diff --git a/gradle.properties b/gradle.properties
index ab38e97..68fc37d 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ kotlin.code.style=official
 specifyKotlinAsDependency=false
 
 projectGroup=ru.dbotthepony.kommons
-projectVersion=2.3.1
+projectVersion=2.3.2
 
 guavaDepVersion=33.0.0
 gsonDepVersion=2.8.9
diff --git a/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB.kt b/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB.kt
index dd2c442..f87245d 100644
--- a/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB.kt
+++ b/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB.kt
@@ -14,6 +14,12 @@ abstract class BTreeDB<K, V> : Closeable {
 	abstract val file: File
 	abstract val blockSize: Int
 
+	open operator fun contains(key: K): Boolean {
+		return hasKey(key).get()
+	}
+
+	abstract fun hasKey(key: K): CompletableFuture<Boolean>
+
 	/**
 	 * Reads data at specified [key]
 	 */
diff --git a/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB6.kt b/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB6.kt
index fe900a6..519accb 100644
--- a/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB6.kt
+++ b/src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB6.kt
@@ -127,9 +127,9 @@ class BTreeDB6 private constructor(override val file: File, private val reader:
 		reader.write(headerBuf)
 	}
 
-	private fun doRead(key: ByteKey): KOptional<ByteArray> {
+	private fun searchForBlock(key: ByteKey): Block? {
 		if (rootBlockIndex == INVALID_BLOCK_INDEX) {
-			return KOptional.empty()
+			return null
 		}
 
 		var block = readBlock(rootBlockIndex)
@@ -141,23 +141,35 @@ class BTreeDB6 private constructor(override val file: File, private val reader:
 
 		if (block.type == BlockType.LEAF) {
 			val leaf = LeafData(block)
-			val data = leaf.get(key)
-
-			if (data != null) {
-				val stream = DataInputStream(BlockInputStream(data))
-				val output = ByteArray(stream.readInt())
-				stream.readFully(output)
-				return KOptional(output)
-			}
+			return leaf.get(key)
 		} else if (block.type == BlockType.DATA) {
 			throw IllegalStateException("Hit data block when scanning index")
 		} else if (block.type == BlockType.FREE) {
 			throw IllegalStateException("Hit free block when scanning index")
 		}
 
+		return null
+	}
+
+	private fun doRead(key: ByteKey): KOptional<ByteArray> {
+		val data = searchForBlock(key)
+
+		if (data != null) {
+			val stream = DataInputStream(BlockInputStream(data))
+			val output = ByteArray(stream.readInt())
+			stream.readFully(output)
+			return KOptional(output)
+		}
+
 		return KOptional.empty()
 	}
 
+	override fun hasKey(key: ByteKey): CompletableFuture<Boolean> {
+		return CompletableFuture.supplyAsync(Supplier {
+			searchForBlock(key) != null
+		}, carrier)
+	}
+
 	override fun read(key: ByteKey): CompletableFuture<KOptional<ByteArray>> {
 		return CompletableFuture.supplyAsync(Supplier {
 			doRead(key)