After a crash, the database file did not always shrink because old transaction…

After a crash, the database file did not always shrink because old transaction log pages were not removed from the file.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>Various CallableStatement methods could throw a NullPointerException.
+<ul><li>After a crash, the database file did not always shrink because 
+    old transaction log pages were not removed from the file.
+</li><li>Various CallableStatement methods could throw a NullPointerException.
 </li><li>LOB files were not deleted when running DROP ALL OBJECTS.
 </li><li>MS SQL Server compatibility: support "N" in front of string literals ("National Language" strings). Issue 240.
 </li><li>CAST: when converting a string to binary, it is hex encoded (every byte two characters);

h2/src/main/org/h2/store/PageLog.java

@@ -850,4 +850,15 @@ public class PageLog {
         return store.createData();
     }
 
+
+    /**
+     * Get the smallest possible page id used. This is the trunk page if only
+     * appending at the end of the file, or 0.
+     *
+     * @return the smallest possible page.
+     */
+    int getMinPageId() {
+        return pageOut == null ? 0 : pageOut.getMinPageId();
+    }
+
 }

h2/src/main/org/h2/store/PageOutputStream.java

@@ -18,9 +18,11 @@ public class PageOutputStream {
 
     private PageStore store;
     private final Trace trace;
-    private int trunkPageId;
     private final BitField exclude;
+    private final boolean atEnd;
+    private final int minPageId;
 
+    private int trunkPageId;
     private int trunkNext;
     private IntArray reservedPages = new IntArray();
     private PageStreamTrunk trunk;
@@ -31,7 +33,6 @@ public class PageOutputStream {
     private boolean needFlush;
     private boolean writing;
     private int pageCount;
-    private boolean atEnd;
     private int logKey;
 
     /**
@@ -51,6 +52,7 @@ public class PageOutputStream {
         // minus one, because we increment before creating a trunk page
         this.logKey = logKey - 1;
         this.atEnd = atEnd;
+        minPageId = atEnd ? trunkPage : 0;
     }
 
     /**
@@ -209,4 +211,14 @@ public class PageOutputStream {
         }
     }
 
+    /**
+     * Get the smallest possible page id used. This is the trunk page if only
+     * appending at the end of the file, or 0.
+     *
+     * @return the smallest possible page.
+     */
+    int getMinPageId() {
+        return minPageId;
+    }
+
 }

h2/src/main/org/h2/store/PageStore.java

@@ -665,15 +665,21 @@ public class PageStore implements CacheWriter {
             DbException.throwInternalError("not free: " + f);
         }
         Page p = getPage(full);
-        if (p != null) {
+        if (p == null) {
+            freePage(full);
+        } else if (p instanceof PageStreamData || p instanceof PageStreamTrunk) {
+            if (p.getPos() < log.getMinPageId()) {
+                // an old transaction log page
+                // probably a leftover from a crash
+                freePage(full);
+            }
+        } else {
             trace.debug("move " + p.getPos() + " to " + free);
             try {
                 p.moveTo(systemSession, free);
             } finally {
                 changeCount++;
             }
-        } else {
-            freePage(full);
         }
         return true;
     }