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Posted to commits@iotdb.apache.org by ji...@apache.org on 2025/10/17 04:01:47 UTC
(iotdb) branch cache_non_exist_timeseries_metadata created (now 1cd27fa2c17)
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jiangtian pushed a change to branch cache_non_exist_timeseries_metadata
in repository https://gitbox.apache.org/repos/asf/iotdb.git
at 1cd27fa2c17 Cache non-exist timeseries metadata to reduce IO
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new 1cd27fa2c17 Cache non-exist timeseries metadata to reduce IO
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(iotdb) 01/01: Cache non-exist timeseries metadata to reduce IO
Posted by ji...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
jiangtian pushed a commit to branch cache_non_exist_timeseries_metadata
in repository https://gitbox.apache.org/repos/asf/iotdb.git
commit 1cd27fa2c17b3f5d38a30ca42b2c9bc7819b6b14
Author: Tian Jiang <jt...@163.com>
AuthorDate: Fri Oct 17 12:01:35 2025 +0800
Cache non-exist timeseries metadata to reduce IO
---
.../apache/iotdb/db/conf/DataNodeMemoryConfig.java | 18 +++
.../buffer/TimeSeriesMetadataCache.java | 19 ++-
.../buffer/TimeSeriesMetadataCacheTest.java | 139 +++++++++++++++++++++
.../conf/iotdb-system.properties.template | 5 +
4 files changed, 180 insertions(+), 1 deletion(-)
diff --git a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/DataNodeMemoryConfig.java b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/DataNodeMemoryConfig.java
index efb6758066f..d07bcc61d74 100644
--- a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/DataNodeMemoryConfig.java
+++ b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/DataNodeMemoryConfig.java
@@ -56,6 +56,12 @@ public class DataNodeMemoryConfig {
/** whether to cache metadata(ChunkMetaData and TsFileMetaData) or not. */
private boolean metaDataCacheEnable = true;
+ /**
+ * If a timeseries is not found in a TsFile, also cache a placeholder to indicate the
+ * non-existence.
+ */
+ private boolean mayCacheNonExistSeries = true;
+
/** How many threads can concurrently execute query statement. When <= 0, use CPU core number. */
private int queryThreadCount = Runtime.getRuntime().availableProcessors();
@@ -407,6 +413,10 @@ public class DataNodeMemoryConfig {
Boolean.parseBoolean(
properties.getProperty(
"meta_data_cache_enable", Boolean.toString(isMetaDataCacheEnable()))));
+ setMayCacheNonExistSeries(
+ Boolean.parseBoolean(
+ properties.getProperty(
+ "may_cache_nonexist_series", Boolean.toString(isMetaDataCacheEnable()))));
setQueryThreadCount(
Integer.parseInt(
properties.getProperty("query_thread_count", Integer.toString(getQueryThreadCount()))));
@@ -560,6 +570,14 @@ public class DataNodeMemoryConfig {
this.metaDataCacheEnable = metaDataCacheEnable;
}
+ public boolean isMayCacheNonExistSeries() {
+ return mayCacheNonExistSeries;
+ }
+
+ public void setMayCacheNonExistSeries(boolean mayCacheNonExistSeries) {
+ this.mayCacheNonExistSeries = mayCacheNonExistSeries;
+ }
+
public int getQueryThreadCount() {
return queryThreadCount;
}
diff --git a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCache.java b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCache.java
index c3fef67b5f1..052d4b0b34f 100644
--- a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCache.java
+++ b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCache.java
@@ -35,10 +35,13 @@ import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.Weigher;
import org.apache.tsfile.common.constant.TsFileConstant;
+import org.apache.tsfile.enums.TSDataType;
import org.apache.tsfile.file.metadata.IDeviceID;
import org.apache.tsfile.file.metadata.TimeseriesMetadata;
+import org.apache.tsfile.file.metadata.statistics.Statistics;
import org.apache.tsfile.read.TsFileSequenceReader;
import org.apache.tsfile.utils.BloomFilter;
+import org.apache.tsfile.utils.PublicBAOS;
import org.apache.tsfile.utils.RamUsageEstimator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@@ -69,6 +72,14 @@ public class TimeSeriesMetadataCache {
IoTDBDescriptor.getInstance().getMemoryConfig();
private static final IMemoryBlock CACHE_MEMORY_BLOCK;
private static final boolean CACHE_ENABLE = memoryConfig.isMetaDataCacheEnable();
+ private static final TimeseriesMetadata NULL_EXISTS_CACHE_PLACE_HOLDER =
+ new TimeseriesMetadata(
+ (byte) 0,
+ 0,
+ "",
+ TSDataType.INT32,
+ Statistics.getStatsByType(TSDataType.INT32),
+ new PublicBAOS());
private final Cache<TimeSeriesMetadataCacheKey, TimeseriesMetadata> lruCache;
@@ -188,6 +199,9 @@ public class TimeSeriesMetadataCache {
DEBUG_LOGGER.info("TimeSeries meta data {} is filter by bloomFilter!", key);
}
loadBloomFilterTime = System.nanoTime() - loadBloomFilterStartTime;
+ if (memoryConfig.isMayCacheNonExistSeries()) {
+ lruCache.put(key, NULL_EXISTS_CACHE_PLACE_HOLDER);
+ }
return null;
}
@@ -217,10 +231,13 @@ public class TimeSeriesMetadataCache {
}
}
}
- if (timeseriesMetadata == null) {
+ if (timeseriesMetadata == null || timeseriesMetadata == NULL_EXISTS_CACHE_PLACE_HOLDER) {
if (debug) {
DEBUG_LOGGER.info("The file doesn't have this time series {}.", key);
}
+ if (timeseriesMetadata == null && memoryConfig.isMayCacheNonExistSeries()) {
+ lruCache.put(key, NULL_EXISTS_CACHE_PLACE_HOLDER);
+ }
return null;
} else {
if (debug) {
diff --git a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCacheTest.java b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCacheTest.java
new file mode 100644
index 00000000000..49fb6c555f6
--- /dev/null
+++ b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCacheTest.java
@@ -0,0 +1,139 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.db.storageengine.buffer;
+
+import org.apache.iotdb.db.conf.IoTDBDescriptor;
+import org.apache.iotdb.db.queryengine.execution.fragment.QueryContext;
+import org.apache.iotdb.db.storageengine.buffer.TimeSeriesMetadataCache.TimeSeriesMetadataCacheKey;
+import org.apache.iotdb.db.storageengine.dataregion.tsfile.TsFileID;
+
+import org.apache.tsfile.enums.TSDataType;
+import org.apache.tsfile.exception.write.WriteProcessException;
+import org.apache.tsfile.file.metadata.IDeviceID;
+import org.apache.tsfile.file.metadata.IDeviceID.Factory;
+import org.apache.tsfile.write.TsFileWriter;
+import org.apache.tsfile.write.record.TSRecord;
+import org.apache.tsfile.write.schema.MeasurementSchema;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class TimeSeriesMetadataCacheTest {
+
+ private void testCachePlaceHolderInternal() throws IOException, WriteProcessException {
+ TimeSeriesMetadataCache.getInstance().clear();
+ File file = new File("target/test.tsfile");
+ TsFileID tsFileID = new TsFileID();
+
+ int deviceCnt = 100;
+ int seriesPerDevice = 100;
+ List<IDeviceID> deviceIDList = new ArrayList<>();
+ for (int i = 0; i < deviceCnt; i++) {
+ deviceIDList.add(Factory.DEFAULT_FACTORY.create("root.d" + i));
+ }
+
+ try (TsFileWriter tsFileWriter = new TsFileWriter(file)) {
+ // 100*100 series in the file
+
+ for (int i = 0; i < deviceCnt; i++) {
+ for (int j = 0; j < seriesPerDevice; j++) {
+ tsFileWriter.registerTimeseries(
+ deviceIDList.get(i), new MeasurementSchema("s" + j, TSDataType.INT32));
+ }
+ }
+ for (int i = 0; i < deviceCnt; i++) {
+ TSRecord rec = new TSRecord(deviceIDList.get(i), 0);
+ for (int j = 0; j < seriesPerDevice; j++) {
+ rec.addPoint("s" + j, 0);
+ }
+ tsFileWriter.writeRecord(rec);
+ }
+ tsFileWriter.close();
+
+ // read 100*200 series each 10 times in the file
+ TimeSeriesMetadataCache.getInstance().clear();
+ long start = System.currentTimeMillis();
+ QueryContext queryContext = new QueryContext();
+ // put k in outer loop
+ for (int k = 0; k < 10; k++) {
+ for (int i = 0; i < deviceCnt; i++) {
+ for (int j = 0; j < seriesPerDevice; j++) {
+ TimeSeriesMetadataCacheKey key =
+ new TimeSeriesMetadataCacheKey(tsFileID, deviceIDList.get(i), "s" + j);
+ TimeSeriesMetadataCache.getInstance()
+ .get(file.getPath(), key, Collections.EMPTY_SET, true, false, queryContext);
+ }
+ }
+ }
+ System.out.println("time cost with outer k: " + (System.currentTimeMillis() - start));
+
+ TimeSeriesMetadataCache.getInstance().clear();
+ start = System.currentTimeMillis();
+ queryContext = new QueryContext();
+ // put k in inner loop
+ for (int i = 0; i < deviceCnt; i++) {
+ for (int j = 0; j < seriesPerDevice; j++) {
+ TimeSeriesMetadataCacheKey key =
+ new TimeSeriesMetadataCacheKey(tsFileID, deviceIDList.get(i), "s" + j);
+ for (int k = 0; k < 10; k++) {
+ TimeSeriesMetadataCache.getInstance()
+ .get(file.getPath(), key, Collections.EMPTY_SET, true, false, queryContext);
+ }
+ }
+ }
+ System.out.println("time cost with inner k: " + (System.currentTimeMillis() - start));
+ } finally {
+ file.delete();
+ }
+ }
+
+ @Ignore("Performance")
+ @Test
+ public void testCachePlaceHolder() throws IOException, WriteProcessException {
+ boolean mayCacheNonExistSeries =
+ IoTDBDescriptor.getInstance().getMemoryConfig().isMayCacheNonExistSeries();
+ try {
+ System.out.println("warming up");
+ System.out.println("Do not cache non-exist series");
+ IoTDBDescriptor.getInstance().getMemoryConfig().setMayCacheNonExistSeries(false);
+ testCachePlaceHolderInternal();
+ System.out.println("Cache non-exist series");
+ IoTDBDescriptor.getInstance().getMemoryConfig().setMayCacheNonExistSeries(true);
+ testCachePlaceHolderInternal();
+
+ System.out.println("actual test");
+ System.out.println("Do not cache non-exist series");
+ IoTDBDescriptor.getInstance().getMemoryConfig().setMayCacheNonExistSeries(false);
+ testCachePlaceHolderInternal();
+ System.out.println("Cache non-exist series");
+ IoTDBDescriptor.getInstance().getMemoryConfig().setMayCacheNonExistSeries(true);
+ testCachePlaceHolderInternal();
+ } finally {
+ IoTDBDescriptor.getInstance()
+ .getMemoryConfig()
+ .setMayCacheNonExistSeries(mayCacheNonExistSeries);
+ }
+ }
+}
diff --git a/iotdb-core/node-commons/src/assembly/resources/conf/iotdb-system.properties.template b/iotdb-core/node-commons/src/assembly/resources/conf/iotdb-system.properties.template
index 207c0507093..78c7701b4f7 100644
--- a/iotdb-core/node-commons/src/assembly/resources/conf/iotdb-system.properties.template
+++ b/iotdb-core/node-commons/src/assembly/resources/conf/iotdb-system.properties.template
@@ -1035,6 +1035,11 @@ read_consistency_level=strong
# Datatype: boolean
meta_data_cache_enable=true
+# Whether to cache a placeholder for non-exist series.
+# effectiveMode: restart
+# Datatype: boolean
+may_cache_nonexist_series=true
+
# Read memory Allocation Ratio: BloomFilterCache : ChunkCache : TimeSeriesMetadataCache : Coordinator : Operators : DataExchange : timeIndex in TsFileResourceList : others.
# The parameter form is a:b:c:d:e:f:g:h, where a, b, c, d, e, f, g and h are integers. for example: 1:1:1:1:1:1:1:1 , 1:100:200:50:200:200:200:50
# effectiveMode: restart