user clearDefines optimize Oracle PrepareStatement Cache memoery use

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -1279,8 +1279,8 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
                             if (entryIndex++ != 0) {
                                 buf.append(",");
                             }
-                            buf.append("\n\t\t{reuseCount:");
-                            buf.append(entry.getValue().getReusedCount());
+                            buf.append("\n\t\t{hitCount:");
+                            buf.append(entry.getValue().getHitCount());
                             buf.append(",sql:\"");
                             buf.append(entry.getKey().getSql());
                             buf.append("\"");

src/main/java/com/alibaba/druid/pool/DruidDataSourceMBean.java

@@ -56,18 +56,8 @@ public interface DruidDataSourceMBean extends DruidAbstractDataSourceMBean {
 
     void setPoolPreparedStatements(boolean poolPreparedStatements);
 
-    /**
-     * ActiveCount峰值
-     * 
-     * @return
-     */
     int getActivePeak();
 
-    /**
-     * PoolingCount峰值
-     * 
-     * @return
-     */
     int getPoolingPeak();
 
     Date getActivePeakTime();

src/main/java/com/alibaba/druid/pool/OracleUtils.java

@@ -0,0 +1,17 @@
+package com.alibaba.druid.pool;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+import oracle.jdbc.driver.OracleStatement;
+
+
+public class OracleUtils {
+    public static void clearDefines(PoolablePreparedStatement stmt) throws SQLException {
+        PreparedStatement raw = stmt.getRawPreparedStatement();
+        if (raw instanceof OracleStatement) {
+            OracleStatement oracleStmt = (OracleStatement) raw;
+            oracleStmt.clearDefines();
+        }
+    }
+}

src/main/java/com/alibaba/druid/pool/PoolableConnection.java

@@ -96,6 +96,10 @@ public class PoolableConnection implements PooledConnection, Connection {
 
         throw new SQLException("Error", t);
     }
+    
+    private boolean isOracle() {
+        return "oracle".equals(holder.getDataSource().getDbType());
+    }
 
     void closePoolableStatement(PoolablePreparedStatement stmt) throws SQLException {
         if (this.holder == null) {
@@ -118,6 +122,10 @@ public class PoolableConnection implements PooledConnection, Connection {
             stmt.clearResultSet();
             holder.removeTrace(stmt);
             stmt.setClosed(true); // soft set close
+            
+            if (stmt.getHitCount() == 0 && isOracle()) {
+                OracleUtils.clearDefines(stmt);
+            }
         } else {
             stmt.closeInternal();
             holder.getDataSource().incrementClosedPreparedStatementCount();

src/main/java/com/alibaba/druid/pool/PoolablePreparedStatement.java

@@ -81,6 +81,10 @@ public class PoolablePreparedStatement extends PoolableStatement implements Prep
     public PreparedStatementHolder getPreparedStatementHolder() {
         return holder;
     }
+    
+    public int getHitCount() {
+        return holder.getHitCount();
+    }
 
     public void setFetchSize(int rows) throws SQLException {
         currentFetchSize = rows;

src/main/java/com/alibaba/druid/pool/PreparedStatementHolder.java

@@ -26,7 +26,7 @@ public final class PreparedStatementHolder {
 
     private final PreparedStatementKey key;
     private final PreparedStatement    statement;
-    private int                        useCount = 0;
+    private int                        hitCount = 0;
 
     public PreparedStatementHolder(PreparedStatementKey key, PreparedStatement stmt){
         this.key = key;
@@ -41,12 +41,12 @@ public final class PreparedStatementHolder {
         return key;
     }
 
-    public void incrementReusedCount() {
-        useCount++;
+    public void incrementHitCount() {
+        hitCount++;
     }
 
-    public int getReusedCount() {
-        return useCount;
+    public int getHitCount() {
+        return hitCount;
     }
 
 }

src/main/java/com/alibaba/druid/pool/PreparedStatementPool.java

@@ -49,7 +49,7 @@ public class PreparedStatementPool {
         PreparedStatementHolder holder = map.get(key);
 
         if (holder != null) {
-            holder.incrementReusedCount();
+            holder.incrementHitCount();
             dataSource.incrementCachedPreparedStatementHitCount();
         } else {
             dataSource.incrementCachedPreparedStatementMissCount();
@@ -70,7 +70,7 @@ public class PreparedStatementPool {
         if (oldHolder != null) {
             dataSource.closePreapredStatement(oldHolder);
         } else {
-            if (holder.getReusedCount() == 0) {
+            if (holder.getHitCount() == 0) {
                 dataSource.incrementCachedPreparedStatementCount();
             }
         }