Index: openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java
===================================================================
--- openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java    (revision 520127)
+++ openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java    (working copy)
@@ -237,6 +237,7 @@
     public boolean useSetStringForClobs = false;
     public int maxEmbeddedBlobSize = -1;
     public int maxEmbeddedClobSize = -1;
+    public int inClauseLimit = -1;
     public int datePrecision = MILLI;
     public int characterColumnSize = 255;
     public String arrayTypeName = "ARRAY";
Index: openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/OracleDictionary.java
===================================================================
--- openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/OracleDictionary.java        (revision 520127)
+++ openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/OracleDictionary.java        (working copy)
@@ -116,6 +116,7 @@
         maxConstraintNameLength = 30;
         maxEmbeddedBlobSize = 4000;
         maxEmbeddedClobSize = 4000;
+        inClauseLimit = 1000;

         supportsDeferredConstraints = true;
         supportsLockingWithDistinctClause = false;
Index: openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/PagingResultObjectProvider.java
===================================================================
--- openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/PagingResultObjectProvider.java   (revision 520127)
+++ openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/PagingResultObjectProvider.java   (working copy)
@@ -22,6 +22,7 @@
 import org.apache.openjpa.jdbc.meta.ClassMapping;
 import org.apache.openjpa.jdbc.meta.FieldMapping;
 import org.apache.openjpa.jdbc.schema.Column;
+import org.apache.openjpa.jdbc.sql.DBDictionary;
 import org.apache.openjpa.jdbc.sql.Result;
 import org.apache.openjpa.jdbc.sql.SQLBuffer;
 import org.apache.openjpa.jdbc.sql.Select;
@@ -146,31 +147,23 @@
         if (size <= 1)
             throw new InternalException("size=" + size);

-        // try to find a good page size.  if the known size < batch size, use
-        // it.  if the batch size is set, then use that; if it's sorta close
-        // to the size, then use the size / 2 to get two full pages rather
-        // than a possible big one and small one.  cap everything at 50.
         int batch = getFetchConfiguration().getFetchBatchSize();
         int pageSize;
-        if (size <= batch && size <= 50)
+        if (batch == -1)
             pageSize = (int) size;
-        else if (batch > 0 && batch <= 50) {
-            if (size <= batch * 2) {
+        else if (batch > 0)
+            pageSize = (size < batch) ? (int) size : batch;
+        else {
+            if (size <= 50)
+                pageSize = (int) size;
+            else if (size <= 100) {
                 if (size % 2 == 0)
                     pageSize = (int) (size / 2);
                 else
                     pageSize = (int) (size / 2 + 1);
             } else
-                pageSize = batch;
-        } else if (size <= 50)
-            pageSize = (int) size;
-        else if (size <= 100) {
-            if (size % 2 == 0)
-                pageSize = (int) (size / 2);
-            else
-                pageSize = (int) (size / 2 + 1);
-        } else
-            pageSize = 50;
+                pageSize = 50;
+        }

         _page = new Object[pageSize];
         if (_paged.length > 1)
@@ -341,10 +334,11 @@
         // create where condition limiting instances to this page
         JDBCStore store = getStore();
         Select sel = store.getSQLFactory().newSelect();
-        SQLBuffer buf = new SQLBuffer(store.getDBDictionary());
+        DBDictionary dict = store.getDBDictionary();
+        SQLBuffer buf = new SQLBuffer(dict);
         Column[] pks = mapping.getPrimaryKeyColumns();
         if (pks.length == 1)
-            inContains(sel, buf, mapping, pks, start, end);
+            createInContains(sel, dict, buf, mapping, pks, start, end);
         else
             orContains(sel, buf, mapping, pks, start, end);
         sel.where(buf);
@@ -389,6 +383,32 @@
     }

     /**
+     *  Based on the DBDictionary, create the needed IN clauses.
+     */
+    private void createInContains(Select sel, DBDictionary dict, SQLBuffer buf,
+        ClassMapping mapping, Column[] pks, int start, int end) {
+        int inClauseLimit = dict.inClauseLimit;
+        if ((inClauseLimit == -1) || ((end - start) <= inClauseLimit))
+            inContains(sel, buf, mapping, pks, start, end);
+        else {
+            buf.append("(");
+
+            int low = start;
+            for (int i = 1, stop = (end - start)/inClauseLimit; i <= stop; i++) {
+                inContains(sel, buf, mapping, pks, low, low + inClauseLimit);
+                low += inClauseLimit;
+                if (low < end)
+                    buf.append(" OR ");
+            }
+            // Remaining
+            if (low < end)
+                inContains(sel, buf, mapping, pks, low, end);
+
+            buf.append(")");
+        }
+    }
+
+    /**
      * Create an IN clause limiting the results to the current page.
      */
     private void inContains(Select sel, SQLBuffer buf, ClassMapping mapping,