A persistent multi-version map (work in progress) - allow reading old versions…

A persistent multi-version map (work in progress) - allow reading old versions after storing; in-memory mode

h2/src/test/org/h2/test/store/RtreeMap.java

@@ -104,7 +104,7 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
             for (int i = 0; i < p.getKeyCount(); i++) {
                 if (contains(p, i, key)) {
                     Page c = p.getChildPage(i);
-                    long oldSize = c.getTotalSize();
+                    long oldSize = c.getTotalCount();
                     Page c2 = remove(c, writeVersion, key);
                     if (c2 == null) {
                         // this child was deleted
@@ -114,7 +114,7 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
                         }
                         p = p.copyOnWrite(writeVersion);
                         p.remove(i);
-                    } else if (oldSize != c2.getTotalSize()) {
+                    } else if (oldSize != c2.getTotalCount()) {
                         p = p.copyOnWrite(writeVersion);
                         Object oldBounds = p.getKey(i);
                         if (!keyType.isInside(key, oldBounds)) {
@@ -197,21 +197,22 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
             Object[] keys = { key };
             Object[] values = { value };
             p = Page.create(this, writeVersion, 1,
-                    keys, values, null, null, 1, 0);
+                    keys, values, null, null, null, 1, 0);
             return p;
         }
         if (p.getKeyCount() > maxPageSize) {
             // only possible if this is the root, else we would have split earlier
             // (this requires maxPageSize is fixed)
             p = p.copyOnWrite(writeVersion);
-            long totalSize = p.getTotalSize();
+            long totalCount = p.getTotalCount();
             Page split = split(p, writeVersion);
             Object[] keys = { getBounds(p), getBounds(split) };
             long[] children = { p.getPos(), split.getPos(), 0 };
-            long[] childrenSize = { p.getTotalSize(), split.getTotalSize(), 0 };
+            Page[] childrenPages = { p, split, null };
+            long[] counts = { p.getTotalCount(), split.getTotalCount(), 0 };
             p = Page.create(this, writeVersion, 2,
-                    keys, null, children, childrenSize,
-                    totalSize, 0);
+                    keys, null, children, childrenPages, counts,
+                    totalCount, 0);
             // now p is a node; continues
         } else if (p.isLeaf()) {
             p = p.copyOnWrite(writeVersion);
@@ -246,7 +247,7 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
             p = p.copyOnWrite(writeVersion);
             p.setKey(index, getBounds(c));
             p.setChild(index, c);
-            p.insertNode(index, getBounds(split), split.getPos(), split.getTotalSize());
+            p.insertNode(index, getBounds(split), split);
             // now we are not sure where to add
             return add(p, writeVersion, key, value, maxPageSize);
         }
@@ -360,8 +361,9 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
     private Page newPage(boolean leaf, long writeVersion) {
         Object[] values = leaf ? new Object[4] : null;
         long[] c = leaf ? null : new long[1];
+        Page[] cp = leaf ? null : new Page[1];
         return Page.create(this, writeVersion, 0,
-                new Object[4], values, c, c, 0, 0);
+                new Object[4], values, c, cp, c, 0, 0);
     }
 
     private static void move(Page source, Page target, int sourceIndex) {
@@ -370,9 +372,8 @@ public class RtreeMap<K, V> extends BtreeMap<K, V> {
             Object v = source.getValue(sourceIndex);
             target.insertLeaf(0, k, v);
         } else {
-            long c = source.getChildPage(sourceIndex).getPos();
-            long count = source.getCounts(sourceIndex);
-            target.insertNode(0, k, c, count);
+            Page c = source.getChildPage(sourceIndex);
+            target.insertNode(0, k, c);
         }
         source.remove(sourceIndex);
     }

h2/src/test/org/h2/test/store/TestBtreeMapStore.java

@@ -53,6 +53,7 @@ public class TestBtreeMapStore extends TestBase {
         testRollbackInMemory();
         testRollbackStored();
         testMeta();
+        testInMemory();
         testLargeImport();
         testBtreeStore();
         testDefragment();
@@ -95,9 +96,9 @@ public class TestBtreeMapStore extends TestBase {
         s.setRetainChunk(0);
         long old2 = s.store();
 
-        // TODO keep old version after storing
-        // assertEquals("Hello", mOld.get("1"));
-        // assertEquals("World", mOld.get("2"));
+        // the old version is still available
+        assertEquals("Hello", mOld.get("1"));
+        assertEquals("World", mOld.get("2"));
 
         m.put("1",  "Hi");
         m.remove("2");
@@ -528,6 +529,36 @@ public class TestBtreeMapStore extends TestBase {
         s.close();
     }
 
+    private void testInMemory() {
+        for (int j = 0; j < 1; j++) {
+            BtreeMapStore s = openStore(null);
+            // s.setMaxPageSize(10);
+            // long t;
+            int len = 100;
+            // TreeMap<Integer, String> m = new TreeMap<Integer, String>();
+            // HashMap<Integer, String> m = New.hashMap();
+            BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+            // t = System.currentTimeMillis();
+            for (int i = 0; i < len; i++) {
+                m.put(i, "Hello World");
+            }
+            // System.out.println("put: " + (System.currentTimeMillis() - t));
+            // t = System.currentTimeMillis();
+            for (int i = 0; i < len; i++) {
+                assertEquals("Hello World", m.get(i));
+            }
+            // System.out.println("get: " + (System.currentTimeMillis() - t));
+            // t = System.currentTimeMillis();
+            for (int i = 0; i < len; i++) {
+                m.remove(i);
+            }
+            // System.out.println("remove: " + (System.currentTimeMillis() - t));
+            // System.out.println();
+            assertEquals(0, m.size());
+            s.close();
+        }
+    }
+
     private void testLargeImport() {
         String fileName = getBaseDir() + "/testImport.h3";
         int len = 1000;

h2/src/tools/org/h2/dev/store/btree/BtreeMap.java

@@ -75,7 +75,7 @@ public class BtreeMap<K, V> {
             Object[] keys = { key };
             Object[] values = { value };
             p = Page.create(this, writeVersion, 1,
-                    keys, values, null, null, 1, 0);
+                    keys, values, null, null, null, 1, 0);
             return p;
         }
         if (p.getKeyCount() > maxPageSize) {
@@ -83,14 +83,15 @@ public class BtreeMap<K, V> {
             // (this requires maxPageSize is fixed)
             p = p.copyOnWrite(writeVersion);
             int at = p.getKeyCount() / 2;
-            long totalSize = p.getTotalSize();
+            long totalCount = p.getTotalCount();
             Object k = p.getKey(at);
             Page split = p.split(at);
             Object[] keys = { k };
             long[] children = { p.getPos(), split.getPos() };
-            long[] childrenSize = { p.getTotalSize(), split.getTotalSize() };
+            Page[] childrenPages = { p, split };
+            long[] counts = { p.getTotalCount(), split.getTotalCount() };
             p = Page.create(this, writeVersion, 1,
-                    keys, null, children, childrenSize, totalSize, 0);
+                    keys, null, children, childrenPages, counts, totalCount, 0);
             // now p is a node; insert continues
         } else if (p.isLeaf()) {
             int index = p.binarySearch(key);
@@ -119,13 +120,13 @@ public class BtreeMap<K, V> {
             Page split = c.split(at);
             p = p.copyOnWrite(writeVersion);
             p.setChild(index, split);
-            p.insertNode(index, k, c.getPos(), c.getTotalSize());
+            p.insertNode(index, k, c);
             // now we are not sure where to add
             return put(p, writeVersion, key, value, maxPageSize);
         }
-        long oldSize = c.getTotalSize();
+        long oldSize = c.getTotalCount();
         Page c2 = put(c, writeVersion, key, value, maxPageSize);
-        if (c != c2 || oldSize != c2.getTotalSize()) {
+        if (c != c2 || oldSize != c2.getTotalCount()) {
             p = p.copyOnWrite(writeVersion);
             p.setChild(index, c2);
         }
@@ -354,7 +355,7 @@ public class BtreeMap<K, V> {
             index++;
         }
         Page c = p.getChildPage(index);
-        long oldSize = c.getTotalSize();
+        long oldCount = c.getTotalCount();
         Page c2 = remove(c, writeVersion, key);
         if (c2 == null) {
             // this child was deleted
@@ -364,7 +365,7 @@ public class BtreeMap<K, V> {
                 removePage(p);
                 p = p.getChildPage(0);
             }
-        } else if (oldSize != c2.getTotalSize()) {
+        } else if (oldCount != c2.getTotalCount()) {
             p = p.copyOnWrite(writeVersion);
             p.setChild(index, c2);
         }
@@ -562,7 +563,7 @@ public class BtreeMap<K, V> {
     }
 
     public long getSize() {
-        return root == null ? 0 : root.getTotalSize();
+        return root == null ? 0 : root.getTotalCount();
     }
 
     public boolean equals(Object o) {

h2/src/tools/org/h2/dev/store/btree/BtreeMapStore.java

@@ -11,7 +11,6 @@ import java.io.StringReader;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Collections;
 import java.util.Comparator;
@@ -53,7 +52,6 @@ TODO:
 - support large binaries
 - support stores that span multiple files (chunks stored in other files)
 - triggers
-- compare with newest version of IndexedDb
 - support database version / schema version
 - implement more counted b-tree (skip, get positions)
 - merge pages if small
@@ -83,10 +81,7 @@ public class BtreeMapStore {
     private int blockSize = 4 * 1024;
     private long rootChunkStart;
 
-    private int tempPageId;
     private Map<Long, Page> cache = CacheLIRS.newInstance(readCacheSize, 2048);
-    private HashMap<Long, Page> temp = New.hashMap();
-    private Page[] tempCache = new Page[64];
 
     private int lastChunkId;
     private HashMap<Integer, Chunk> chunks = New.hashMap();
@@ -134,7 +129,7 @@ public class BtreeMapStore {
     /**
      * Open a tree store.
      *
-     * @param fileName the file name
+     * @param fileName the file name (null for in-memory)
      * @param mapFactory the map factory
      * @return the store
      */
@@ -306,6 +301,9 @@ public class BtreeMapStore {
 
     private void open() {
         meta = new BtreeMap<String, String>(this, 0, "meta", STRING_TYPE, STRING_TYPE, 0);
+        if (fileName == null) {
+            return;
+        }
         FileUtils.createDirectories(FileUtils.getParent(fileName));
         try {
             log("file open");
@@ -397,8 +395,6 @@ public class BtreeMapStore {
                 for (BtreeMap<?, ?> m : New.arrayList(maps.values())) {
                     m.close();
                 }
-                temp.clear();
-                Arrays.fill(tempCache, null);
                 meta = null;
                 compressor = null;
                 chunks.clear();
@@ -623,21 +619,6 @@ public class BtreeMapStore {
         return set.size() * blockSize;
     }
 
-    /**
-     * Register a page and get the next temporary page id.
-     *
-     * @param p the new page
-     * @return the page id
-     */
-    long registerTempPage(Page p) {
-        long pos = --tempPageId;
-        // use -pos so the Long cache can be used
-        temp.put(-pos, p);
-        int index = (int) pos & (tempCache.length - 1);
-        tempCache[index] = p;
-        return pos;
-    }
-
     /**
      * Check whether there are any unsaved changes.
      *
@@ -833,15 +814,6 @@ public class BtreeMapStore {
      * @return the page
      */
     Page readPage(BtreeMap<?, ?> map, long pos) {
-        if (pos < 0) {
-            int index = (int) pos & (tempCache.length - 1);
-            Page p = tempCache[index];
-            if (p == null || p.getPos() != pos) {
-                p = temp.get(-pos);
-                tempCache[index] = p;
-            }
-            return p;
-        }
         Page p = cache.get(pos);
         if (p == null) {
             long filePos = getFilePosition(pos);
@@ -1033,9 +1005,6 @@ public class BtreeMapStore {
             m.revertTemp();
         }
         mapsChanged.clear();
-        temp.clear();
-        Arrays.fill(tempCache, null);
-        tempPageId = 0;
     }
 
     /**