From a20dadfb394824ee7a3973cafb9fb641abed5802 Mon Sep 17 00:00:00 2001
From: Andrea Cavalli <andrea@cavallium.it>
Date: Sun, 28 Feb 2021 10:57:16 +0100
Subject: [PATCH] Add low memory scheduler in lucene

---
 .../database/disk/LLLocalKeyValueDatabase.java  |  7 ++++---
 .../database/disk/LLLocalLuceneIndex.java       | 17 +++++++++++++----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/main/java/it/cavallium/dbengine/database/disk/LLLocalKeyValueDatabase.java b/src/main/java/it/cavallium/dbengine/database/disk/LLLocalKeyValueDatabase.java
index f0e6cf0..23e0272 100644
--- a/src/main/java/it/cavallium/dbengine/database/disk/LLLocalKeyValueDatabase.java
+++ b/src/main/java/it/cavallium/dbengine/database/disk/LLLocalKeyValueDatabase.java
@@ -1,6 +1,5 @@
 package it.cavallium.dbengine.database.disk;
 
-import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
 import it.cavallium.dbengine.database.Column;
 import it.cavallium.dbengine.database.LLKeyValueDatabase;
@@ -23,6 +22,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Supplier;
 import org.rocksdb.BlockBasedTableConfig;
 import org.rocksdb.BloomFilter;
 import org.rocksdb.ColumnFamilyDescriptor;
@@ -49,7 +49,8 @@ public class LLLocalKeyValueDatabase implements LLKeyValueDatabase {
 
 	private static final ColumnFamilyDescriptor DEFAULT_COLUMN_FAMILY = new ColumnFamilyDescriptor(
 			RocksDB.DEFAULT_COLUMN_FAMILY);
-	private static Supplier<Scheduler> lowMemorySupplier = Suppliers.memoize(() -> Schedulers.newSingle("db-low-memory"));
+	private static final Supplier<Scheduler> lowMemorySupplier = Suppliers.memoize(() ->
+			Schedulers.newSingle("db-low-memory"))::get;
 
 	private final Scheduler dbScheduler;
 	private final Path dbPath;
@@ -204,7 +205,7 @@ public class LLLocalKeyValueDatabase implements LLKeyValueDatabase {
 			;
 		}
 
-		final org.rocksdb.BloomFilter bloomFilter = new BloomFilter(10, false);
+		final BloomFilter bloomFilter = new BloomFilter(10, false);
 		final BlockBasedTableConfig tableOptions = new BlockBasedTableConfig();
 		tableOptions.setFilterPolicy(bloomFilter);
 		options.setTableFormatConfig(tableOptions);
diff --git a/src/main/java/it/cavallium/dbengine/database/disk/LLLocalLuceneIndex.java b/src/main/java/it/cavallium/dbengine/database/disk/LLLocalLuceneIndex.java
index fcbb8c6..8d18630 100644
--- a/src/main/java/it/cavallium/dbengine/database/disk/LLLocalLuceneIndex.java
+++ b/src/main/java/it/cavallium/dbengine/database/disk/LLLocalLuceneIndex.java
@@ -2,6 +2,7 @@ package it.cavallium.dbengine.database.disk;
 
 import static it.cavallium.dbengine.lucene.LuceneUtils.checkScoringArgumentsValidity;
 
+import com.google.common.base.Suppliers;
 import it.cavallium.dbengine.database.LLDocument;
 import it.cavallium.dbengine.database.LLKeyScore;
 import it.cavallium.dbengine.database.LLLuceneIndex;
@@ -32,6 +33,7 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Supplier;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
@@ -79,16 +81,16 @@ public class LLLocalLuceneIndex implements LLLuceneIndex {
 	 */
 	private static final Scheduler luceneBlockingScheduler = Schedulers.newBoundedElastic(1,
 			Schedulers.DEFAULT_BOUNDED_ELASTIC_QUEUESIZE,
-			"Lucene",
+			"lucene",
 			120,
 			true
 	);
+	private static final Supplier<Scheduler> lowMemorySupplier = Suppliers.memoize(() ->
+			Schedulers.newSingle("lucene-low-memory"))::get;
 	/**
 	 * Lucene query scheduler.
 	 */
-	private final Scheduler luceneQueryScheduler = Schedulers.newBoundedElastic(Runtime
-			.getRuntime()
-			.availableProcessors(), Schedulers.DEFAULT_BOUNDED_ELASTIC_QUEUESIZE, "LuceneQuery", 120, true);
+	private final Scheduler luceneQueryScheduler;
 
 	private final String luceneIndexName;
 	private final SnapshotDeletionPolicy snapshotter;
@@ -141,6 +143,13 @@ public class LLLocalLuceneIndex implements LLLuceneIndex {
 		indexWriterConfig.setSimilarity(getSimilarity());
 		this.indexWriter = new IndexWriter(directory, indexWriterConfig);
 		this.searcherManager = new SearcherManager(indexWriter, false, false, null);
+		if (lowMemory) {
+			this.luceneQueryScheduler = lowMemorySupplier.get();
+		} else {
+			this.luceneQueryScheduler = Schedulers.newBoundedElastic(Runtime
+					.getRuntime()
+					.availableProcessors(), Schedulers.DEFAULT_BOUNDED_ELASTIC_QUEUESIZE, "lucene-query", 60, true);
+		}
 
 		// Create scheduled tasks lifecycle manager
 		this.scheduledTasksLifecycle = new ScheduledTaskLifecycle();