With the MVStore option, when using multiple threads that concurrently create…

With the MVStore option, when using multiple threads that concurrently create indexes or tables, it was relatively easy to get a lock timeout on the "SYS" table.

h2/src/main/org/h2/command/ddl/Analyze.java

@@ -122,11 +122,13 @@ public class Analyze extends DefineCommand {
                 // (which is the case if we are within a trigger)
                 // then we can't update the statistics because
                 // that would unlock all locked objects
+                synchronized (db) {
                     db.updateMeta(sysSession, table);
                     sysSession.commit(true);
                 }
             }
         }
+    }
 
     public void setTop(int top) {
         this.sampleRows = top;

h2/src/main/org/h2/command/dml/AlterSequence.java

@@ -104,9 +104,11 @@ public class AlterSequence extends SchemaCommand {
         // would keep other transactions from using the sequence
         Session sysSession = db.getSystemSession();
         synchronized (sysSession) {
+            synchronized (db) {
                 db.updateMeta(sysSession, sequence);
                 sysSession.commit(true);
             }
+        }
         return 0;
     }
 

h2/src/main/org/h2/command/dml/Set.java

@@ -107,8 +107,10 @@ public class Set extends Prepared {
             database.setCluster(value);
             // use the system session so that the current transaction
             // (if any) is not committed
+            synchronized (database) {
                 addOrUpdateSetting(database.getSystemSession(), name, value, 0);
                 database.getSystemSession().commit(true);
+            }
             break;
         }
         case SetTypes.COLLATION: {