Concurrent CREATE TABLE... IF NOT EXISTS in the presence of MULTI_THREAD=TRUE…

Concurrent CREATE TABLE... IF NOT EXISTS in the presence of MULTI_THREAD=TRUE could throw an exception.

h2/src/docsrc/html/changelog.html

@@ -53,6 +53,10 @@ Change Log
     this is a problem for various libraries, including Apache Lucene.
 </li><li>MVStore: use RandomAccessFile file system if the file name starts with "file:".
 </li><li>Allow DATEADD to take a long value for count when manipulating milliseconds.
+</li><li>When using MV_STORE=TRUE and the SET CACHE_SIZE setting, the cache size was incorrectly set,
+    so that it was effectly 1024 times smaller than it should be.
+</li><li>Concurrent CREATE TABLE... IF NOT EXISTS in the presence of MULTI_THREAD=TRUE could
+    throw an exception.
 </li></ul>
 
 <h2>Version 1.4.186 Beta (2015-03-02)</h2>

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

@@ -104,6 +104,10 @@ public class CreateTable extends SchemaCommand {
         if (!db.isPersistent()) {
             data.persistIndexes = false;
         }
+        boolean isSessionTemporary = data.temporary && !data.globalTemporary;
+        if (!isSessionTemporary) {
+            db.lockMeta(session);
+        }
         if (getSchema().findTableOrView(session, data.tableName) != null) {
             if (ifNotExists) {
                 return 0;
@@ -130,10 +134,6 @@ public class CreateTable extends SchemaCommand {
         data.id = getObjectId();
         data.create = create;
         data.session = session;
-        boolean isSessionTemporary = data.temporary && !data.globalTemporary;
-        if (!isSessionTemporary) {
-            db.lockMeta(session);
-        }
         Table table = getSchema().createTable(data);
         ArrayList<Sequence> sequences = New.arrayList();
         for (Column c : data.columns) {