Removed the useless first key in schema cache (#16881)

* refactor

* fix

* fix

* sonar

Author: Caideyipi

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/IoTDBConfig.java

@@ -1051,12 +1051,6 @@ public class IoTDBConfig {
   /** Policy of DataNodeSchemaCache eviction */
   private String dataNodeSchemaCacheEvictionPolicy = "FIFO";
 
-  /**
-   * Threshold for cache size in mayEvict. When cache size exceeds this threshold, the system will
-   * compute total memory in each eviction iteration to ensure accurate memory management.
-   */
-  private int cacheEvictionMemoryComputationThreshold = 20;
-
   private int schemaThreadCount = 5;
 
   private String readConsistencyLevel = "strong";
@@ -3511,15 +3505,6 @@ public void setDataNodeSchemaCacheEvictionPolicy(String dataNodeSchemaCacheEvict
     this.dataNodeSchemaCacheEvictionPolicy = dataNodeSchemaCacheEvictionPolicy;
   }
 
-  public int getCacheEvictionMemoryComputationThreshold() {
-    return cacheEvictionMemoryComputationThreshold;
-  }
-
-  public void setCacheEvictionMemoryComputationThreshold(
-      int cacheEvictionMemoryComputationThreshold) {
-    this.cacheEvictionMemoryComputationThreshold = cacheEvictionMemoryComputationThreshold;
-  }
-
   public int getSchemaThreadCount() {
     return schemaThreadCount;
   }

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/IoTDBDescriptor.java

@@ -1097,12 +1097,6 @@ public void loadProperties(TrimProperties properties) throws BadNodeUrlException
         properties.getProperty(
             "datanode_schema_cache_eviction_policy", conf.getDataNodeSchemaCacheEvictionPolicy()));
 
-    conf.setCacheEvictionMemoryComputationThreshold(
-        Integer.parseInt(
-            properties.getProperty(
-                "cache_eviction_memory_computation_threshold",
-                String.valueOf(conf.getCacheEvictionMemoryComputationThreshold()))));
-
     conf.setSchemaThreadCount(
         Integer.parseInt(
             properties.getProperty(
@@ -2088,13 +2082,6 @@ public synchronized void loadHotModifiedProps(TrimProperties properties)
       // update trusted_uri_pattern
       loadTrustedUriPattern(properties);
 
-      // update cache_eviction_memory_computation_threshold
-      conf.setCacheEvictionMemoryComputationThreshold(
-          Integer.parseInt(
-              properties.getProperty(
-                  "cache_eviction_memory_computation_threshold",
-                  String.valueOf(conf.getCacheEvictionMemoryComputationThreshold()))));
-
       // tvlist_sort_threshold
       conf.setTVListSortThreshold(
           Integer.parseInt(

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/protocol/rest/v2/impl/RestApiServiceImpl.java

@@ -111,7 +111,7 @@ public Response executeFastLastQueryStatement(
 
       PartialPath prefixPath =
           new PartialPath(prefixPathList.getPrefixPaths().toArray(new String[0]));
-      final Map<String, Map<PartialPath, Map<String, TimeValuePair>>> resultMap = new HashMap<>();
+      final Map<PartialPath, Map<String, TimeValuePair>> resultMap = new HashMap<>();
 
       final String prefixString = prefixPath.toString();
       for (ISchemaRegion region : SchemaEngine.getInstance().getAllSchemaRegions()) {
@@ -170,21 +170,18 @@ public Response executeFastLastQueryStatement(
       List<Object> timeseries = new ArrayList<>();
       List<Object> valueList = new ArrayList<>();
       List<Object> dataTypeList = new ArrayList<>();
-      for (Map.Entry<String, Map<PartialPath, Map<String, TimeValuePair>>> entry :
+      for (final Map.Entry<PartialPath, Map<String, TimeValuePair>> device2MeasurementLastEntry :
           resultMap.entrySet()) {
-        for (final Map.Entry<PartialPath, Map<String, TimeValuePair>> device2MeasurementLastEntry :
-            entry.getValue().entrySet()) {
-          final String deviceWithSeparator =
-              device2MeasurementLastEntry.getKey() + TsFileConstant.PATH_SEPARATOR;
-          for (Map.Entry<String, TimeValuePair> measurementEntry :
-              device2MeasurementLastEntry.getValue().entrySet()) {
-            final TimeValuePair tvPair = measurementEntry.getValue();
-            if (tvPair != DeviceLastCache.EMPTY_TIME_VALUE_PAIR) {
-              valueList.add(tvPair.getValue().getStringValue());
-              dataTypeList.add(tvPair.getValue().getDataType().name());
-              targetDataSet.addTimestampsItem(tvPair.getTimestamp());
-              timeseries.add(deviceWithSeparator + measurementEntry.getKey());
-            }
+        final String deviceWithSeparator =
+            device2MeasurementLastEntry.getKey() + TsFileConstant.PATH_SEPARATOR;
+        for (Map.Entry<String, TimeValuePair> measurementEntry :
+            device2MeasurementLastEntry.getValue().entrySet()) {
+          final TimeValuePair tvPair = measurementEntry.getValue();
+          if (tvPair != DeviceLastCache.EMPTY_TIME_VALUE_PAIR) {
+            valueList.add(tvPair.getValue().getStringValue());
+            dataTypeList.add(tvPair.getValue().getDataType().name());
+            targetDataSet.addTimestampsItem(tvPair.getTimestamp());
+            timeseries.add(deviceWithSeparator + measurementEntry.getKey());
           }
         }
       }

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/protocol/thrift/impl/ClientRPCServiceImpl.java

@@ -818,7 +818,7 @@ public TSExecuteStatementResp executeFastLastDataQueryForOnePrefixPath(
                     "The \"executeFastLastDataQueryForOnePrefixPath\" dos not support wildcards."));
       }
 
-      final Map<String, Map<PartialPath, Map<String, TimeValuePair>>> resultMap = new HashMap<>();
+      final Map<PartialPath, Map<String, TimeValuePair>> resultMap = new HashMap<>();
       int sensorNum = 0;
 
       final String prefixString = prefixPath.toString();
@@ -839,25 +839,22 @@ public TSExecuteStatementResp executeFastLastDataQueryForOnePrefixPath(
       // 2.2 all sensors hit cache, return response ~= 20ms
       final TsBlockBuilder builder = LastQueryUtil.createTsBlockBuilder(sensorNum);
 
-      for (final Map.Entry<String, Map<PartialPath, Map<String, TimeValuePair>>> result :
+      for (final Map.Entry<PartialPath, Map<String, TimeValuePair>> device2MeasurementLastEntry :
           resultMap.entrySet()) {
-        for (final Map.Entry<PartialPath, Map<String, TimeValuePair>> device2MeasurementLastEntry :
-            result.getValue().entrySet()) {
-          final String deviceWithSeparator =
-              device2MeasurementLastEntry.getKey() + TsFileConstant.PATH_SEPARATOR;
-          for (final Map.Entry<String, TimeValuePair> measurementLastEntry :
-              device2MeasurementLastEntry.getValue().entrySet()) {
-            final TimeValuePair tvPair = measurementLastEntry.getValue();
-            if (tvPair != DeviceLastCache.EMPTY_TIME_VALUE_PAIR) {
-              LastQueryUtil.appendLastValue(
-                  builder,
-                  tvPair.getTimestamp(),
-                  new Binary(
-                      deviceWithSeparator + measurementLastEntry.getKey(),
-                      TSFileConfig.STRING_CHARSET),
-                  tvPair.getValue().getStringValue(),
-                  tvPair.getValue().getDataType().name());
-            }
+        final String deviceWithSeparator =
+            device2MeasurementLastEntry.getKey() + TsFileConstant.PATH_SEPARATOR;
+        for (final Map.Entry<String, TimeValuePair> measurementLastEntry :
+            device2MeasurementLastEntry.getValue().entrySet()) {
+          final TimeValuePair tvPair = measurementLastEntry.getValue();
+          if (tvPair != DeviceLastCache.EMPTY_TIME_VALUE_PAIR) {
+            LastQueryUtil.appendLastValue(
+                builder,
+                tvPair.getTimestamp(),
+                new Binary(
+                    deviceWithSeparator + measurementLastEntry.getKey(),
+                    TSFileConfig.STRING_CHARSET),
+                tvPair.getValue().getStringValue(),
+                tvPair.getValue().getDataType().name());
           }
         }
       }

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/protocol/thrift/impl/DataNodeInternalRPCServiceImpl.java

@@ -537,7 +537,7 @@ public TSStatus invalidatePartitionCache(final TInvalidateCacheReq req) {
 
   @Override
   public TSStatus invalidateLastCache(final String database) {
-    DataNodeSchemaCache.getInstance().invalidateDatabaseLastCache(database);
+    DataNodeSchemaCache.getInstance().getDeviceSchemaCache().invalidateLastCache();
     return new TSStatus(TSStatusCode.SUCCESS_STATUS.getStatusCode());
   }
 
@@ -546,7 +546,7 @@ public TSStatus invalidateSchemaCache(final TInvalidateCacheReq req) {
     DataNodeSchemaCache.getInstance().takeWriteLock();
     try {
       // req.getFullPath() is a database path
-      DataNodeSchemaCache.getInstance().getDeviceSchemaCache().invalidate(req.getFullPath());
+      DataNodeSchemaCache.getInstance().getDeviceSchemaCache().invalidateAll();
       ClusterTemplateManager.getInstance().invalid(req.getFullPath());
       LOGGER.info("Schema cache of {} has been invalidated", req.getFullPath());
       return new TSStatus(TSStatusCode.SUCCESS_STATUS.getStatusCode());

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/analyze/cache/schema/DataNodeSchemaCache.java

@@ -306,13 +306,6 @@ public void invalidateLastCache(final PartialPath path) {
     deviceSchemaCache.invalidateLastCache(path.getDevicePath(), path.getMeasurement());
   }
 
-  public void invalidateDatabaseLastCache(final String database) {
-    if (!CommonDescriptor.getInstance().getConfig().isLastCacheEnable()) {
-      return;
-    }
-    deviceSchemaCache.invalidateLastCache(database);
-  }
-
   /**
    * Update the {@link DeviceLastCache} in writing. If a measurement is with all {@code null}s, its
    * {@link TimeValuePair}[] shall be {@code null}. For correctness, this will put the {@link