MVStore: error compressing an empty page

h2/src/main/org/h2/mvstore/Page.java

@@ -814,13 +814,13 @@ public class Page {
             map.getValueType().write(buff, values, len, false);
         }
         MVStore store = map.getStore();
-        if (store.getCompress()) {
-            Compressor compressor = map.getStore().getCompressor();
         int expLen = buff.position() - compressStart;
+        if (expLen > 16 && store.getCompress()) {
+            Compressor compressor = map.getStore().getCompressor();
             byte[] exp = new byte[expLen];
             buff.position(compressStart).get(exp);
-            byte[] comp = new byte[exp.length * 2];
-            int compLen = compressor.compress(exp, exp.length, comp, 0);
+            byte[] comp = new byte[expLen * 2];
+            int compLen = compressor.compress(exp, expLen, comp, 0);
             if (compLen + DataUtils.getVarIntLen(compLen - expLen) < expLen) {
                 buff.position(typePos).
                     put((byte) (type + DataUtils.PAGE_COMPRESSED));

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

@@ -50,6 +50,7 @@ public class TestMVStore extends TestBase {
     public void test() throws Exception {
         FileUtils.deleteRecursive(getBaseDir(), true);
         FileUtils.createDirectories(getBaseDir());
+        testCompressEmptyPage();
         testCompressed();
         testFileFormatExample();
         testMaxChunkLength();
@@ -106,6 +107,23 @@ public class TestMVStore extends TestBase {
         testLargerThan2G();
     }
     
+    private void testCompressEmptyPage() {
+        String fileName = getBaseDir() + "/testDeletedMap.h3";
+        MVStore store = new MVStore.Builder().
+                cacheSize(100).fileName(fileName).
+                compressData().
+                autoCommitBufferSize(10 * 1024).
+                open();
+        MVMap<String, String> map = store.openMap("test");
+        store.removeMap(map);
+        store.commit();
+        store.close();
+        store = new MVStore.Builder().
+                compressData().
+                open();
+        store.close();
+    }
+    
     private void testCompressed() {
         String fileName = getBaseDir() + "/testCompressed.h3";
         MVStore s = new MVStore.Builder().fileName(fileName).compressData().open();