConfig();
- private static final int CACHE_SIZE = 100;
+ private static StorageEngine storageEngine = StorageEngine.getInstance();
+
+ private static final long MEMORY_THRESHOLD_IN_B = (long) (0.3 * config
+ .getAllocateMemoryForRead());
/**
- * key: the file path + deviceId.
+ * key: file path dot deviceId dot sensorId.
+ * <p>
+ * value: chunkMetaData list of one timeseries in the file.
*/
- private LinkedHashMap<String, TsDeviceMetadata> lruCache;
+ private LruLinkedHashMap<String, List<ChunkMetaData>> lruCache;
private AtomicLong cacheHintNum = new AtomicLong();
Review comment:
Hit or hint?
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