Reuse space after deleting or updating many rows in a b-tree index.

h2/src/docsrc/html/changelog.html

@@ -18,9 +18,12 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>When using Turkish as the default locale, sometimes columns could not be accessed 
-    using the lowercase column alias or name. This affects locales where String.toUpper("a...z") does not 
-    result in "A...Z", which is so far only Turkish, where "i".toUpperCase() is "I" with dot above.
+<ul><li>When deleting or updating many rows in a table, the space in the index
+    file was not re-used in the default mode (persistent database, b-tree index,
+    LOG=1). This caused the index file to grow over time. Workarounds were to
+    delete and re-created the index file, alter the table (add a remove a column), 
+    or use LOG=2. To disable the change, set the system property 
+    h2.reuseSpaceBtreeIndex to false.
 </li><li>Identifiers with a digit and then a dollar sign didn't work. Example: A1$B.
 </li><li>MS SQL Server compatibility: support for linked tables with
     NVARCHAR, NCHAR, NCLOB, and LONGNVARCHAR.

h2/src/main/org/h2/constant/SysProperties.java

@@ -513,6 +513,12 @@ public class SysProperties {
      */
     public static final int REUSE_SPACE_AFTER = getIntSetting("h2.reuseSpaceAfter", 32);
 
+    /**
+     * System property <code>h2.reuseSpaceBtreeIndex</code> (default: true).<br />
+     * Reuse space after deleting or updating many rows in a b-tree index.
+     */
+    public static final boolean REUSE_SPACE_BTREE_INDEX = getBooleanSetting("h2.reuseSpaceBtreeIndex", true);
+
     /**
      * System property <code>h2.reuseSpaceQuickly</code> (default: true).<br />
      * Reuse space in database files quickly.

h2/src/main/org/h2/index/BtreeIndex.java

@@ -142,7 +142,7 @@ public class BtreeIndex extends BaseIndex implements RecordReader {
      * @param p the page to update
      */
     void updatePage(Session session, Record p) throws SQLException {
-        if (database.getLogIndexChanges()) {
+        if (SysProperties.REUSE_SPACE_BTREE_INDEX || database.getLogIndexChanges()) {
             storage.addRecord(session, p, p.getPos());
         } else {
             storage.updateRecord(session, p);
@@ -156,7 +156,7 @@ public class BtreeIndex extends BaseIndex implements RecordReader {
      * @param p the page to remove
      */
     void deletePage(Session session, Record p) throws SQLException {
-        if (database.getLogIndexChanges()) {
+        if (SysProperties.REUSE_SPACE_BTREE_INDEX || database.getLogIndexChanges()) {
             storage.removeRecord(session, p.getPos());
         }
     }

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

@@ -424,10 +424,13 @@ public class Storage {
     }
 
     private void checkOnePage() throws SQLException {
-        pageCheckIndex = (pageCheckIndex + 1) % pages.size();
-        int page = pages.get(pageCheckIndex);
-        if (file.isPageFree(page) && file.getPageOwner(page) == id) {
-            file.freePage(page);
+        int size = pages.size();
+        if (size > 0) {
+            pageCheckIndex = (pageCheckIndex + 1) % size;
+            int page = pages.get(pageCheckIndex);
+            if (file.isPageFree(page) && file.getPageOwner(page) == id) {
+                file.freePage(page);
+            }
         }
     }
 

h2/src/main/org/h2/tools/Recover.java

@@ -679,7 +679,31 @@ public class Recover extends Tool implements DataHandler {
                 } else {
                     pageOwners[page] = storageId;
                 }
-                writer.println("// [" + block + "] page:" + page + " blocks:" + blockCount + " storage:" + storageId);
+                String data = "";
+                int type = s.readByte();
+                int len;
+                switch (type) {
+                case 'L':
+                    boolean pos = s.readByte() == 'P';
+                    len = s.readInt();
+                    data = "leaf(" + len + ")";
+                    if (pos) {
+                        data += " pos";
+                    }
+                    break;
+                case 'N':
+                    len = s.readInt();
+                    data = "node ";
+                    for (int i = 0; i < len; i++) {
+                        data += "[" + s.readInt() + "]";
+                    }
+                    break;
+                case 'H':
+                    int rootPos = s.readInt();
+                    data = "root [" + rootPos + "]";
+                    break;
+                }
+                writer.println("// [" + block + "] page:" + page + " blocks:" + blockCount + " storage:" + storageId + " " + data);
             }
             writer.close();
         } catch (Throwable e) {

h2/src/test/org/h2/test/TestAll.java

@@ -286,16 +286,12 @@ java org.h2.test.TestAll timer
         System.setProperty("h2.maxMemoryRowsDistinct", "128");
         System.setProperty("h2.check2", "true");
 
-// 2009-05-15: 25 test fail with page store (first loop)
+// 2009-05-15: 25 tests fail with page store (first loop)
+// 2009-05-18: 18 tests fail with page store (first loop)
 // System.setProperty("h2.pageStore", "true");
 
 /*
 
-index grows:
-runscript from '~/Desktop/merge.sql';
-create table test(id int, name varchar, primary key(id, name));
-@LOOP 10000 merge into test(id, name) values(?, 'test' || ?);
-
 BaseIndex or TableData should have its own compareMode
 (default is: Database.compareMode when created).
 standard: COLLATE for each column (MySQL, SQL Server)