From ab62125ffab3aec42dc0f1a5f71bb32841b8a076 Mon Sep 17 00:00:00 2001
From: Fran <tomaselli.fr@gmail.com>
Date: Sun, 8 Oct 2023 22:24:43 +0200
Subject: [PATCH] sstable list

---
 build.gradle                                  |  6 ++---
 .../tomfran/lsm/tree/LSMTreeBenchmark.java    |  4 ++--
 .../java/com/tomfran/lsm/tree/LSMTree.java    | 23 +++++++++++--------
 .../com/tomfran/lsm/tree/LSMTreeTest.java     |  6 ++---
 4 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/build.gradle b/build.gradle
index 757d7bf..d0874f3 100644
--- a/build.gradle
+++ b/build.gradle
@@ -25,10 +25,10 @@ tasks.test {
 }
 
 jmh {
-//    includes = ['LSMTreeBenchmark.add']
+//    includes = ['SSTableBenchmark.*']
     fork = 1
-    warmupIterations = 5
-    iterations = 10
+    warmupIterations = 3
+    iterations = 5
     benchmarkMode = ['avgt']
     jmhTimeout = '15s'
     jmhVersion = '1.37'
diff --git a/src/jmh/java/com/tomfran/lsm/tree/LSMTreeBenchmark.java b/src/jmh/java/com/tomfran/lsm/tree/LSMTreeBenchmark.java
index 9daefc4..a914cae 100644
--- a/src/jmh/java/com/tomfran/lsm/tree/LSMTreeBenchmark.java
+++ b/src/jmh/java/com/tomfran/lsm/tree/LSMTreeBenchmark.java
@@ -16,8 +16,8 @@
 public class LSMTreeBenchmark {
 
     static final Path DIR = Path.of("tree_benchmark");
-    static final int NUM_ITEMS = 300000;
-    static final int MEMTABLE_SIZE = 1 << 16;
+    static final int NUM_ITEMS = 1000000;
+    static final int MEMTABLE_SIZE = 1 << 18;
 
     static ByteArrayPair[] items;
     static int index = 0;
diff --git a/src/main/java/com/tomfran/lsm/tree/LSMTree.java b/src/main/java/com/tomfran/lsm/tree/LSMTree.java
index ffc3e75..80bd381 100644
--- a/src/main/java/com/tomfran/lsm/tree/LSMTree.java
+++ b/src/main/java/com/tomfran/lsm/tree/LSMTree.java
@@ -26,7 +26,7 @@ public class LSMTree {
 
     Memtable mutableMemtable;
     LinkedList<Memtable> immutableMemtables;
-    SSTable table;
+    LinkedList<SSTable> tables;
     ExecutorService memtableFlusher;
 
     /**
@@ -49,6 +49,7 @@ public LSMTree(int memtableMaxSize, String dataDir) {
 
         mutableMemtable = new Memtable(memtableMaxSize);
         immutableMemtables = new LinkedList<>();
+        tables = new LinkedList<>();
         memtableFlusher = newSingleThreadExecutor();
     }
 
@@ -100,8 +101,9 @@ public byte[] get(byte[] key) {
         }
 
         synchronized (tableLock) {
-            if ((result = table.get(key)) != null)
-                return result;
+            for (SSTable table : tables)
+                if ((result = table.get(key)) != null)
+                    return result;
         }
 
         return null;
@@ -136,13 +138,14 @@ private void flushLastMemtable() {
         String filename = String.format("%s/sst_%d", dataDir, System.currentTimeMillis());
 
         synchronized (tableLock) {
-            if (table == null)
-                table = new SSTable(filename, memtableToFlush.iterator(), DEFAULT_SSTABLE_SAMPLE_SIZE);
-            else {
-                SSTable newTable = SSTable.merge(filename, DEFAULT_SSTABLE_SAMPLE_SIZE, memtableToFlush, table);
-                table.deleteFiles();
-                table = newTable;
-            }
+            tables.addFirst(new SSTable(filename, memtableToFlush.iterator(), DEFAULT_SSTABLE_SAMPLE_SIZE));
+//            if (table == null)
+//                table = ;
+//            else {
+//                SSTable newTable = SSTable.merge(filename, DEFAULT_SSTABLE_SAMPLE_SIZE, memtableToFlush, table);
+//                table.deleteFiles();
+//                table = newTable;
+//            }
         }
 
         // remove flushed memtable from immutable memtables
diff --git a/src/test/java/com/tomfran/lsm/tree/LSMTreeTest.java b/src/test/java/com/tomfran/lsm/tree/LSMTreeTest.java
index a002c0d..2cc0a1a 100644
--- a/src/test/java/com/tomfran/lsm/tree/LSMTreeTest.java
+++ b/src/test/java/com/tomfran/lsm/tree/LSMTreeTest.java
@@ -25,8 +25,8 @@ public void writeFlush() throws InterruptedException {
 
         Thread.sleep(2000);
 
-        assert tree.mutableMemtable.size() == 1 : "mutable memtable size is " + tree.mutableMemtable.size();
-        assert tree.table != null : "table is null";
+        assert tree.mutableMemtable.size() >= 1 : "mutable memtable size is " + tree.mutableMemtable.size();
+        assert !tree.tables.isEmpty() : "table is null";
     }
 
     @Test
@@ -37,7 +37,7 @@ public void writeFlow() throws InterruptedException {
 
         Object2ObjectArrayMap<byte[], byte[]> items = new Object2ObjectArrayMap<>();
 
-        IntStream.range(0, 2 * maxSize).forEach(i -> {
+        IntStream.range(0, 10 * maxSize).forEach(i -> {
             var it = getRandomPair();
             tree.add(it);
             items.put(it.key(), it.value());