Garbage collection of unused chunks should be faster still

h2/src/docsrc/html/changelog.html

@@ -37,6 +37,8 @@ Change Log
 </li>
 <li>MVStoreTool: add "repair" feature.
 </li>
+<li>Garbage collection of unused chunks should be faster still.
+</li>
 </ul>
 
 <h2>Version 1.4.192 Beta (2016-05-26)</h2>

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

@@ -1056,8 +1056,11 @@ public class MVStore {
         long time = getTimeSinceCreation();
         int freeDelay = retentionTime / 10;
         if (time >= lastFreeUnusedChunks + freeDelay) {
+            // set early in case it fails (out of memory or so)
             lastFreeUnusedChunks = time;
             freeUnusedChunks();
+            // set it here as well, to avoid calling it often if it was slow
+            lastFreeUnusedChunks = getTimeSinceCreation();
         }
         int currentUnsavedPageCount = unsavedMemory;
         long storeVersion = currentStoreVersion;
@@ -1514,6 +1517,9 @@ public class MVStore {
      * @param minPercent the minimum percentage to save
      */
     private void shrinkFileIfPossible(int minPercent) {
+        if (fileStore.isReadOnly()) {
+            return;
+        }
         long end = getFileLengthInUse();
         long fileSize = fileStore.size();
         if (end >= fileSize) {
@@ -2660,6 +2666,15 @@ public class MVStore {
         return cache;
     }
 
+    /**
+     * Whether the store is read-only.
+     *
+     * @return true if it is
+     */
+    public boolean isReadOnly() {
+        return fileStore == null ? false : fileStore.isReadOnly();
+    }
+
     /**
      * A background writer thread to automatically store changes from time to
      * time.