Fix ABBA deadlock between adding a constraint and the H2-Log-Writer thread.

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

@@ -1708,7 +1708,20 @@ public class PageStore implements CacheWriter {
      * @param index the index to add
      * @param session the session
      */
-    public synchronized void addMeta(PageIndex index, Session session) {
+    public void addMeta(PageIndex index, Session session) {
+        Table table = index.getTable();
+        if (SysProperties.CHECK) {
+            if (!table.isTemporary()) {
+                /* To prevent ABBA locking problems, we need to always take the Database lock before we take the
+                 * PageStore lock. */
+                synchronized (database) {
+                    synchronized (this) {
+                        database.verifyMetaLocked(session);
+                    }
+                }
+            }
+        }
+        synchronized (this) {
             int type = index instanceof PageDataIndex ? META_TYPE_DATA_INDEX : META_TYPE_BTREE_INDEX;
             IndexColumn[] columns = index.getIndexColumns();
             StatementBuilder buff = new StatementBuilder();
@@ -1723,17 +1736,11 @@ public class PageStore implements CacheWriter {
                 }
             }
             String columnList = buff.toString();
-        Table table = index.getTable();
             CompareMode mode = table.getCompareMode();
             String options = mode.getName()+ "," + mode.getStrength() + ",";
             if (table.isTemporary()) {
                 options += "temp";
             }
-        if (SysProperties.CHECK) {
-            if (!table.isTemporary()) {
-                database.verifyMetaLocked(session);
-            }
-        }
             options += ",";
             if (index instanceof PageDelegateIndex) {
                 options += "d";
@@ -1748,6 +1755,7 @@ public class PageStore implements CacheWriter {
             row.setKey(index.getId() + 1);
             metaIndex.add(session, row);
         }
+    }
 
     /**
      * Remove the meta data of an index.
@@ -1755,17 +1763,25 @@ public class PageStore implements CacheWriter {
      * @param index the index to remove
      * @param session the session
      */
-    public synchronized void removeMeta(Index index, Session session) {
+    public void removeMeta(Index index, Session session) {
         if (SysProperties.CHECK) {
             if (!index.getTable().isTemporary()) {
+                /* To prevent ABBA locking problems, we need to always take the Database lock before we take the
+                 * PageStore lock. */
+                synchronized (database) {
+                    synchronized (this) {
                         database.verifyMetaLocked(session);
                     }
                 }
+            }
+        }
+        synchronized (this) {
             if (!recoveryRunning) {
                 removeMetaIndex(index, session);
                 metaObjects.remove(index.getId());
             }
         }
+    }
 
     private void removeMetaIndex(Index index, Session session) {
         int key = index.getId() + 1;